ThomasEdwardLane.pdf

m*m !:6yAy~ru Kiiolheque mciaie 

du Canada 

NOTICE 

meq~a~$of~hbnucnolmshca~J~dP~cndPn~~pm 

IN) u w ~ u B ~ ~ c ~ I 

y a y 01 Ihe ongfm lhes~r wbm nea for mcml lmng 

~~~el~0nhas~eenma0e10en~el~e~9hcst~il 

lyol gua ~o.lIs~po.ra~~rw~ncg~a~~er.penp.m~e~r~~ 

16 oe b lh-rc mmse au m rmll~maqe hnr a.onr 

rep

The auhor has gmted an bremabk nm. 

exclusbe toencedlowino LheNaWoMIUbw 

ofCana(atorepmduce.loan. dlsmMeorseU 

wpies of M e r thesis by any means ma m 

any farmor format, &no mls &%is aY&We 

to lnleresled ~emons ' 

L'au(eur aaemrd6 une hxme.Wmable el 

non e w e oermeltant B la BMnthhue 

MtimaIe du Canada de reemduife. &er 

dlsbinuer ou vendre des wiles ae si m&si 

Oe Welque mmiere el sous quelque fome 

O J ce ~ so: m,r - - mpnre . - .- - drc - -- ~rnmnldrec -. .- . . .-.-. - no -- 

ceae these A la diipasifi des personnes 

int6ress9s. 

he au~lorreuw ownemhipof me wfit 

In hislher thesis. Neither Be lhesis nor 

substantd extracts lrom it may be printed or 

otherwise reproduced without hislher permission. 

C- wnservelapm~tedudmitd'au~~~ 

quipmtbsa~.NibB~senidse~b 

substantiels de c&ci ne doivent etn 

im~imm8s ou autfement reproduils sans son 

autorisation.

SUBJECT CATEGORIES 

REPRINTS 

Y " W 1 

MO S," 

MIIT"EMIIIIC5 

MICIOBIOLOC* 

M,NsRALm" 

PALEONTOLOGY 

PILEOZODLLIT" 

V*AI)MACDLOW 

P",L05OW" 

D""S8CS 

eensr., 

A,Orn,C E,.n~nlc.l*LI.O*I1" 

El.m.nUiYA"~tl" 

*/* E".lW 

M.IDDlolan 

Mo,,E",ar 

NU

DO~I~TIQN, BREa31LTION RMI ZINC IIlIERWWTIOH 

m WEIR PmxmmIC, mTIGRAmIc RND m 

- 

m ReWLTI011~S 

INlllBUDWRST. GmxB ORODP IORmVTCIAu) 

AT DmIa'S !mmm, mm 

(c) 'Chmes Edward mns, H.Sc 

A thesis aubnitted to the Sohwl c: Graduate 

Studlea in partlel fulfllhent of tha 

requrrmnts for the degree of 

Doctor of Philosophy 

. Oepa~tnent of Earth Sciences 

Mmrial university of Newfwndlnnd 

.Tan*ay 1990 

St. John's, Nwfwniiland

The sphalsrlte deposit at Newfoundland Zinc nines near narlieln 

~srbour, western ~evfoundlend is situated in the upper part of the Lmer 

ocdovician St. George Group, a cmpiex ot dolostones, limestones and 

breccias in ths middle of a Lawer Paleozoic shallav-water, carbonate 

~latfona sequence. It is a zino-dominated Mlssiasippi Valley Type [HVTl 

depposit, a svhtype of WYTs that is characteristic of the Appalachians. 

phis study shows that zinc qeralization acsurred during one phase of e 

cmplex history of repaated dolwitiretion and fracturing of the host 

carbonates along northeast-trending lineaments. This history is 

Interpreted through an integrated analy6iS ef the sedhentolqic, 

stratigraphic and structural framwork, petrqrsphy, cathodolminercence 

and gwshemirtry. 

me upper St. George Group carbonates were deposited along the 

edge of the tropical Iapetus Ocean during Early to early Middle Or&- 

vician tine when the paesive emtinema1 wrgin began to experience the 

initial effects of plate convergence. Shallow subtidal muddy carbonates 

(-toehe Porntion) shailuued upwards into restricted-water, rhythmi- 

cally interbedded pcloidal grainstones and mudstones (Peloidal or Costa 

Bay Member) and peritidal laminites and bur--mttled mudstones 

(guathuna Formation). Defamation and fragmentation of the platform 

and marine regression during early Xiddle Ordovician the resulted in 

the regional St. Oeoma Unmnfomity and the formation of rak-matrix 

breccias from subsurface karst. The mine stratigraphy records a minimum

oF 5 stages of faulting, rubsudacr dirsolulion and erosion of the 

platfom at this the. The platform was qradually flooded during niddln 

OrdwlCisn timp as the uppsr mnber of the Aguethuna Pormatlon nnd 

limestones of ths Table Point Porntion were deporiled over the st. 

~wrge unsonfomity. mntinupd convergence of the corltinental margin 

caused collapse of the platform end gsnsration ot a foreland basin in 

which a thick sequence of siliciclastic flyssh war dcpsited and 

eventually overridden by Taconlc thmst shpets. 

Seven dolomite crystal types clr generations (I through VII) 

crystallized in far major settings. Micracryatalline, eyngenatis 

dolostones (I) rlth enrichea '"0 replaced subtidal ta psritldal mud- 

stones at or near the surface. Some of these dolostones vers then 

incorporated as olasts in congl-ratea end solution braccias. Compos- 

ite diwnetic crystals (11) grew during burial forming turbid, repla- 

iii 

CIVB corea near surface and clea. rims at depths where pressure solution 

0300 lo) was active. Pore-filling, clear, zoned dolomite went. (111) 

sealad met rmieing porosity in early dolostones. 

Spigsnetitic marae dolostonejephalerits IDIS) cwlexes werprintd 

the earlier dolnnites. They formed smnd fractvre systems as extsnsivs 

~tratahund Lmdies within, and local discordant Lmdies asmDs the 

Catoche Porntion. Thsir devel-nt occurred in 5 min stages: (1) 

llsgional cwressian -aerated linear, stratabound fracture ramas along 

faults and amund rock-matrlu breccias. (2) Xenotopis pre-ore dolmites 

(IV) replaced dolostone-mottled limestones end formed zebra fabrics 

along fractures. 13) Hydrothermal (I4ooC rode) ore fluids caused 

extensive aiesolvtion of corbonstes. (4) Sulphides precipitated in two

stages along frastum zones es fracturing, faulting and diaaah~tion 

continued. (5) mat-ore hydmthernal dolomites (v, VI), dminnted by 

replacive and pore-filling saddle Bolmites with depleted "'0, crystsl- 

lized around widespread, dilatant fractures forming spar hreccian, 

ps8udobrecci.s and ooarse sparry dolastones. Faults associated with 

regional uplift displaced the D/s cnpleiles end formed fluid conduits 

creating a fourth end final environment for late fault-dated, turbid 

doltmites (V11) which replaced limestones. 

The genesis of epigenetis dolosto- and sulphiaes is Interpreted 

to be the result of regional fracturing during the initial stager of the 

Siluro-Devonian Acadian Orogeny. Rising geotheml gradients generated 

by structural thi&ening of the must probably caused warning of basinal 

fluids, the release of mtsls and sviphvr from minerals in the eedhnents 

end baement and the formation of hydrothermal convection in the 

ssdhntary pile. Steep fcsct,xss pemtrntea the base of ths aedimn- 

tary pile and enabled fluids to rise directly €ran basement depth oC 4 

to 6 h. At the deposit site the warn, Woyant fluids rose to the top 

of fracture aquifer8 where they displaced cwler fornetion waters. 

Couling, loss of co,, hulphate reduction andlox incree~ed pH probably 

accounted for rvlphide precipitation.

I wish to thank e rider of peiple who mads this study posribic. 

Noel James enthvaissticsily supervised the thesis. His extensive 

background in the'gsology of cartanate rocks and western Newfoundland 

influenced the dirsstion and soope of this study. He provided partial 

financial support for laboratory analyses and field wrk thmgh his 

NSKRC grant. ton Bsngatcr initiated the study in the interest of 

do-nting Canadian oarbonate-hosted Pb-Zn deposits. He supplied 

constant enthusiastic support and brought along ewrienced MYT geol- 

ogists during several visits to the mine. Thmugh his authority the 

Oeological Survey of Canada supported the early phases of research. D- 

avid Strong and Bob Stevens, other members of my advisory cornnittae, 

ltrvngly supported the work and lent helpful advise during visits to the 

field area. 

Teak Plplorations Ltd. and Newfoundland Zinc sines Ltd. financial- 

ly and technically suprted the majority of the work. natthcv sleche 

and John May of Teak Explorations Ltd. gave me an extended leave of 

Bbsence to carry out the study. The personnel at the nins were excep- 

tionally cwperative in pmvidiog assess to all areas of tha operation. 

The doowntation would not have been possible without the resources of 

several long-resident geologists on the project: Matthew Blecha, the 

ew10zation manager since 1972; noland Cmssley, mine geologist since 

1975; and Gerry O'Dnnell, an exploration geologist slice 1914. Active

.ining, drilling programs and a compilation pmject pmvid=d new data 

during Lha progress of the study. In particular, a drilling program 

devised by William Bemy of the Teck Corporation helped define the 

geometry of poorly known msk-matrix breccias. 

nario Coniglio and Doug Hawick pmvided guidance in the study and 

description of dolmites and their isotopic chemistry. Mg's work . 

established the regional framwork and petrographic guidelines for this 

study. Eric nmntjoy enthusiastiselly provided critical end conrtruc- 

ti& 0-nts. Ian Knight spent m y hours in the field and in dis- 

cussion and critically read the text. Sheila Stanzel carefully edited 

tm~h of the text end provlded useful cnments on carbonate 

sedhntology. Kathi Stait studied the conodont biostratigrephy of the 

Vi 

nine area. Russell Quick analyzed the carbon mntent of sone dolostones 

and discussed id- on behsviovr of oil-field brines in basins. Scott 

svinden pursed the analysis and interpretation of the lead isotopic 

composition of the galenas. Dercy Taylor helpsd with wch of the 

draftins. Brian sears and Wilf Harsh contributed their photographic 

skills. ~l~lsy Pagan and Betty Ann HbWilllms typed mst of the text. 

Tr-r Payno and J erm Bennett did essential muscle wrk of haullng 

hose and washing underground walls. 

I also had ths gaod fortune of many estmed geologists who 

visited the essential outcrops. To acknowledge a fsv: the late Helmut 

Wednr, the late Wolfgang Uebs, Alan Hoagland, Phil Choquette, Dsve 

bach, ~anier R W ~ Jon , vieta, Joe Briskey, Neil Williams, Ted Hurara, 

wight ~radley, John Oratzinger, Art Slingsby, Dave Symnr, Paul 

Hoffman, peter Ulwd and Tyson Birkett.

The tinre spent during this study was particularly enjoyable 

hecause of the good people of the Daniel's Harbour area and the star€. 

faculty and students at mewrial university. ~n plrticular I want to 

mntlon my hmsmates Paul Hyrow, Sheila Stenzel and Sue Webb end 

~lemin9 Hengal Md I(u.sellQuiek, who kept re mnning and in gmd 

health. 

"li

VOlAJME I 

UBSTWLCT 

ADOsnn~NTS 

TDBLE OP CONTENTS 

LIST OF TILRLES 

LIST OF FIGURES 

LIST OF PIATES 

CXAm 1 IW=IMI 

TABLE 05' CUNl'ENT8 

1.1 General Introduction and Setting 

1.2 History of Uining, Exploration and 

Previma study 

1.3 hlrpsc of the study 

1.4 Organization of the Dosment 

PILRT I THE POSITIM OF NEVPOUM)W ZINC MIHES IN mP 

ReGIONRL SETTING 

CHAPTER 2 REOIMAL SETTING 

2.1 Lmation 

2.2 Relation of the st. George ~rmp to the 

Evolution of the Platfom 

2.3 DeConMtional History of the Platform 

2.3.1 me ~aconic omgsny and Burial of 

the St. George Gmup 

2.3.2 The Acadian Omgeny 

2.3.3 Carhonifamus Structure 

2.4 Carbonsts Diagagsnesis. Dolmitlration and 

svlphide nineralization 

2.5 Lithestratigraphy and Sedimentology of the 

St. George Group

2.5.1 Intrcductim 

2.5.2 Watts Bight Fomation 

2.1.3 Boat Hadour Fomtion 

2.5.4 Catache Fomtion 

2.5.5 Aguathuna Fomtion 

2.6 Biostmtigrapny oE the st. George Omup 

2.1 Lithostratigraphy and Sedirentoiogy of the 

Table Head Group 

2.7.1 Intmduction 

2.1.2 Table Point $'omation 

2.7.3 Table Cove Fomation 

2.1.4 Cape Cornrent Fomtion 

2.8 Biortratigraphy of the Table Head Gmup 

PART I1 SEDIHBNTOLXY MD STWATIGRRPHY 

INTROODCTION nr PPRT 11 

3.1 Intrduction to the Lacd stratigraphy 

3.2 Stratigraphic Control and Review of 

PIWims N-elatare 

3.3 Introduction to ths upper Catoche Porntion 

3.4 Mder C - Upper Nodular mdatone 

3.4.1 Lithologies 

3.4.2 Veetioal Distribution of Litholagies 

3.4.3 Uopohitionsl EnvLmmant 

3.5 nenmsr D - Upper Burrwed Waokestone 

3.5.1 Lithology

3.5.2 Depositional Enviromnt 

3.6 WelFbsl. E - Peloidol Menber 

3.6.1 Lithoiogles 

3.6.2 Distribution of Lithologies 

3.6.3 Oepasiti0W.l Environment 

CHAPTER 4 STRIITIGRAPHY AND SEDIMENMWGY OF THE 

AGUP.RIUNA FORVATION AND TABLE POINT 

FORNATION 

4.1 Intmduotion the Stratigraphy of the 

Aguathune Pornation 

4.2 The laier Member 

4.2.1 Lithologiee 

4.2.2 Dtstribution of Lithologies 

4.2.3 Depositional Envimment 

4.2.4 Interpretation of the Cyclic 

Stratigraphy 

4.3 The Middle nea$er 

4.1.3 Nature and Distrihtion of Lithologiea 

4.3.2 Depositional Envimnmnt 

4.4 The St. Oearge Unoonfomity 

4.5 The Upper n&r 

4.5.1 Introduction 

4.5.2 Litholagies 

4.5.3 Distribution of Lithologis 

4.5.4 Depositional Emrinmment 

4.6 Thm Iauer Teble mint Formation 


4.6.2 Stratigraphic mrkers


4.6.5 Depositional Envimnment 

4.7 Sumary ot the Sedimentary and Stratigraphic 

Evolution of ths Upper st. Georgs Group 

end Lower Table mint Formation 

5.2 Analyticel Methods 

5.3 Dolomite 1-Ron-luminescent mismcrystalline 

dolomite 

5.4 mlomire Type II-Very fine to medium 

rzyrtalllne, turbid dolomite with blue 

to pi& n 

5.5 Dolomite Type III-very fine to medium 

crystalline, clear crystals with bright, 

zoned a 

5.6 Dolomit* Type IV-Fine to medium crystalline, 

I-epla~Bment doldte with red CL 

5.7 mlomite Type v-~ine to megacrystelline 

dohrnites with all red CL 

5.0 oaldte Type VI-Hsgacrystalline dolomites 

with red a 

5.9 Doldte Type VII-Fine to coarse crystalline 

dolomite with red CL distrihted along late 

faults 

5.11 Summazy and Discussion of Fluid Inclusion Data 

5.12 sunmvvy and Discussion of Wen and Carbon 

Isotope Data

5.13 Implications of hsoc Elenent Geochemistry and 

Cathadalminescence 

5.111 sumnary of iblamite Crystal Types and Their 

EvolUtion 

CRAPTER 6 SULPHIDE AND IAYE SULPHATE P-NESIS 

6.1 Introduction 

6.2 Analytical Methods 

6.3 Early Pyrite 

6.4 Early Red Sphslerite 

6.5 Eerly Tan-bmwn Sphelerite 

6.6 Early ye11o.l Sphalsrite 

6.7 Late Yella-broun sphphalerite 

6.8 late Yellow-black Sphalerite 

6.9 Luminescent Sphelerite Oven~mutha 

. 6.10 Galena 

6.11 Late Red Sphalerite 

6.12 late Pyrite and Narcasite 

VOLUME I1 

6.13 late Sulphater 

6.14 Discussion of Fluid Inclusion Data 

6.15 Disc~r~ion of Sulphur Isotope8 

6.16 Significance of Lead Isotops 

6.17 Smary of the Panlagenesis of Sulphides 

and sulphatea 

PART IV EBRLY WWSMNBS AND BRECCIAS 

INTRODUCTION TO PART IV 

CHP.PTBR 7 FdRLY RNE WWSTONES AND FINE R W - 

WTRIX BRECCIAS

7.2 Early Fine Dolostone 

7.3 Fine Rak-Matrix Breccias 

7.3.1 Definition 

7.3.2 Petrography of Fine Rock-natrix 

Breccia 

7.3.3 Omprison with other Breccia Types 

7.3.4 Types d Breccia Bodiss 

7.3.5 The History of Fine-Rosk-Matrix 

Brescias 

CHAPTER 8 ERRLY BlPJCA OOWS'MNES 

8.3 Interpretation 

PART V EPIGENETIC m&XSE OOLOSlONE/SPHULERITES 

mnpms 

CHdPTER 9 IWROOUCTION TO PIGENETIC WRRSE 

WLOSTONE/SPHRLWITE mMPLEXeS 

10.1 Relative Age Relationships of Struoturea In 

the Upper St. George Group 

10.2 Epigenetic Vein Syrtw. and their 

Relationships to Other St~ctures 

10.3 Intsrnsl Structure of Vein System 

10.3.1 Introdvotion 

10.3.2 Early Ccnprassional StNctures 

10.3.3 Dilatant On Stage Fractureli 

10.3.4 post-ore Dilatant Fracturing 

Xiii 

269 

269 

271 

271

CHAPTER 11 PRE-ORE EPIGENETIC DOLOSTONES 

CHAPTER 12 SPHALERIW ORE BODIES 

12.1 Introduction - Relationship batween 

sphalerite Bodies, vein Syrtcms and 

coarse Dolostones 

12.2 Sphalerite Bodiel: Thsir Internal 

~camernrk end Zlnc Grade Distribution 

12.2.1 Description 

12.3 Tha Habit of Minarallzation 

12.3.1 Dsscription 

12.3.2 Interpretation 

12.4 The Geometry and Development ot -site 

Sphslerite Bodies 


12.4.2 Early Spholerita Badies 

12.4.3 Late Sphalerite Bodies 


12.5 Constraints on the Interpretation of Ore 

Genesis 

12.5.1 Intmdwtion 

12.5.2 Setting 

12.5.3 Timing 

12.5.4 Nature and Smrce of the Ore Fluids 

12.5.5 Pathways of the Fluids 

12.6 Interpretation: Porntion of the Ore Bodies 

12.7 SUmaLy 

CHAPTER 13 WST-ORE C O W tQLOSlONE3

13.1 Introd81ction 

13.2 Lithologiea 

13.3 Cmrse Dolostones - Pseudobreccia 

13:3.1 Definition 

13.3.2 Crysill!. 'Pextures of Psavdabreecia 

13.3.3 ~cnersl Fabric and G-atry of 

Pseudobrecoia Beds 

13.3.4 Fabric Elmnts of Pseudobreccia 

Beds 

13.3.5 Interpretation of Pssudobreccia 

13.3.6 Interpretation of Gray Dolortone 

Bandslzebrs Fabric 

13.4 Coarse Wlostones - Spar Breccias 

13.4.1 Distribution 

13.4.2 Intsrpretation 

13.5 coarse spamy Dolostones 

13.5.1 Description and Distribution 


13.6 Dirmrdent Grey Ooloatonea 

13.6.1 Daseriptian end Distribution 


13.1 late Fault-related Oolostones 

13.7.1 Description and Distribution 


13.8 Geochemical zonation in Dololitone Bodies 

13.8.1 &scription 


13.9 Interpretationlsmmazy

mamn 14 SYN~IESIS OF mmsE W~STONEJ 

FPHALRRITE COMPLEXES 

14.1 lntrdvctian 

14.2 Dsvelopnent of the Initial Strvctural 

Fr.mc"0.k 

14.3 Crystallization of Pre-ure Dolortones 

14.4 Major Fracturing and Dissolution 

14.5 Depunition of Sulphides 

16.6 Crystallization of Post-ore Dolortones 

and Calczte 

14.7 Silum-Devonian Faulting and Uplift 

14.8 crystallization of bate ~ault-rslatnd ~olostones 

14.9 Nature of the Basinel Fluids and their 

Transp~rt 

P?4T VI SUMY IWD CONCLUSIONS 

CWLPTER 15 SUWY OF THE SEDIMENTIRY AND BURU 

HISTORY 

15.1 Sedinsntary History 

15.2 Wlmitization and Breceiation during 

Early Burial 

15.3 Epigenetic Dolmitiaation and Sulphide 

Mlneraliaation 

15.1 Dolmaitizoition related to Regional Uplift 

CWPTER 16 CONCLUSIONS 

16.1 Major Controls an Dolomitization and 

Fluid Movement 

16.2 Nature of the St. George Unconfomity 

16.3 Hulti-stage Dolmitization 

16.4 FMng and Nature of sulphide Deposition 

16.4.1 Timing of Sulphide oeposition

16.4.2 Nature 01 Sulphide Depohitim 

16.1.3 Interpretation of Oencsis 

16.5 Nalule and Origin of Epigenetic 

Dolastone Fabrlcs 

16.6 Nature and Significance of the Various 

Bre~cish 

REFERENCBS 

APPRNDIX A - Carbon and Oxygen Isotope Data 

APPENDIX B - Dolomite Geacheniatry 

mmM C - X-ray diffraction analyses of dolomitea 

XPPENDIX D - sulphur leotope Data 

XPPENDIX E - Sphslerite Oemhmistry 

nPPENDIX F - Flnia Inclusion Data 

APPEMIIX G - Lead Isotope Data 

APPENDIX H - Stratigraphic Key to Photographic Logs 

of Collins (1971)

able 3.1 Stretigraph10 Nmenciatvre 2 

Table 5.1 Pharaoteristics of Wlnnite Tyees 129 

Table 6.1 Characteristics of sphalerlto Types 211 

Table 7.1 Coqerison of Dolamite and Dolostone Fypes with 

Classification of Haywick I1980 268 

able 7.2 Breccia T w 281 

Table 7.3 mes uf Brecoie Bodie~ 2.19

US? OF FIGURES 

Figure 1.1 lDcation and geologic ]nap of western Newfaund- 

lend shoring "sin gwlagic terraner, areas of 

stratigraphic study and locolea of vain Pb-zn 

'ahm~nga 3 

Figure 1.2 

Figure 1.4 

Figure 1.5 

Figure 1.6 

Fisors 2.1 

Figure 2.2 

Piguh 3.1 

Stratigraphy of the avtachthonous platforno1 

rocks of the H wer zone and dctsilcd streti- 

graphy ~f Zn-hosting rocks in the Daniel's 

Hsrbaur Mine Area 

Geologic map end cross-section 

of ths Daniel's Harbour region 

Hap d Newfoundland Zinc Hinss 

Cross-s80tion of the mine erea 

Frmemrk of the study 

Stratigraphy of the St. Oeorge Grwp 

in the mine area 

Biostratigraphy of the St. George Gmup 

Detailed stratigraphy of the upper St. George Group 

at Newfoundland Zinc Mhsr 

Figure 3.2 vertical distribution of lithologie8 of the 

peloidal member of the Catoche Formation 66 

Figure 4.1 Correlation of the lower ner&sr 

of the Rwathuna Formatian 72 

Figure 4.2 Location nap for correlation 

of the Aquathuna Formation 

Figure 4.3 Mlltigenerationel brsccla beds nt Table mint 86 

Pigum 4.4 vertical distribution of litholagies of the 

lower &er, Aqathuna Fonmton 90 

Figure 4.5 Correlation of the lowr maeinber of the 

Aguathuna m ation between NW, Table Point 

and northwest Gravels 94 

Rigure 4.6 Stratigraphy of the upper St. George Gmup 

acms a doline . 106

Figure 4.7 isopach map of tne middle end upper numbera 

UE the RWathuna Formation over a doline 

alld structural depression 

Figure 5.1 Distribution of dolomite types 

Figure 5.2 Isotope end fluid inclusion data for 

for Early Dolomites and Calcites 

Variation in imn and manganese 

in L"ed nolomita I11 

Figure 5.4 Isotope and fluid inelusion date for 

Epigenetic Dolmites end Calcites 

Figure 5.5 Isotopic data for Late Fault-Related 

nolamites (VII) 

Figure 5.6 Paragenatic sequence 

Figure 5.7 Fluid inclusion salinities versus 

homo4eniration teveraturen 

Figure 5.10 Relative 0'"D end 6°C cwsitians 

of the dolomites 

Figure 5.11 Calmlatea cumcs for varying waterjrod ratios 

according to: 

(A) Variable B'"0 of the initial fluid; and 

(81 Variable fluid tenyleretvre 

Figvre 6.1 Psragonesis of epigenetic sulphides, blmites 

and calcites 

Fiqura 6.2 Fluid inclusion data frm aphalerites 

Figure 6.3 Distribution of

Figurs 7.1 Cross-section of doloatone bodies 

Figure 7.2 The distribvtloa of five breccia types 

Figure 1.3 A profile of rosk-netrix breccia. 

Figure 7.1 Possible chrmol~gy of events during the 

formation of fine ml-matrix breccia. 

Pigore 8.1 Dolostone evolution fm near-surface 

to burial dolmitizatian 

Figure 8.2 Distribution of deep discordant dolostones 

Figure 9.1 Upper Catmhe dolostone facie. et the Ore horizons 

Fimve 9.2 Relationship bstusen sphalerite bodies. 

structural EO~~OYLS and mck-matrix breceiea 

Figure 9.3 Distribution of faults end vein systems 

Figure 9.4 Distribution of late fault-related dolostones 

in the Table Head Group 

Figure 10.1 Btruoture of the T Zone 

~iguri 10.2 Structure of the east I, Zone 

Figure 10.3 southwest L zone 

Piymre 10.4 Distribution of types of win system 

Figure 10.5 Structural mntml by a cross-fault at the K zone 

Figure 10.6 Structure of the F Zone 

Figure 10.1 Cmss-section of reverse fault- 

SPW breccia b t~~t~res 

figure 10.8 Orientation of veins in the mine area 

Fiwe 10.9 Cross-section of a vein syste. north of the L me 

Figure 11.1 Evolutian of coarse matrix &lostone 

Fiwe 12.1 Cmss-section of an ore bady, the K zone 

Fievre 12.2 longitudinal profile of the lwer K Zone 

Figure 12.3 Detailed zinc grade distribution, F Zone

Fiwre 12.4 moss-section thmugh the east end of the L Zone 

Figure 12.5 Distribution of early and late mlphides 

in the central L Zone 

rigure 12.6 Sulphide eonstion, bong Hole Stope of the t Zone 

Figure 12.7 Model for grmnd preparation and ore deposition 

Figure 12.8 variation in soncentretion of sulphide and 

carbonate with change in pH end 30,. 

Figure 13.1 Regional distribution of *pigenetis coarse 

dolostone in the Larer Or&vlsien of 

northwest Newfoundland 

Figure 13.2 variation of pseudobreccia gemtry 

Figure 13.3 Fabric elements of pseudobrsccis beds 

Figure 13.4 evolution of paeudobreccia 

Fig- 13.5 Late dolmitizstion (VII) along a thrust fault 

Figure 14.1 &hematis moss-section of the Northern 

Appalachians in the late Silurian 

~iguro 14.2 ~ault and stretigraphic-controlled mutes 

of flnid migration 

Figure 15.1 Sedimentary smlution of the Platfom at the end 

of the Early ordovisien and during the early Middle 

Otdovi~ian at the Mine 

ligure 15.2 Relationship of dolanitization events end 

sulphide mineralization to burial of the upper 

St. George Group at Daniel's Harbour

Plate 3.1 

Plste 3.2 

Plate 3.3 

Plate 4.1 

Plate 4.3 

Plate 5.1 

Plate 5.2 

Flake 5.3 

Plate 5.4 

Plate 5.5 

Plate 5.6 

Plate 5.7 

Plate 6.1 

Plate 6.2 

Plate 6.3 

Plate 6.4 

Plete 6.5 

Plate 7.1 

Plkie 1.2 

Plate 7.3 

Plate 10.1 

Plate 12.1 

narker Beds 

LIST OF eWLTB9 

Niddle Catoche normation 

mloidal nember 

Aguathuna Formstion - 

Lminitea, Shales and Burmu-mttled Beds 

nguguathuna Porntion - 

Breccia Beds and Chert* 

Chert Pebble Be& ahve the St. George 

Uncon€ormity 

Cathodolwinesoent Petrography 

Diagenetic Calcites end Early mlmitea 

Oolnnit~~ I and I1 

Dolomite 111 

Epigenetic Dolwiites IV and V 

Fluid Inclusions in Saddle Dolmite and 

Late calcite 

Mloaites V and VII In Coarse Sparry Wlostone 

colaur Phases of Sphalerile 

Early Write, Red and Ten-Bmm Sphalerites 

Early Yellow Sphaleritms 

rat" Sphalsrites 

Pwbore sulphates, Sulphidrs and Pyrobitwien 

Undeqmund -sure. ol a mlmict Rock- 

Matrix Breccia 

Petrwrephy of Rock-matrix Brecciar 

Other Breccia T pzs 

Veins and Vein-bressias 

Distribution of Sphalerite in Darss 

DalostOna Beds

XX iv 

Plate 11.2 Spnaierite Ore Habits 310 

plate 13.1 Peendobreccia ,111 

Plate 13.2 Gray Dolostone Bands and Zebra Fabrics 414 

Plate 13.3 Pseudobrescia Textures dl1 

Plate 13.4 Replacement by Pseudobreccia 120 

Plate 13.5 Soar Breccias I43

Thin study investigates the complex history of dolmitizatian, 

brecciation and aulphide mineraliratlan at Newfoundland Zinc Winsa (Nu) 

near the owstel oonmnity of Dsniel's Harbour in western Newfoundland, 

Canada (Pig.l.1). The IW are body is a typical e-le of a sphsler- 

ite-rich, Hiasissippi Valley-type (MVT) deposit classified within a 

subsraup of zinc-rich types characteristic of the Appalachians (nmun, 

1967; Hoa~lend, 1916; Ohle. 1980; Andernon end macpueen, 1982; Sangeter. 

1963). such accvmvlatians are stratabound within sequences of carbonate 

sedjloentsry rocks and precipitated from low temperature hydrothermal 

fluids durim past-sedimentary epigenesis of areas hundreds of square 

kilmetres in extent. The Daniel's Harbour deposit is an typical sass 

where the are is situated adjacent to breccia bodies and collapsed 

stratigraphy innediately below a regional unsonfomity. In addition the 

sphalerite is hosted entirely within dolostones which are dominated by 

M exceptional abundance of megacrystalline, white bperry dolmite, 

oomnly referred to as baraque or saddle dolmite. 

The NzH ole hcdiea lay within dolostone complexes of the upper 

Catoche PormstIon of the Lover Ordovician upper St. George Gmup, part 

of a Lower Paleozoic platformal sequence of shallow-water carbonate 

sedimentary rocks. me sedimnts accumulated on an extensive carbonate 

platform, more than 50 h inside the shallow water r win of the 

"Laurentian" continent. A regional uncanfomity occurs nsar the top of

Pirure 1.1 Location and Geologic Map of Western Newfoundland shnriw 

nmin geologic terranes, areas of stratigraphic study and looales of min 

W-Zn showings. The distribution of the St. Geame Group is indicated 

in vertical stripes. Important Pb-zn occurrences include Newfoundland 

zinc lines, Trapper (T) prospect, Pikes Feeder Pond (A), Eddies Cove 

East (EC), Cape Noman, Twin Ponds [?PI, Round Pond (UP), sdmn River 

ISR) and mose Am (a) in the south. A Pb shoving occurs in Silurian 

carbonates at mrner Ridge (TR) in the White Bay area.

the St. George G mp bsnenth the Middle Ordwician Table Head Group. 

South of na the st. George Gmup is buried beneath niddle otdmicion 

carbonates of the Table Head Group, siliciclsstic rocks of the Gawe 

Tickle Group and inbricated thrust sheets of the Hlvnber Rm Rllochthon, 

which were qlsesd *ring the Hiddis Ordovician Taconie Drogeny (Pig. 

1.2). 

Geographically, NZN is situated on the coastal plain,of the Great 

Northern Peninrvla of vastern Newfoundland (Fig. 1.1). The Cdro- 

O?dovician carbnate mska and shales underlie a Inrland coastal plain 

which stan& 30 to 150 m above sea level and extends frm the Gulf of 

St. Lawrence at Daniel's Harbour 25 km inland to the Long Range Moun- 

tains. Thc Mountains are en inlier of grenitoid and gneissic basement 

of Precmbrian age which abruptly rises 600 m above sea lave1 f m e 

fault contact with redillentsry r& of the coastal plain; end they 

extend 60 h to the east coast of the Worthern Peninsula. Stesp faults 

define the elongate, northeast-trending mntaln range vhich is 200 !a 

long by 60 km wide. 

The aino deposits, 10 km northeast of Daniel's Herbur, are 

located in an area where the host upper St. Georgs Group is extensively 

wsed (Fig. 1.3). The ooahtal plain to the north and easr is leqsly 

underlain by rocks of the Inrer St. George Grwp and of older Cambrian 

age. In the mine area the upper St. Gaorge G mp and associated zinc 

deposits dip gently to the southweat below the Table Head Gmup to 

depths greater then 100 rn beneath Daniei:s Harbour. This monoclinal 

structure is interrupted by steep. mrth to northeast-trending faults 

whish vertically displace stratigraehy up to 1000 m. 

I

Fig;rr 1.2 St~.atig~aphy of the Autmhthonous Platfoal Rocks of the 

Hldsr Zone and Detailed Stratigraphy of Zins-hosting Rocks in the 

Daniel's Harbour Mine Rrea. Enlarged section (right) nhma that the 

anhalerite at Daniel's Harbour occurs within maire dolostones of the 

uppar Catache Pornation of the St. Oeatge Group. Finely crystalline 

dolostones of the overlyiog llguathuna Formation contain several discon- 

famities which cortelate with the Seuk/Tippecanae saplenoe boundary.

Figure 1.3 Geologic nap and Cross-section of the Danial's Uarhr 

Region smpllsd from gaologlc maps of Newfoundlend Zinc Mines, Knight 

(1985, 1986). Camd and Williams (1986) and Grenisr (1990). PP-1 is 

the laeation of a deep drill hole which penetrates the entire St. George 

G=="P. 

Zinc occurrenssa are designated as follows: 

Nrn - Nedaundl.nd zino nine. 

BD -, Bled 

T - Trapper Prospat 

BA - Bill Adm's Shoving 

PP - Piker Feeder Pond

Nzn is situated in a fault hlmk defined by the coastline to the 

west, Bellhum's Brwk Fault to the north, Brian's Pond Fault to the 

east end Portland Creek Pand to the soutlr (Fig. 1.3). The upper st. 

Csorge Gmp and sone rino deposits ere swsed on the Mike Leke Anti- 

cline. 2 to 3 km west ~f the Brian's Pond Fmlt System. me Wike Lake 

mticline is a north-trending, asmetric open Fold with 20° dips on the 

eastern, faulted flank and gentle 5' dips to the Pouthwest (Fig. 1.0. 

The mine enconposses a 16 km" arse wer which more than 15 ore 

lenses are soattersa (Fig. 1.4). Thasa northeastrard to sedwerd- 

oriented, curvilinear, pencll-shaped Wiea of 3% to 12% zinc have 

dimensions of 10 to 3Gm wide by 3 ta 30m high by 500 to 1000m long. The 

largely mined-out ore lenses total 1.2 million short tons of 8% zinc, 

5.5 million tons of which ocmrred in the L and T Zones, 470,000 in the 

A and X Zones. 450,000 tons in the c mno and 760,000 in other small 

zones. The badies are stcatha within the upr 1D to 4hn of the 

Cstoche Porntion and plunge southuest~ard 5000n down the gently dipping 

west limb of the Hike Lake Anticline. Coarse crystalline, white sparry 

doldtea desorDsd as pseudobrecsias in vein-riddled mcks envelops ths 

sphalerite bodies which are located around the periphery of northeaat- 

trendins stm~tuxal &pression%, faults and fracture zones (Fig. 1.4. 

1.5). The structural depressions are elongate to cirrular, synsedi- 

mntsru to early post-ssdhwntary fsstures associated with solution 

brecsies, described as mek-matrix breccia. (Collins end Wth, 1975; 

lane, 1984). The88 rock-mttix brecciar contain smll vague fragments 

to angular netrescale blocks of dolostone witha a fins to medium 

crystalline gray dolwite matrix. Iw grade mineralized zones, small 

9

Figure 1.4 Map of Nawfaundlend Zinc Mines. A map of the distribution 

01 ore zones (black), subeconomic rho mineralization (stippled), mck- 

olatrix bressies (shaded) and faults of the vppsr Cetoshe Fornation. 

over s dozen ore zones nmed by letters, lie along faults and the 

mrgins of rosk-notrix brecsiea. Structural contours Indicate the 

rosition of the tap of the catoche 8-lion (worn marker bed) relative 

to e datum plans 106 n abws sea level. The axis of the north-trending 

Mike Lake Anticline occurs in the rniddle of the mine area. Two major 

steep feults band the area to the north and east. Ore bodies to the 

east and west of the antloline plunge below the surface at 5 to 10 

degrees. ma1 rtratigrsphls collaese occurs wer mck-matri. breccias. 

Section A-A' across the Pmut Lake m&-matri. bresela and the mln ore 

body, the L Zone, is illustrated in Pig. 1.5. 

Lmatians are indicated for drill holes A-1, 66, 965, UG 1001 and 

1251 from which deteiled stratigraphio sectiona were sonatntcted.

AREA OF NEWFOUNDLAND ZINC MINES 

MIKE LAKE ANTICLINE

VI~UVI! 1.5 C1o~s-s~tion OF the Hine Area 

I canplax of dolortone bodims -rises most of the upper St. 

George Group in the mine area. The smrr-seotion trrtnseota the L Zone 

om m y ana the Trout me mk-mtrix breccia (Fig. 1.4). early 

dolostone bodies include most of tt:e mguakna Iamtion, rmk-mtrix 

breccia. end discordant dolostones. Lais stratabound, coarae dolostone 

Mies OF pseudobreccia and coarse =parry dolortone in the upper Catoshe 

Fornation are associated with zinc nulphides. Discordant, late fault - 

rslated dolostones mound faults whioh displance the other dolaatone 

bodies.

A 

CROSS-SECTION OF DOLOSTONE BODIES 

A'

scattered mcurrenaes of sphalfrites and widespread Eoarae crystalline 

saddle dolmites continue 12 km to the northeast and 5 km to the 

southwest of the mine area along the trend of mineralization. 

1.2 History of lining, Blploration and Pmioyli study 

In 1962 Leitch Gold Minss and Mlw Inc. jointly reconnoitered the 

CBRbro-Ordovioian oarbomte terrain of western Newfoundland for Pb-lo 

mineralization similar to regions of Tennessee, Virginia and Pennryi- 

vania. meir efforts resulted in the di~covery of the N7H deposits in 

1963 when Mike Labshuk found sphalerite mtcrops on a lakeahore which 

becme the R Zone. Ira Watson of Leitch Gold Hinss introduced much of 

the local terminology and was rebponrible for dihcovsry of nabt or the 

ore lenses during soil surveys and drilling between 1963 and 1965. 

Coainco Ltd. optioned the property between 1968 and 1971. Their 

personnel reexamined drill core and defined a stratigraphic frmeucrk 

for' further exploration. During this the psrid Cumin9 (1968) of the 

GSC provided the first published descriptions of the host mck and the 

regional unmfomity. Thres years later a Ccwinco geologist, Jon 

Collins (1911). dsscrihed the rcletionship of sphalerite alneraliratirn 

to stratigraphy and mphasiaad the mortanee of karst breccia bodies. 

As a result of publications by Collins (1971, 1972) and Collins end 

smith (1975) the deposit bsc- e t p exunplf of a karst-related are 

deposit. 

The Teck Corporation acquired Leitsh Gold nines share of the 

deposit in 1972 end together with Prnax Inc, hmught the mine into 

1.1

production is 1975. Wining and exploration drilling coutinved thmugh 

1990 during which tlre 1.2 million tons were milled. hlrirq the early 

stages of mining Comn (19821 studied the host mcks and the irviopic 

geochemistry of the sulphides and cerbonates. At the s m time Diilon 

(1978) analyzed the trace elcmnt geochemistry of the depsit. During 

the late 1970's and early 1980's eowrehensive regimsl studies of 

sedhsntology, stratigraphy, diagenesis and dolaaiti~ation et Me~norial 

University and Newfoundland Departmeat of nines lbavesque, 1918; Prstt, 

1979; Hsy*ick, 1984; Knight and Jmea, 1987) artablirhed a regional 

context with which to relate the NZN deposit. 

1.3 m e e of the ahlay 

IS 

The mat critical aspect for interpretation of IYT deposits is the 

understanding of the thing of mineralimtion. This sense of the 

tewral also has inportant irplicetions for the interpretation of 

dalmitiration. This study nttwts to put the history of dolaaitizs- 

tion, bmoiation and rulphide mineralization in perspective thmugh a 

careful L'e~~nstNEtiOn of the sedimentary and diagennetic events which 

produced the -leu mks of the uppar Cotache Pornatim. Thls 

e,ppmach differs from m st previas descriptions of this and other M11 

deposits. Those studies lamely focus on the geology and gsochmistry 

of th ole-stwe -8. In this study, in contrast, a detailad analysis 

or the orystal cant history incorporates the ore-atrge within a broad 

spectm Of events which produced the host dolastonan. 

Dolostones are described and interpreted in a new manner as the

prduct of several generations of dolomite orystals. This treatwnt 

~eparatas the events that occurred during the burial history. 1n 

addition, detsileo petwraphy and geochemistry in conjunction vith 

underground mpping and anelyris of numemus drill cares have also 

enabled s revealing reoonstruetion of the period of ore deposition as a 

multistage history of structural defommtion, brecclation, dolomilire- 

tion, dissolution and rulphide deposition. 

This study should, thus, be an iawrtant contribution to the 

understanding of dolostones, carbonate breceias and HVT deposits. 

Fifteen or mre years of mining and surface drilling and exceptional 

access to mine wrkings have allowed the collection of a rare and 

invaluable reoord of an PNT deposit. The thorough analysis of the 

rtratigraphy and almitizstion, built on a wealth of previous studies, 

provides an ulmsual understanding of the frmemrk of an HVT deposit. 

The structural setting, probably underemphasized in other HVT deposits, 

is also highlighted. The study also has ilnpartant inplieations for 

other subjects: (1) cyclic sedhntatian m e shallar cartonate plat- 

16 

form, (2) regional unconfomities end karstificetion, (31 the crigin and 

classification of dolostonee, (41 the origin of carbonat- breccias and 

zebra dolostones end (5) replacewent dolmitiration by saddle dolomites. 

1.4 organization of the m o t 

The w l e x nature of the geo!>gy and mltistaged nature of the 

diagenetic history reqvirea the presentation of ths subject in six 

parts, each of which contains several chapters which deal with specific

aqpects of the largar topic. The interrelotianrhlp of these chapters to 

the evolution of ths deposit is s umized in Fig. 1.6. Part a!le places 

NZX within the regional context. The aeeond part establishes the 

sedimentary and stratigraphic frmmrk of the k t rocks, rssulting in 

a new interpretation of shallow carbonate platform sadhentation under 

the influence of tectonics and euntasy. Part three presents the 

petrcgraphic and gaoehanlcai attributes the various crystal types of 

dolomites, sulphldeb and sulphatea. This part of the study elaborates s 

clear, paregenetic sequence of diagenetio events which can generally be 

grouped into an orbvician phase of karst fornation and dolanitleation 

and n later Silum-oevonian phase of deep burial dolmitizatlon @nd ore 

erqlacemnt. This temporal subdivision provides e convenient frmwork 

for the following two sections which cover the nature and interpretation 

of the rock bodlea. Pert four outlines the mltistsge formation and 

karstifieation of early dolostones durlng Ordovician sedimentation and 

burial. Part five describes and interprets the origin of the emnmi- 

call* inportant sphalerite / blwite -1exes. The final aewnt, 

pa:t six, integrates ail Information into e concise synthesis. 

17

lgurc 1.6 Prmwork of the Study 

his g~.aphic relates %lostone development, rphaleritea, dolomite/ 

Ephalerite crystal types and bre00iaS to the, sedimntation, burial, 

pressure solution, solution evsntr and faulting / fracturing. Four 

major settings are indicated on the event calm on the left: (1) 

Sedimentation war associated with the formation of early fine &lo- 

stones, an unconformity and karst breocias. 12) The transition to IDDO 

m burial (termed early burial) war oharsctedred by the developnent of 

atylolites and zoned dolomite crystals to form early burial doloatones 

and doloatone rattles in limstmss. (3) During late burial epigenetic, 

hydrothermal merse dolostoner and sphalsrites formed stratabound bodies 

around faults end vein systms. (4) During regional uplift late fault- 

related dolostones replaced lhertones along faults. chapters which 

describe various aspeat* of this evoMion are inaicatea on the figure.

RIB FUSITXIN OF m I A N E ZINC WINES 

m RIB BEGIomL 5mm.Z

2.1 IAWation 

The Newfoundland Zinc Mines deposlt near Daniel's Herbur lien 

stratabound within the upper part of the Lower Ordovician st. George 

Gmup. These sedimentary carbonates are distributed along the northwest 

coast of Nevfovr~~land (Fig. 1.1). The St. George Group is part of an 

autochthonous or parautoohthonous sequence of Wm-Ordovician shallow 

water platformal sediolents which rest unmnformably on ca. I billion 

year old Grenvillian basement of high grade granite-gneiss. An allach- 

thonous ersdlage of niddle Ordovician Taconic thrust slices of coeval 

deep-water sedhents and ophiolitss locally covers ths autochthon in the 

vicioitles of the Bay of Islands and Hare Bay (Pigs. 1.1. 1.2). This 

unrpr Palsomic tectono-stratigraphic terrene is referrsd to as the 

Hunber Zone (William, 1978). 

Silum-Devonian Acedian structures deform this trctono-stratigraph- 

IC sequence. me Long Range Inlier consists of basmnt rocks that were 

uplifted as a northeart-oriented fault block. Paleozoic nedimnts in 

surrounding lowlands are gently folded, 1acall.l thmstad and diaoecred 

by nunternus deep faults. Allochthons occupy structural depressions 

north and south of this basmnt inlier. Resistart-weathering ophic- 

lites form spectacular table-top highlands in these terrains. carbon- 

iferous sediment- unconformably overlie the muer Paleozoic terra"* in 

the south. They fill pull-apart barins that developed in the vicinity 

of veer Lake end St. George Bey (Knight, 1983; iiyda et a1, 19881 (Fig. 

1.1).

zinc mncrsl~zation aa sphaleritc is widely scattered thmughout 

the autochthonous canbm-Ordovician carbanatss and in distinclivc 

celcite veins in Carbaniferous sediments (Pig. 1.11 (Saunders end 

strong. 1986). sphalerite in the &ro-Ordovician carbonates is 

ganerally associated with coarse dolostonen with Newfoundland zinc Mines 

as the type example. Here sphelerite occurs in eesociation with 

negauystalline whlte dolomite. The sulphides and dolmites occur in 

ttre proximity of faults and in association with a variety of carbanale 

t~recclss. acne of which are interpreted as karst-related collapse 

features (Collins and smith, 1975). The succeeding chapters ley out the 

nature, framework and relative age of the sulphides and relstsd fea- 

tures. 

2.2 Reletion of the St. George G- to the Bv~lution of the Platfom 

Betweln latest Precambrian and the Middle Ordovician the, western 

Newfoundland formed part of the tropical continental mrgin of ancestral 

Laurentia. During the Karly Ordovician this margin faced south along 

the Iapetus Ocean (Scotese et 111.. 1979). Sediments exposed t dsy as 

the st. ~eorge Gmup ac-lated in shallow wins wetar, pmbably 50 to 

100 km in frm the platfom margin which ~OSSOP.IE~ a stasp edge that 

shed breooia debris into a deep water hasin ( Jms end Stevens, 19861. 

The St. George Group records the late history of the rift-drift 

development of this -gin which originated in the late Precambrian wheal 

a mgaoontinent split apart to form the Iepetua mean (Williams and 

stevsns, 1914). Attenvatad continantel crust subsidad as it cooled and 

7

mzine sediments onlapped marly rift-phase terrestrial ailiciclastics 

(Labrador Group) during rapid mrly subsidence (Hlssott and Will~m, 

1978) (Fig. 1.2). Subsequent shallax water, dominantly carbonate, 

sedimentation Gept pace with continued subsidence over the next SO 

million years. The platform evolved through three phases (Jams et ai.. 

1988. 1989): (1) en Early Chrian ramp covered with abundant tcr- 

rgenous sediment (Labrador Gmup); (2) s Middle to Upper Chrian 

narrow. 200 km wlde platfo~m rimed by an outer belt of high-energy 

carbonate sands (Port eu Port Group); and (3) il ioature, low-enorgy Lavsr 

Ordovician platform characterized by a rimed margin and extensive car- 

bonate mud deposition over a broad "epeiric" sea (James et al.. 1988, 

1989). 

The Lwer Ordwician platform evolved through tw, sequences or 

nsgacycles of pmsressive deepening followed by shallowing and emergence 

Wight and Jms, 1987). 'LWo wrlriwide eustatic fluctuations in sea 

level were probably respansibla :or these negacyclrs (Fortey, 1984). 

Variations in subsidence rates, carbonate production end local tee- 

tsnirn, however, also influenced the deve1opme:lt of tLa sequencer. 

Carbonate production. for example, wtpaced subsidence during tiole. of 

shallow water; and both uplEt end faulting airentuated unconfomitiea 

(Knight and Jams, 1987). 

The upper St. Oeorge Group oonstitvted the younger megacycle. 

13 

Najor marine inundation onlapped an emergent platform and the Laurentian 

oraton leaving en upward-deepening sequence of peritidal end subtidsi 

carbonates (upper Boat Harbour and lwsr Catoche Pomtionr). After 

mexirtm transgression the catoche Formation shallowed upwards into early

dol.mltieed, peritidal redinmnta of the Aguethuna Porntion. 

The stratigraphy oE the upper st. George Group and the overlying 

Table Head and Caose Tickle Croups records convergence of the aceanic 

lithosphere with the continent. The platfom responded by frag~oenting, 

foundering md beinq buried beneath dsep-water sediments and transported 

rmks of ths ellochthons. A regional uncontomity near ths top of ths 

St. George Gmup roinsides with faulting of the platfano (Lane, 1984; 

Knight and Jams, 387; Stenzel and Jaoles, 1987). Shallow subtidal 

carbonate redimantation (Table Head Group) continued during subsidencs 

of a block-faulted platfom prior to abruptly fwndered into deep water. 

I\ auaceraion of deep-water ~srbonetes, shales, conglmerates and sands 

(upper Table Head Group and Mose Tickle Group) partially filicd e Eore- 

deep before mlaemnt of the allochthons (stenre1 and Jmer, 1988). 

2.3 Womatio~l Llistmp of the Platfom 

2.3.1 llte TDEM~C Orqmy and mid of the St. Geame Gmvp 

Stratigraphy and sedilnentology tightly constrain the chronology of 

the Taconic Orageny in western Newfwndland. laver to niddle Ordovician 

synomgenic sandstones (e.g. Goose Tickle Group) contain detritus which 

records the progressive westward migration of thmst sheets of oceanic 

cmst (Stevens, 1970). Faulting and foundering of the early Hiddls 

Ordovician platfom reflects the response of the lithosphere to this 

westward migration. rnloicement oE slloshthons is constrained to e 10 

million year period between the de~ition of foredeep sandstones and 

vnconfoLneble overlap of ths Late Ordovician lang Point Group onto the 

I

Hunber Am al!achthon (Stevens, 1970). 

Taconic deformation is largely confined to the elloshthon (stevens, 

1970). Moat deformation occurs along thlurt-bounded shale lneianges and 

only penetrates the autochthon far to Lhe east near the Baie Verte 

Lineament (Ceuwd et al., 19118). 

25 

Vu~i~l of the St. Worge Group reached a maximen between the ~sts 

ordo~i~ian and Gats Silurian prior to uplift during the Rcadian Omqeny. 

Thermal maturation of sonodonts to a OLI of 2 to 2 112 inelies that ths 

St. Gwqe Group at Daniel's Harbour was buried to s depth of 2 to 3 km 

(Noulen and Barnes. 1987). R mnposite overburden of Middle Odovic!an 

sediments (700 a), allochthon (1 - 2 kml and an unknown thickness of 

Upper Ordovician-~Liurian seainrent pmbaly account Ior this maturation. 

an alternative possibility of shallow bvriel but an enomlour geotheml 

gradient has bean suggested (NowIan sno tlarnes. 1987). 

2.3.2 The Acildian Omgeny 

Acadian Eaults and folds affect both the basement and allochthon. 

Basement thrusts are enelgent as th* mng Range Fmnt in the Daniel's 

Harbour area end Lwried to the south behvrth a syncllnorium conteininq 

the HMer Urn ~llochthon (~ewwd end ~illim, 1986). 1n the 

s~prac~stal rocks Steep reverPe and normal faults cut asymmunetric open 

folds. 

Tne age of rrcadian defamation in western Nevfoundlend is poorly 

known. U/Pb ages of zirms in crntral Nevfmndland record siiurlsn 

deformtion older than 423+/-3 PUI (Dunning et al., 1988). The age of 

metamphim near Baie Verte supprts s SilUZir- age of tectonirn

!ndllnleyrr, 1911; oallrneyer and Hibbard, 1984). Continued defo~nut~on 

in the Devonian is lmplisa by the nand lead Thrust on the mrt au Port 

Peninsula. This thrust marks the westeni limit of Acadian deromtion 

since it deforms the Late Silurian (Pridoliaa) Clam Sank Yomation 

(Wiilisns, 1985). .Undeforned early Carbonif6mur (visean) era the 

oldest known sediments to overlap Asedian strvcturca in western Naw- 

foundland (Hyde, 1983). 

2.3.3 Carhiferns Strvcture 

High-angle, dip-slip to strike-slip faults dnilnate Carboniferous 

StNctttreS. Strike slip faults tIend northeast and north-northeast. 

mrrestrial to marine ssdimnts iill moderate-sired basins (the st. 

Laurence) and linear 'pull-apart" bsins (e.g. the Deer Lake and St. 

George Basins) IBraaley, 1982; Knight, 1983; Hyde et al., 1998). 

Diagenesis and dolmitiaation affects all carbonate units of the 

Hder Zone (Pratt, 1919; Jms and !!lappa, 1983; Coniglio, 1985; 

Heywick. 1984; Chow, 1986; Knight, 1986; Stenzel, in prep.). A rela- 

tively unifozm pattern of cementation and reeryrrtsllization is remg- 

mired. Synsedinentery radial fibrous cements we widely observed In 

specific faciss. Early lithification Dssurs by equant to prismatic 

Calcite cmsnts and widespread neospar recrystallization. Fine cryntal- 

lins dolortones pre-date caowstion (Haywick, 1984; Coniglio, 1985). 

The onset of pressure solution usually narks the dividing line batwaan 

'6

!,car wrface and deep burial diegenesis (CI., Mattes and ~ountjoy. 

1980). Same fracture-filling bl-ky calcite spar end mst ccarse 

crystalline dolomites post-date end overprint stylolites. sn~e medium 

elystalline dolomites line contemporaneous stylolites (Haywick. 1984). 

later medium to coarse crystalline dolo=toncs surmund late joints and 

faults and, locally, pervasively replace strata (Hapick, 1484). 

Distinctive megacrystalline white saddle dolaoitea are the latest 

dolomite phases and €om the gangue of mst lcad-rim: occurrences. Wte 

calcite fills vugs and fractures, locally, In association with Carbanif- 

emus lead-zinc (Seunders and Stmng, 1986). 

Rasional mlphids ninereiirstion occurs in three settings in 

western Nwfoundland: (1) massive and disseminated sulphides of 

vOlcanic uhalatives in Lawar Ordovician ocean basin redkots and 

subauiface stakworkr of the Bay of Islands Cwlen (swinden et al, 

1988); (2) epigenetic, dolmite-hosted, zinc-rich sulphidea in the 

CmrIan to Silurian carbonates of the Hvlaber Zone (Knight. 1984; 

ssunders and Strong, 19861; and (3) epigenetic lead-zinc sulphides in 

Carboniferas caloita-healed veins and breccia. (Knight. 1983; Saundsrs 

and strong, 1986). 

The Daniel's Harbour deposit belongs to the second type of eul- 

phides. This mineralization-type is widely diatribirted thrmghavt the 

autoehtho~~s carbonates and EZOSE-outs into the allochthoms Car Head 

0- (Coniglio, 1985). The rulphider are associated with saddle 

dolclnites throughout the stratigraphy (Saunderr end Strong, 1986). 

Mineralisation is widespread along particular stratigraphic Intervals 

cbaeacterized by coarse dulmites, veins and hreccias. Three main 

I

mineralizd intervals Include: (1) galena and rphalerite in the lower 

part of the Port-au-Porl croup, (2) sphalerite and minor galsm st the 

base of the Boat Harbour Porntion and (3) sphalerlte ei the base aud 

top of the Catoohe Porntion. Minor sphalerlte also occurs in other 

ports of the Catocho lomation end the base of the Tabls llead Gmup 

(Fig. 1.2) (Knight, 19U; Saundsrs and strong, 1986). 

2.5 Uthostratigraphy and Sedhntoloqy of the St. George Gmp 

2.5.1 IntmduEtion 

The original St. George Series of Schuchcrt and Dunbar (1934) is 

pedefined and given group status by Knight and Jmes (1987). Burrowed. 

fossilifemus, mddy wrbonater and fine crystalline, pritidaldo10- 

stones of th.> St. George Group arm distinguished f m the Cambrian Port 

BY Port Gmup and the Middle Ordovician Tabls Head Gmup. The Port au 

Port Group is poorly fossilifemus, partially rilioislartic end possea- 

8es high-energy oolitic facies, The Table Head Group also stands apart. 

11:s rubbly weatt13ring, muddy, skeletal carbonates abruptly overlie 

peritidal St. George doloatones. 

The St. George Group is divided into Iocr famstionr, in ascending 

order: the Hatts Bight, mat Harbour, Catoche and Ilguathlma Fomstions 

(Fig. 2.1) Bubtida: to intertidal deposits of the watts Bight and 

Catode Fomtionr unded.ie peritidal sediments of the &oat Harbour and 

28 

lwthune Fmtions. Karst unsonfomitias within upper portions of the 

peiitidal units define the taps of the tw onlap-offlap negacycles 

(Knight and James, 1987). The c-sition and depositional envimmnt

Figure 2.1 stratigraphy of the St. George Group in the nine area 

cwiled fm three drill holes (Fiat Pond DDH-1, DDH A-1. DDH 1001) 

(lee rigs. 1.3, 1.4 for drill hole location). Detailed stratigraphy of 

the upper St. George Group (right) shows key marker beds. Vertical 

scales measure depth in lnetrcs fm the top of the St. George Gmup.

IRGE GROUP

of each fomtion is summarized below. 

2.5.2 watts Bight Iornatian (70 - 90 m) 

The watts Bight Formation i s characterized by burmu-mttlcd 

mdstone8 and waokestones, sme grainstoner and wmn atrmtoiitc end 

thrdolite mund complexes and associated che?ts. Prminmt 

Lichenaria-Renalcis biohems occur at G-n Head (Pratt end Jams. 1982) 

OD the Mrt-su-Port Peninsula. The dolate content of the fomtioo 

varies f m pervasive coarse to fine doloatones an the northvsat 

Northern Peninsula to selective dolmltization on the Port-eu-Mrt 

Peninsula to 100% limestone at Canada Bay. 

Depositional Environment - Quiet subtidal sedimentation of burrawed 

mudrtone end eryptalgal-thrmnbolite munds on an open shelf war 

punctuated by deposition of high snergy grainatones. Peritidal lnounds 

formed the base and top of ths fornation during early marine trans- 

gression and late offlap. 

2.5.3 Bost Blvbnv Fmmtion (98 - 156 a) 

The Bwt Harbour Formation comprises metre-thick repetitive 

peritidal sequences that grade uwards from bioturbated lime mudstones 

and wackestones to thrmnbolites and strmaatolites, thinly laminated and 

lenticular bedded mdstones, thrmhlites and stmmtolites and locally 

dololaminite tops. A regional diswnfonity 11 to 36 (metres below the 

top of the formation is characterized by a Isg of chert concretions and 

pebbles (might and James, 1987). The surface is underlain by strati- 

graphic dolostonsa, cmss-cutting fractures and solution cavities filled

with dolmite-chert brecslas (Knight and James, 19871. Prritidul 

cycles, which averlie the disconeomity (the Barbace Cave nwber) have 

distinctive bass1 grainstones and possess only minor, mail nnrunda. The 

basal 30 to 50 m of the formation on the Northern Peninrule is exten- 

sively brecciated with fine end coarse crystalline dolomite matrix end 

coarse saddle dolomites vhich looally host sphalerite. 

Depositional EnVim~lent - The Boat Harbour Formtion is the 

product of peritidol deposition. maw-enemy, !muddy ssdinentation 

laoally interrupted by cryptalgal or microbial boundstone mounds ranged 

frm subtidal to supratidal envimmnts. Repeated flmding and tidal 

elat accretim generated shallwing upward cycles. Pratt and Jms 

(1986) emphasize the inportance of lateral accretion 4. migrating tidal 

islands. The platforn was exposed, karstified and dolomitied during s 

eurtatic regression. Subsequent marine inundation established mined 

Sand and nrud flats in open shallow-water. 

2.5.4 Cntoche amDatim (160 - 180 m) 

The Catoshe Formation is a sequence of shallow subtidel carbonates 

characterized by foesilifemus bioturbated line mudstones to paskstanss 

interrupted by skeletal, intraclest grainstone lenses, throdmlites and 

algal-mararcan mnds. M abundant benthonic fauna includes trilobites, 

brachioMa, sephalopodo, gastropads end socrinoids (Fortey, 1979; 

Knight end Jams, 1981). Rlldatone-filled channels and m e mudcracked 

lminites occur near the bsre of the formation. Hounds which are 

locally mmon m the middle of the formotion (Knight, 1986) dominate 

over 120 metres of section to tho east in Here Bay (:itevens and Jmes, 

32

1976). Charactenstic Catoche iithofaeles are overinln by 15 to LO 

metres of distinctive psloidel end ienestral limestones (Costa Bey 

nerber) on the mrt-au-mrt Peninsula and the Northern Pei.inrula 

(Knight. 1986; Knight and Jms, 1987). 

Portions of the Cetachc Porntion are pervasively dolomitired. 

Coarse dolostones that are associated vith sphalerites rcpiace the uppar 

30 to 60 rn of the formation on the Northern Peninsula. Elsewhere, 

individual bsdr and nattles are sslestively dolodtiaed. The entire 

formation is dolmitised near I It zones (Knight, 1985. 1986). ~ock- 

matrix brecciar within dolostmc canpiexes ere associated vith collapsed 

upper St. George stratigraphy related to karst (milins and Smith, 1975; 

Lme, 1984; Knight and James, 1987). 

O~positional Environment - The Catochc Formation was characterized 

by quiet, mddy deposition an a shelln* subtidal open shelf which was 

frequently interrupted by storm-deposited thin skeletal, intraclastic 

greinrtoner. nlgcl-metazoan mound cwplexer fonned a. energy-dissipat- 

ing barrier on the outer shelf, while scattered thrdlite munds 

flourished on the mddy leeward plattom. Rs the platfom shoaled 

burrowed psloidal uacksstonc to peckatones end fenestral mudstones 

escwnulated in low energy environments and fonned shellow water subtidal 

to peritidel cycles. 

2.5.5 Aguathuna mwtion (5 - 110 m) 

The Aguathuna mmtion ~onaistr of a sequence of cyclic peritidal 

sediments including bur-d lirae to dolmitis mudstones, dololaminites. 

md-cracked dolodtic green shales, stratllbaund breccias and sherts. 

13

The entire formation is dolmitized in the Daniel's llarbaxtr uuea. but 

only partially altered at Port-au-Port. The various lithologies arc 

repeated in the following upward sequence: chert and breccia, lsuinites 

with shales, partially burrow-mttled and burrow-mottled muddoncs. 

msed on this pattern, Collins and Smith (1975) termed the tomation tho 

"cyclic Dolcmit~?. 

Several disconformities interrupt the Fornation. Emsional 

surfaces, thin shales end chert pebbles ore associated with intrafonoa- 

tional breccia# (Collins and Smith, 1915; Lane, 1984; Knight, 19851. 1\ 

regionel disconfomity, 5 to 15 rn belov the top of the formation also 

narks a significant biostratigraphis brenk (Sait, 1908). This discon- 

fomity is well axposed at Aguathuna puarry, Port-au-Port, as an 

BIDS~~MI surface with 16 rn of relief ( hiw. 1968; Pratt, 1979; 

Hewick, 1984; Jams et ai., 1988). A distinctive 3 to 50 m thick unit 

of fine crystalline, calcareous dolostone, quartz pebble beds, liaes- 

tones and shales overlies this diaconformity in the Daniel's llerbaur 

area and is infomlly referred to as the upper rider of the Aguethune 

Fornation. The extreme variations in thickness of the fanoation ere 

related to one or mre phenmna: (1) differantial rates of sedinenta- 

tion on a faulted piatform, (2) emrion of faulted stratigraphy snd (3) 

filling of a karst topography. 

Depositional Envirorunent - wring deposition of the Aguathuna 

mrmstion periodic fioodinq and vertical and lateral sedhnt accretion 

on e pecitidal platform pmduced cyclic repetition of lithologies and 

exposure surfaces. varyiw rates of sedimentation and emsion on a 

block faulted platform pmduced the variable (0 to 110 m) formational 

3.1

thicknesses. Much or ell of the Pornation was altered to fine crystal- 

line dolmite6 of syngenstic or near surface origin. 

2.6 ~iosrratigrsehy of the St. Owrga Owrp 

The biostratigrsphy of the St. George Group is bared on mrnlatioo 

of it5 mid-continent trilobite and oonodont faunas with the Ihx area of 

Iltah. in the western U.S.R. the Ross-Hintns trilobite zones (Hintee, 

1951) have a parallel eonodont stratigraphy (Ethington and Clerk. 1981; 

Roar ct sl, 1982). This biostratigrsphy is correlatd with and sup- 

ported by nummvs North msriccn localities (Ethingcon Md Clark, 1901; 

Wss et 31.. 1982). 

The St. George Group ranges in aga f m early Canadian (Ga- 

sconadian) thwgh aarlp %iter.xkim (Fig. 2.2). Rare rone fossils in 

the watts Bight Wmtion me Gamonadian (byse, 1963). Trilobites of 

the Boat Harbmz Formation correlate with Ross-Hintze trilhbits zones E 

15 

and F in New York and Utah, indicating a liddle Canadian (Deningian) age 

(Fig. 2.21 (Boyce, 1983). me dismnfomity near the tap of the Boat 

ndur Formation coincides with the absence of Ross-Hlntz~ trildita 

zone 0, (byce, 1983). The upper 20 n of tho bat Ha-r Fornation 

contains UPpr zone G, trilobite BenthmasDia -. Trilobite fauna 

of the Catoche Fonation include aiagnostis Rosr-Hintee rone W and H 

species: BenthmasPis aibberula Billings, Carolinites aenacinaca. 

Striaioenalis caudata Billings (Fortey, 1979; byce. 1985). These 

fo~siis give the Catoshe Formation a late Canadian (Casrinisn) age. 

Diagnostic Eom1 Shelly fossils are rare or lacking in the u@pr

~lgure 2.2 liostratigraphy of the St. George Group 

The biostratiqraphy of graptolites, brachlopods, trilobites and 

conodonts is related to the lithostratigrtlphy of the St. George Group 

ond lower Table Point Formation and Ordovician chronostratigrephic 

units.

.I8 

Cetoche and Aqurrthum eor~tions. The trilobite, Benthms~is w- 

- 

riva sintze, knm frm Ross-Hint~e zones I and J, occurs 20 nelr'sr 

belo* the top of the Cstoche Porntion (Boyce, 1985). A lnonospesific 

88rerhlage of grptolites Did-~a~tu~ (emansoaraptus) nitidu. (Hail. 

1958) fm the lowest beds of the Aguathuna Porntion nL Tabla Point 

cmpapara with graptolites f m Bed I1 of the CQW Head Gmup, which 

oantains trilobites of Ross-Hintae zone 1 (Williams et al, 1981). 

- 

Whitsmckian fauna (trilobites Bathwms Pemlexus, Acidi~horus cf. 

A. pseudobsthwrvr and the ortracod Eoleperiditia &white) occur 

within dolostones of the upper member of the Aguathuna Pornation 

(Knight, 1984; Myyce, 1985; willima et al. 1987; Knight and Smes, 

19871. These fossils have a coincident ange over Ross-Hintae trilobite 

mms L ana W, which are rmiterockian (noes et al, 1982). Aparth0~hvle 

brechiopods of the Table Point Formation carrelate with the uppec 

Whitemckian hmalorthis Zone and suggest that the shelly fauna of the 

upper Aguathuna Fomtion belongs either to Iawer or haas1 Upper 

Whiterockian (Ross and James, 1981). 

Gaps in trilobite stratigraphy are augmsnted by conodants found 

thmughout the Mtoche and Aguethuna Formations. Lover Ordovician 

biostratigraphy is knwn only In a prslininary fashion (ethington and 

Clark, 1971, 1981). Stooge (1982) condncted a remnnaiseance survey of 

the St. George Group. Stait (1988) studied the upper St. Gsorge Group 

at Daniel's Harhr ana Table mint. ~i (1989) exmined sonodont 

biostrstigraphy of the St. George Group at Port-au-Port. 

The presence of midmntinent Fauna D (Aco&s daltetus assemblage 

zone) end Fauna B (Prioniodus (Oe~ikiJdus) cmnis assemblage -"el

atfizns the late Canadian age of the lower to lniddlr catahe mmtion 

(stmge, 19821. An abrupt introduction of species (Stouge'r Fauna 51 

OENZS at s lithologicai change to vsry shaliw water aedimnts 75 

metres below the top of the formation. mng the first-occurring 

species, Jumvdontue Wanda. Oistodus mlticomsetus and Semiaeontiadus 

asvnnetricus are identified in J, gitnanda - Reuttemdus nndinus assen- 

2 of lwer nidmtinsnt Fauna 1 (Sweet et al., 1971; Ethington 

and Clark, 1981) (Data frm Stait, 1988; Nolan pers. cm., 1984). ~t 

iY 

Ibex, Utah, J. qsnanda acurr in strata of Ross-Hintze ttilobite zones 11 

and I (Ethington and Clark, 1981). 

Small conodont p~pulstions within the lower Aguethuna Pornation are 

dominated by peritidal fader-specific hyaLine fom including Orepanoi- 

- 

stodur anmlenais, 0. of. inwualis and D. venustusi (Stait, 1988). 

Pteracontlodus cr~todans and Oe~i?cdus intemediua of Midcontinent 

Fauna 2 suggest that muoh of the lower Aguethune Fornation is early 

Whitsrockian (Stait, 1988). 

Mnodonth change abruptly in the uppr Aguethuna Porntion above 

the regional unconfonaity. A facier-specific assenblage belongs to the 

pecitidai/legmnal Trisanadvs - eonwrionidur biofscies of tha 1-r 25 

m of the Table Head Group (Stouge, 1980; Stait. 19881. Midcontinent 

Pmne 4 in these beds co~~elates with the vpper whiteroctian Anmlor- 

this Zone. Several reprted diagnostic fossils no older than ~auna 4 

include Histiodella tableheadensis = holodenteta, Paraprioniodus 

--- 

costatus, Mliti~istodUs subdentatus and La~toshimnathus guadrat. 

IStJt, 19881. 

Cono&nts end Belly fossils collectively suggest that the uacon-

tormity con-elates with the ArenigJLlanvirn bwndary, o world-scale 

break (Fortey, 1984). The unconfornity probably represents a hiatus of 

2 to 5 million years, which ensqanries the gone of Hldsontinent Fauna 

3, part of the lower Whiterockian Stage (Stait, 1988). mswers about 

this time span and the base of the Whitemckian, however, remain 

indefinite because of the limited number end diversity of specics in the 

peritidal lolrer Agathvna Fomtion. 

2.7 Lithostratigrsphy aad Sedhmtology of the Table Bead G ap 

2.7.1 IntntmdU~tim 

The Table Head Grarrp, which was described by lchuchert and Dunbar 

(1934) and Whittington and Kindle (1963). is defined by Klew et el. 

(1980). stenzel st el. (1990) have re-examined the regionallitho- 

40 

stratigraphy. The group is suMiv1ded into three formations: (1) Table 

mint; (2) Table Cove; and (3) Cape Camrent; which respectively am 

distinguish by bioturbated gray limestone, r.4bon limstona and lim- 

stone lnegabreccia (Fig. 1.2). The boundaries of the group are placed at 

the top of the St. (aorge dolostones and at the base of black shales. 

siltstones and sandstones of the Omae Tickle Group (Fig. 1.2). 

2.7.2 Teble mint Pmmation (40 - 260 m) 

The Table Point Formetion mwrises shallow subtidal muddy ear- 

bonatss vith an abundant and diverse fauna. It includes dominantly 

bioturbeted bioslsstic vackestonea and packatones intercalated with lime

mudstones, peloidel pramstones, small simp beds and minor dolosroncs. 

Peritidal sediolsnta of the ksal 25 to 50 m arc called the Spring Inlet 

N&r (20s~ end Jms, 1981) and induds (1) orgilleceour nodular 

wackastonea to padstones, (2) hioturhsted wackertoncs, (3) fenestrai 

!mdstones, (4) dololaminitrs, 15) limestone congimrates an2 (6) 

cwina limestones (Might, 1985, 1986: Ross end James, 1987). A 

dmmtting erosionsi lurfaca =curs within these sediments west of Inure 

Bay (might, 1986). The formation is dolcmitised along faults (Knight, 

1985). 

~epositional Inviromnt - The peritidalto subtidal carbonates of 

the ~abic Point FormUon ramrd the gradyal drouning ol the he- 

foundland Platform during marine transgrearion and platform rubsidencc. 

sadinentation rates equalled subsidence as carbonate lnud deposition 

continued on a shallow open shelf. Variable rates of subsldencs on n 

bloc* laulted platform however controlled the local rare of eedhnta- 

tion and ultimately fomtional thicknessas. High-enemy sand deposits 

and ttseisnicEt slumps psriodically disturbed the substrate (Stenzel end 

James, 1988). 

2.7.3 Table We &tion (0 - 94 m) 

ma Table mve orm mat ion is e deep water slop depost of ribbon 

lhstone consisting of thin intemnlations of black ahale, bioturbated 

hioclilstio waclmstones end calcareous mud tuhidites. Urge scale slump 

folds are o wn. 

Depositional Envimmnt - The Table Cwe Tomation was laid down 

as a veneer d ih md ailicic black mud in deep water an a foundered

2.7.4 caps m~onmrant Porntion (0 -200 m] 

The Cape ~ormrant Formation is characterized DY lh megabceccias 

associatad with siltstonel, sandstones, black shales and celcitur- 

biditer. clasts and olistostrmes include lithoiagles ranging fmm 

cdrian to dminant Table PointITable Cove clasts. 

Oep~sitioml Environment - The Cape Corrmrsnt Formtion consists of 

resedhnanted brecclas intermixed uith deep rater henipelagic muds and 

#etnd/silt turbidites. The lnegabreceias originated fmm erosion of 

platform carbonates uplifted along faults during the foundering of the 

platform. 

2.0 Bhtratigraphy of the Tale Bead G- 

The Table H& GIOUP is ated as uppar Whitemrkien age on the 

basis of trilobites (Whittington and Kindle, 1963), mnodonts (hhraeus, 

1910; StoUge, 19801, graptolites (Finney and Skevington, 1979) and other 

fossils. Trilobite, Sathwrua pemlexis, of Ross-Hintze Zones L lo M in 

the basal Table Point Fornation indicates a lover to upper Whitemkian 

age (Willims at al., 1987). Strata bearing the trilobite, 

-, 56 metres above the formation's base belong to Hhitarakian 

trilobite Zone II (Whittiaiton and Kindle, 1963). The Table W e 

Fornation conteias slightly younger Zone N trilobites. ma brachlpods, 

Awrthwhvla suwrstes n.sp and Rportbhyla (Billings), of the

alrle Point mrmation belong to the upper whiterickian Amnnalorthis Zone 

(Rosa and James, 1987). The vppr Whitemckian oonodont, Histiodella 

tableheadsnais, of Midcontinent Fauna 4 (Sweet et el., 1971) occurs 

thmghout at the Table Point Porntion (Stouge, 1980). Conodonts of 

the North Atlantic middle Llanvirn EoDlacoqnathua aulci.us Zone ere 

limited to the Table Cove Formation IStouge. 1980). The greptollte 

Di~lwra~t~~ deo.ratun ranges from I6 m above' the besa of the Table 

Paht lomation ta the top of the Table Cove omt ti on. D. decoratus 

oozeelates with the upper Whiterookien Peraqlossoqreptus tentaculetns 

("etheridgeiv) zons. 

I3

In Pert 11 the primary sedimentary aspacts ot the mine 

stratigraphy are described. This desoription shows that the oro 

horirona in the upper pert. of the Catoche Fomtion and finely crystal- 

lina cap mcks of the Ilguathuna Pornation acquired their distinctive 

character as Ule cmporition of sedimnts =hawed during uplard 

shelloving of the carbnete platfom. Newly recognized uplard deepening 

redinentary aepsnces result in a new interpretation of shallw ratater 

carbnate sedimentation. Be St. George Unconfbrnity is put into Its 

stratigraphic mbxt as new Informal members of the Aguathuna Porntation 

an dafinad. This stratigraphy demonstrates that the onconformity 

Pomd during e chain of tectonic events which also influwed 

subaudaee karst and sodinentation of the middle and upper merhrr of 

the Awathuna Porntion.

The follnvlng discussion describes the stratigraphy and sdimen- 

tology of the upper St. George Group and lower 50 mtms of the Table 

Heed Group in the mine wee. Lateral relationships are datemined on 

the basis of excellent marker control and extensive drill hole data. 

T%is atretigraphy establishes e frmwozk for the falloving diecussion 

of doiostoner, sulphides, brecciae and struotunll evolution. 

cont.irmms exprsure oP the upper 20 metres of the catoche mma- 

tion, the whole Rguathuna Formation and bhle Head Gmup at the Table 

Point-Freshwater Cove coastal section is correlatsd with cmc at the 

mine (Fig. 1.3). Three deep drill holes penetrate the St. George Group 

into the watts Bight Porntion and are designated DOH 11-1, Undetgmd 

Wil 1001 and US Borax Flat Pond-DDH 1 (Pigs. 1.3, 1.4). The upper 1% 

metres of the St. Gaorga Group in the mine area is mrsd by many drill 

hole fences miented north-northwest (150"-330") with holes spaced 20 to 

90 metres apart. Over. 2600 holes have been drilled in D 250 rqmra 

kilanletre ana that extends be~nd the mine. 'Three huodred drill holes 

io dwn dlp arm penetrate the Table Head Omup. Hap locations and 

logs Of these drill holes are kept on file at the Newfoundland Oeparr- 

lnent of lines end Energy, st. John's, Newfoundland. Figures 2.1 and 3.1 

marire the Lral stratigraphy of the St. George Gmup.

Vlgure 3.1 Drtailed Stratigraphy of the Upper St. George Gmup 

at Newfwndland Zinc Miner 

A dstsilad bsd-to-bsd log of the upper St. George Group is 

cmpiled rrom three drill holes. The middle Catocha Formation is logged 

Ir~l underground drill hole 1001; the upper Cetcche Fomtion f m DDH 

1254; and the Agunthune Porntion f m DDH 965. The locations ot the 

drill holes ere indicated on Fxg. 1.4.

3.2 suatigcaphic mntml and nevi- of ~mious ~mnclatlue 

Nulllema lithoatratigraphic marker beds, such as chert harirons, 

shales, distinctive burmi intervals and fins ciystellina dolostones 

within coarse crystalline mottled strata, ere used for correlation 

[Figs. 2.1, 3.1, P1. 3.11. These markers arg! correlated over the entire 

250 square k

(up i n all photographs is tarard the top of the pege) 

a. The dark. grapgrsen Upper ilrgillite marker is en argillacaous 

dolostone containing quartz silt. Fine 1-atiws range frm nun to 

om-scale. Typical of all drill holes. The scale is in centbetre.. 

b. The "voms" or X marker bed occurs just abwe the base of the 

wathuna Porntion. Cancentrated burmua at the kse grade *wards 

into scattered "uomshaped" traces with whit*, sadale aolmite in the 

centres. hltcrsp photographed at the Table Point coastal section. The 

lens cap Is 50 m in dimter. 

c. R kidney-shaped chert nodule within an upper Catoshe limestone 

preserves bumw fabric. The cherts c%mnly occur 11 n and 21 m 

below the "wnns" marker. Ddll core ample frw WH 1254, 16.8 m belw 

the worms marker (b.w.m.). The male is in centhtres.

ST. GEORGE 

GROUP 

TABLE 33 

STRATIGRAPHIC NOMENCUTURE 

I 

KNIGHT &JAMES 1987 THIS STUDY 

I Upper Member 

I Middle Member 

I 

( 

MINE TERMINOLOGY 

gti3W~ 

CORON 1982 

Bellbums 

AGUATHUNA - --- --upper argillite--- - -(Cyclic Dolonlites Facies 

FORMATION 

Lower Member 

-Coilins and Smith. 1975) 

xorwormsma~er-------------- 

- 

DarkGray- - - --- 

Doiomite 

Peloidal Member I ~;z;ynla Mike Lake 

Fades 

Burmwed Wackestone 

Member I 

CATOCHE Upper Nodular ~ower Daniel's 

FORMATION Member Limestone Harbaur 

BOATHARBOUR 

FORMATION 

Lower 

D~lomite~ 

Facies I

3.3 Intmhntion to the Upper Catoohs Porntion 

The catoshs mnnation is eharesterized by shallar water iiihe- 

facie. SYO~ as fos~ilif~rou~ burmved vsckertones, skeletdl grainstones 

and thrmbolites (Peatt and James, 1986; Knight and James. 190'1). 'Phc 

cdtochs Fornetion in deep drill holes is subdivided into five medrs (A 

through E, rig. 2.1). Members ?+ Ithe lover nodular mdstone) and 8 (Lhe 

lower bvrmwed waaestone) ere similar tm m r s C lths uwr noavlar 

mdstone) and D (the upper burmd vackertone). The peioidai &er 

(E) i s diatinftive and gradationel with the overlying Aguathuna Fom- 

tian. The fallowing discussion is reatlicted to the upper three 

mdars, the litholoqies which characterize the entire fornetion. The 

detalled stratigraphy for ths npper St. GwQe Gmup is illvrtreted in 

FigYre 3.1. 

3.4.1 Litbologies 

PWZ main lithologies characterize this member. Nodular mdstone. 

and burrowed wacliestonea are the dominant ones. &n open mriw fauna 

includes both North Atlantic end North mricnn mfdcontinsntal species 

of trilobites and conodonts (Fortey, 1979; Stait. 1988). 

(1) Nodular mudstone - Thin centimetre-scale lims mdatones; wirh 

few skeletal frawats end rare bur- are parted by millioetre-thin 

partly dolmiii='rd. black argillacews lminetions (PI. 3.2a.d). The 

fabric is g~nerally nodular to fitted, but i. locally evenly parted.

plate 3.2 Middle Catashe Formation 

(Up in the photographs is toward ths top of the Page) 

a. h nodular nudetone omrising a structureless mudstone parted by an 

irregular, dart layer of very fine crystalline dolomite. %wle Em 

DOH 1001. 73 n belw the worn marker (b.w.m.). 1 sm scale. 

b. h bumowed, deletal wackestone fmm Member D ronteina cross- 

seotiuor of cylindrical burmws (arm). Skeletal particles include 

trilobites and crinoidn. Sample from DDR 1001, 58 n b.v.m. 1 cm scale. 

c. An intrackstic grainstone overling a burrowed, skeletal wakeston-. 

Sample fro. DOH 1001. 73 m b.v.m. 1 m scale. 

d. Burrowed vackeatone and nwdrtane with dark argillaceous. dolmitic 

and stylolitic partings. 'Phis core is f m the middle Catoche mmtion. Sample fm DDH 631, M) m b.w.m. Scale in centhetree.

Nduler mudstones are typical oE subtidal to deep marine envimnnents 

(e.9. Wilson, 1975; Ruppel, 1977). Argillaceous. tenigonoua lard- 

nations and minor bioturbation are associated with skeletal-poor muds. 

Turbid waters frm the influx of terrigems mud probably restricted 

habitation by banthonic organism 1e.g. Ruppel, 1977). Increased 

salinities also could have inhibited burrring'when temporary lagwnal 

conditions developed leeward of mound banks. 

(2) 

Burmwed skeletal vackeatones - Thebe ~aokestones and pack- 

stoner are rich in skeletal fragment8 of trilobites, braehiopods. 

ostracods and pelnstozwns (PI. 3.2s). Ccmmn, minute, rubhorizontal 

burrows, 1 to 2 m in cross-saction, are recrystallized to microspar. 

These nubtidal weokestones are interpreted to have aocunulated in low 

energy conditions. 

(3) Grainstones to RudsCones - These grainstones ere thin. 1 to 3 

om-thick, lenses compsed of marre 1 m to 2 a-size mastme in- 

traelasts, pehatozoans and trilobite Eramneots (PI. 3.2.) 

Intraalarts 

are similar in cmposition to underlying strata. These gravelly sands, 

probably twapertites, were emded fro. algal-sponge md mounds end 

partially lithified substratsr, then entrained and deposited in ,shallow 

depreaaions (Pratt 1979; might and Jms, 1987). 

(4) 

l~mmhlites - Metre-thick thranbolite munds with charas- 

tezi=tic clotted fabrics em scattered throughout this member IPratt, 

1979). Cmplex reef frameworks include Renalcis, Lichenaria and a 

56

diverse associated banthnnic fauna (Prstt end Jmes. 1982; Knight and 

Jmes, 19871. Skeletal-intraslast grainstones are comonly assoaisked 

with mounds. Thrdolites probably accreted in the shallow, rubtidal 

photic zone where a and a benthonic fauna flourishad (Pratt and 

Jms, 1982). The munds and associated fauns contributed to the 

surroundittg grainstones. 

3.4.2 Vertical Distribution of Litholwiea 

The nodular mdstones, hioturbated wackestones and fassiiifemua 

grainstoner are all Interoalated (Fig. 3.1). Grainstones occur through 

portions of the section at 30 to 50 ca intewals. Sane of these grain- 

stones occur amund thrdoliter and are asrooiated there vith interca- 

lated mudstone. Uninterrupted nodular mdstone udts may reach B m in 

thickness. Wakestones are generally centimtres in thickness. 

3.4.3 Depoeitional Bnvimnaent 

This nelnber is interpreted to have assmalated on en open shelf 

where a mddy bottom vith a diverse banthonic fauns was repaatedly 

affected by stom and by the influx of terrigenous muds, as iudicated 

by intraclast grainstones and nodular mdsto,~es. Stoms ripped up 

partially lithified muds ad depoeitelt the thin grainstones/rudstoael. 

local biohem also contributed skeletal debris to grainstones. 

Periodic influx and deposition of terrigenous muds clouded the waters 

and temporarily reduced the gmrth of skeletal organisms. 

57

3.5.1 LiLhology 

This unit is composed leqely of one lithorwy, burmwed umhc- 

stone. and is similar to lithology 2 in Mehr C (PI. 3.2b). me 

~YIZOWS, however, a1.e less abundant and the uackestonsz ate vertically 

continuous for up to 10 m. Rbundant *sletal cissts include trilobites 

and pehtozoans. Partially dolomitized beds of unfossiliferous 

burrowed mudstone, 30 to 60 em thick, rhythnically punctuate the 

HBS~BS~O~~S (Fig. 3.1). Small horizontal tubular hurrous, I to 1 m in 

diameter, penetrate lnost of these mudstones. A very shallow water 

Inidcontinant) conodent fauna differs fro. the open mrine fauna with 

North Atlantic speciss in the nodular mudstone member (stauge, 1982; 

stait, 1988). 

3.5.2 D-itimd mimment 

These sediments socreted in very rhallw subtidal settings. 

Widespread shallawing of the pletEom sems to have restricted the 

conodont fauna to midcontinent species. but marine benthonic organism 

still flouris'led. Significant hydrographic changes caused the abntpt 

dilappearan~e of intraclast grelnstonen and nodular mudstones. either 

offshore shwls or regional shallwing attenuated wave enemy. Bvrmving 

organism persisted as mds accumulated slowly in clear waters devilid ol 

the muddy turbidity of the open platfom. Thin fossil-por muds accu- 

nvlated during periodic shallowing into the intertidal (?I aons.

3.6.1 Litholwies 

Peloidal grains form a dominant ccmonent of burrowed limstonrs 

of the vpper Catoche Porntion. Phis nenber is the local equivalent of 

the Costa Bay Meinbet (Xnight and Jmes, 1987). 

(I) Peloidal PackstonelGrainstone - Blmdal packstones and gnin- 

stones comprise 50 to 500 msize peloids, rounded, I to 10 m-dl-ter 

micrite intraclasta, minor skeletal fragmsnts and molds of algal 

.Ilments (PI. 3.3a). mtraclasts and peloids cormonly preserve 

micrltizsd skeletal grains, tubular and "structure 9rmeleuse" fabrics 

of G-, boring alga. and other unknm calcified algae IPratt, 

1979). , sksletel fragments include gastropods, orthocone Eephalowda, 

trilabitea, brachiopods, lithistid swngrs, ostramds and a few pel- 

mto~oans. Matrix is largely altered to 10 p microspar and 20 to 50 lilo 

neospar. 

he grainstona beds which are 1 to 2 m thick have a hetevogsneous 

fabric. Irreymi~~ layers of sicrite and pel~iaal packstone, 1 to 5 m 

thick, interrupt the grainstona (Fig. 3.1; PI. 3.3a). wlict fabrics of 

calcified and filcunentws algae, and grainstone-filled vertical bvrrws 

indicate early binding and lithification. Intraclasts of similar 

mmsition suggest local fraqmentation. Original layering is partially 

disrupted by bioturbation, desiccation(?) and fracturing during diagene- 

pis. mass-attinq infaunalbUI~~~, 2 to 5 m in dimter, are filled 

with Momspar-supported peloids or 20 to 500 p ncosper.

a. 

Plate 3.3 Peloidal nelnber 

Pelo.ida1 grainatone (above arrow) intercalated with mudstone (H) 

nud ploidal packstone (P) layers. Bwmws (light areas) pn- 

etrate all lithologies and greinntone fills a dwelling burrow 

(arm) in the underlying mdstone layer. Veinlets of -me 

calcite cent cut the mudstone and era truncated by stylolites. 

sample f m ODH 1254, 29 m blow wms marker (b.u.m.) I an 

scale. 

b. Burwed wackestone show abundant borieontai burravs and mottles 

(armr) of probable lithstid sponges. These limestone burrorn and 

mottles are wtlined by stylolites and surrounded by -=tea 

misrite partially replaced by finely crystalline dolomite. Suaple 

from W H 1254, 20 m b.w.pt. 1 sla scale. 

5. Ths Yeathered, upper surface of a dolmitized, burrwed waskestone 

ot Table Point exbibits a dense network of horizontal krws of 

Planolites and Paleo~hhvcus. Bar is 10 an. 

d. A core sangle illustrating the abrupt transition f m a burmued 

wsckestone (battan) upwards into a fine crystalline dalortone 

iblackh with lm-sized burrnus (gray). sample f m DOH 1254, 9 rn 

b.w.m. The scale is in centhtrea.

- 

~hr collective presenss of peloide, tile calcified nicrobbo Wrv.- 

nella, e limited, lou diversity fauna and burrows indicate ahallow 

subtidal to intertidal deposition. me abundant poloids end intraclastn 

pmbebly had severe1 origins. Peloids could have Dsen produced by 

calcified and boring algae microbes that are known to ebovnd in shallw, 

Iw energy wwaters (cf. Mooro, 1977; mniglio and J wr, 19851 end by 

infaunal burmuers and skeletal organism. Intraclasts wsre probably 

prolhlced by emdon of litbified carts in the nearshots Isf. Pecsian 

Gulf, Shinn, 19861. SMhr peloidal wackestones with an abundant algal 

fauna are also interpreted ss very shallow, nearshore sediments in other 

h? 

h r Paleoeois sequences in the Appalachians (walker and Laporte, 1970; 

Wenedict, 1977; wars. 1977). 

(2) Burwed wackestane - uurrov:ed peloidal and skeletal wackestanes 

aro characterized by concentrations of horizontal bvrmus of palao- 

phvms, Planolites and chondrites, I to 8 m-wide (P1.3.3b.cJ. The 

bur- which have dietinct clrsular to oval boundaries wetrate the 

matrix hlch is sslecthely delmitized. 'The interior of bvrrova is 

omposed of 10 to'100 lun calcite nwspar and microspar surrounding 

rmants oP precursor peloidal veckestone. Spar-filled mid. of 

Planispiral gsstwoda (-1 and orthoconic cephalopods are 

scattered on bedding planes. 

The burrowed vaokestonea were probably deposited in subtidal 

settings chsrsctericterized by alw deposition and mdne lithificstion 

of mddy redinents. lPlis created a nutrient-rich substrate vhinh was . 

inhabited and thoroughly m rked by lateral deposit feeders (Nerbonns,

lmal). Blnllone~l pmb.b.bly biu.lllerl nn early nulpy "alul.nlko. 

WIICVO~S litl.cr burrowers uf o Ii~rncr s~dirrnl Loll, clrcelat., Iwiu 

conlpitclr.d sl~.uaLu~.c~ (~kd;>lo nl "1.. 19ll41. ll~izi i~:l~~tottescwbl.q. IN 

1.~~1.al or luucr Paleozoic it~L~rl.ldol lo ,itlbl.ldol oarlaimlcl; 1r.g. 

Narlonnc. 198.1) Wl. doc0 "01. spac11y "elEl d"PLl>. 

(3) 

- lrvnacr hdn or wdalone Iran 30 LU 1118 ma lltlck 

an? Ilr8sly ~ryslnlll~te (180 Lo 300 1170) dolonLonc. Couodonmtti nccer, 

bur. no nvlcmIorallli olr preacnL. Hod. brda ore Lhornlyllly Ibloturbotd 

R1 

;tllcl include mulll, l~oriront.~l Cllollduile. bsrrrrvu (I Lo 3 nm In dlov\olur) 

(Pl. >.?a). Bed contocls are ~mov#%,lly ahorp. Scvarnl beds, far exonplo 

thonc 7 to 9 n and 19 to 20 m below tllc 'WMo marker, or0 dnrk pray, 

nlyillvcrwe a1 Llloir balic and nsorly aLrucLumlso8. Ve8.y lllloly 

crystalline dololaminitea locolly occur ol: Lhe base ol lhc 20 at bed 

nbve a bed conlolning whita nodular oherta. Wds toword the top of tlla 

Ulloche WmmsLlo!t tend Lo be plle gray, manslve nltd locally lamlnatod. 

n LaLerel1.y extensive breccla with tine dolomite nvltrix occurs at Lhe 

basa ol s bed 9 m balm Lhe "worms" mrker. 

'l'hem beds are LnlrrpreLad as very shailw svblidol Lo inlortldal 

deposits. Comdont~ and burmrs indicate Iho narlno origin of mat bedo 

and the abrupt bed contacts and orgiliaceous Lo lmalnated lwor prtlooo 

suyqest sudden Elwdiny and deposition above lwar surloces. Deep level 

bummers probably fomd the Chandrib. traces after partial cmpoction 

and deuetering IBkdele et ai., 191111. Lacel ~hert and lminite basas 

gllwst that the muds and, in particular, their lower surfaces were 

rowthemar exposed.

(I) Chsrts - t%w tmes of chert occur along bedding planes. 

White nodules of 50 to 500 iun Inegaquartn and lo to 20 IM mlcroquarlz. 

which oosur beneath the bese of a dolomitired mudstone. 20 m beln* the 

"*oms" marker, and are scattered thmugh the vackestoner of the 

p~loidal laember. Elsck to bmun mlcrocrystalline chert nwhles replace 

burrws within vnckestoner along horizons, 11,end 21 10 beiov the "wonor" 

marker (Fig. 3.1; PI. 3.1~). 

Both types of chert are diegenetic and concentrated belw the 

mudstone units. The silica m y have f amd in the bsdiate subsurface 

during hi* intertidal deposition. The white nohrlsr, chert 20 m belar 

the "womr" narker is particularly suggestive of cauliflower chertr 

whish rppiacs eveporites (cf. Chowns and Ebins, 1970. 

3.6.2 Distribution of LiCho~iee 

A sequence of lithologies in repeated mre than 10 times in the 

stratigraphy of the peloidal member. Key beds and these sequencer are 

correlated laterally over nare than 200 Ionz. Each aquence is cwposed 

fm bottm t~ top of the following units (Pig. 3.2). 

(1) A non-depositional sv-face. an abrupt surface oocurn at the 

contact between an underlying burrmad wackestone and an wrrlying 

mudstone bed. 

12) bed. a 20 to loo cm thick bed of mstly structure- 

less, dark gray ecab0.net mud wasdeposited in very shalln* Meter during 

flooding of the underlying surface. Local preservation of lminites 

svggests periodic deposrtion in the intertidal zone. 

64

Figura 3.2 vcrtical Distribution of Lithologies 

of the Peloidal Munber of tha Cstoshe Fom~tion 

The peioidal m hr is c msed of o dozen or mrs repeated litho- 

logical sequences. each sfwenoe has five distinctive 0-nents. fine 

dolostone (fomerly mudstone) is the basal bed (unit 21 resting abruptly 

upon a "on-depositional snrface (1). These dolostones ccmenly have 

dark gray aqilleceoul bnecl. Burwed vaskertone, unit 3, sharply 

0v~flie6 the dolo~tone. Peloidal grainatones and packstones (0) 

dominate the middle portion of linratonc beds, where they are inter- 

calated with mudstone laxinations and thin beds of burroved vaokcstone. 

Burrwed wackestone, unit 5, 3150 caps Sequences at the top of limestone 

beds.

I% OWED WACKESTONE 

T" 

I 

PELOIDAL GRAINSTONE 

cMiORlTE LAYER 

c ALGAL MAT 

3- 

?g ED WACKESTONE 

t 4 AL GRAINSTONE

(3) Butrared rrackestone. ~hls redimant abruptly overlies the 

upper surface of the nudstone and pass gradationally upwards into 

peloidal grelnstons. Ths vsckestone was deposited subtidally. 

I 0 -pokstone and srainstone. These lithologies laid 

down in shellow subtidal conditions dominate a composite unit with 

alternating on-thick layera of mudstone, grainstone, p~ckrtone and 

wackestene. Burrowing and sparse skeletal frawnts occur throughout 

the unit. Thin beds of denaely burroved nackestone are intercalated 

within the unit. 

(5) Burrowed vackertone. Shallov subtidal, burmued waekestones 

gradationally overlie the peloidal beds and caps a typical aequenoe. 

These mddy carbonates s-nly contain cmoniy large fossils of 

orthoconic EephalqpDdr end planispiral gastropods. Chert. which locally 

replace mottles in the upper 20 pn my reelect migration of silica- 

saturated waters bsneath an exposed surface at the top of the sequence. 

3.6.3 Dopoaitionnl mimment 

During deposition of the peloidsl &er water depths varied 

cyclically fro. very shallow subtidal to inkertid.1. Peloidsl sands and 

burrwed muds ascunouleted in very shallov subtidsl waters and beds of 

rmd accreted in shallowest condirions. A typioal cycle is interpreted 

to have developad as follows (Pig. 3.2). 

(1) A oon-depositional svrface formed at the top of the burmved 

subtidal mds as water ahallowed. The mds became locally emergent and 

rare evaporites, nw represented by chert nodules, precipitated m the 

upper layer of redinent. 

61

(2) As sea level ria* drowned the substrate. md deposition 

preceded L I onlap ~ or grainy, peloidal rcdimnla. ~nrly srdhnto~ion 

of muds varied from shallow subtidal, stom deposits which were bumowed 

hy 

infauna to intertidal acmulations of structureless muds 

and lminibs in the upper pert of the d e r . 

(3) Burmwed peloidal mds and sands were deposited as the shallow 

subtidal substrate deepened. '&be sediments alao my represent the 

buildup of the "carbonate fastory" (3anr.s. 1984) as infauaa and other 

olgsnima besame eatabliahed and contributed peloid:d grains. Cohesive 

mad lmination~, algal mars and early iithification losally stabilized 

the substrate end left vague, thinly-bedded ucitr. & mcmfeuna of 

gast~opod~, nautiloids and aoft-bodied organisms inhabit& and revorkd 

the sedirwoents. Abvndant algae, deposit feeders and erosion of lithificd 

ad contributed abundant psloids and intreclasts which my have accuu- 

lated as uarhover deposits on stabilized mud laminations. 

(4) Peloidal 8ands graded up*ards into burmwed mdr in response 

either to deepening andlor slowed dewsition preceding the cessation of 

sedimentation and the return to stage 1. Slowd deposition was probably 

a response to isolation behind buildups in the outer platform. Deepen- 

ing implies that rapid sea level dmp caused the subseyment emeqence of 

"on-dewmitionrl surfaces. 

60

4.1 Itmauction to the Stmtigraphp of tha niuathm Pomtiw 

The lguathuna Formation at Daniel's Harbour i s an asrslnblage or 

peritidel dolortonen in which huff-weathering, very linely crystalline 

dololminite is the mrt distinctive lithology. Buff-weathering 

dolostonos comprise m e then 80% of the section. At the Table Point 

type section the base of the fornation is pllred 2.5 m bela* the "worn" 

mrker st the base of a tan, partially laminated, fine dolostone (Knight 

and Jams, 1987). The top of the frmation is dram at the abrupt 

transition vith ?die Point limestonee. Thin dololaninites interbedded 

vith limenestone ahve thir boundary are included within the Teble mint 

rowtion. The Aguathuna Fornation in the Daniel's Harbour - Table 

Polnt area is infamlly subdivided into lows, middle and upper %embers 

(Fig. 4.11. Collins' (19711 thesis at Queen's University, Kingston, 

ontario contains a detailed photcgrephic log of the fornation fm DM 

482 (Fig. 1.4). The stratigraphy of thir log is given in Appendix 11. 

4.2.1 UWogias 

The lwer h e r is a unit, epprmimetely 60 m thick, in which

many beds call be correlated beyond the mine *red ovel narr than loo km' 

(rig. 4.1, 4.2). Seven peritidel lithafacies crnprise the &er (Bigs. 

3.1, 1.1). 

(1) Burrowed-mttled to Horaive Oalmils: ~llcse anits, up LO anc 

metre thick. are partially to cawletsly burrwed and poaross a Lwo-ton,? 

texture of grsy-bmwn. very finely (10 pm) crystalline matrix and buff- 

tan, finely (10-50 wn) orystalline burrow rnottlcs (Pi. 4.ld.e). The 

distinctive, Thalorsinoides (Sheehan end Schiefelbain, 1981) burrods 

cmrise netwrks of filled passageways which completely rcvod beds. 

They are up to 5 cm wide in cross-section, although elongated horizon- 

tally, penetrate vertically 1-5 m (PI. 4.ld.e). These iithoinqies also 

contain minor condonts of restricted Hidcontinental type (Steit.1988). 

collins (1971) reported rare fragments of brechiopds, pelecypadr, 

gartmpplr and bryo-ns. Beds are ccnnonly amalgamated int~ units 3 to 

10 m thick (Pi. 4.lf). 

The basal contacts of beds vary frm abrupt to gradational: Lops 

are always sharp. Beds occur either (1) abruptly above rqillacears 

finely laminated dolostoner or coarse centimetre-scale doloiminites, or 

(2) gradationally atme partially mottled massive to coarse laminated 

dolostone (PI. f.la1. The upper several centllmtres are densely 

burrowed and smrscly cryrtalllne (PI. 4.ld). ~rosional surfaces 

ccnnonly form the tops of burroved beds, which laally are capped by 

thin (3 to 10 cm) dololaminites. 

The thoroughly burrowed mud units are similar to !nodern day low 

intertidal to shallar subtidal seainents mined by Callianasss shrimp 

10

Figure 4.1 correlation of the Lower umber of the Rguathvne Formation 

in the Nine Area 

n.le a profile of the Aquathvna Formation is drawn htwesn seven 

representative drill hales and the Table Point type section across ths 

250 %' study area (Flg. 4.2). DDH's 1295 end 1575 were drilled 18 lun 

oast of the mine. The other holes occur around the mine. The lover 

member varies little in thickness. The middle Reraber thickens over 

structural depressions and elsewhere is only a veneer or eroded. Both 

members ere gently folded hnceth the St. Oeoqe UnsonEomity and the 

overlying uppr lnember generally €oms e veneer and locally thickens 

over dolines and at Table Point. 

d.lb Oedr of the lover m h r are correlated. DDH's 965, 1295, 1515 

and 1863 represen1 "0-1 tidal Plat localities. The profile between 

DOH'S 1863, 1868, 1065 and 498 shws an mcreased proportion of burrowed 

lilholagies at margins of later dolines I18681 end within them (1865 and 

498). This implies that subtle subsidence oscurred along the SM. 

structures during deposition of the lower member. 

Key beds and horizons are correlated between all drill holes. 

These units Lnclude thick bvrrwed beds, exposure horizons of breccia 

andlor shale. Note, in particular, the extensivs correlation of the 

llpper Alqil1.ite and the overlying thick hurroved unit.

____Y.,l. ..G

l3igtlre 4.2 location Map far Correlation of the ~guathuna ramtion 

The drill holes correlated in Fig.l.1 form a section approximately 

35 10. long. The Table Point type section OONrs 10 10. north of the 

mine. DDH 965 with stratigraphy characteristic of the region is 

situated 2 10. north of the nine. A serler of northezst-trending fanltr 

"mtrnl several dolines. grabens and areas of uplift and erosion. DDH'S 

498, 1861. 1865 and 1868 represent a longitudinal section across e 

margin of a doline. The section between DOH'S 1295 and 1515 is 18 km 

rlorlheast of the mine.

~ia'e 4.1 %r,athune Porntion 

- hinitea. Shales and Bur--wttlad Beds 

( ~ IS p toward the top of the pge in all yhatajraphsl 

a. vinely laminated, cryptalgal dolostonee grade upwards into e thick 

barmr-mottled bed. MI Gravels, Port au Port. The rcals is in 

centimetres. 

b. raarae, cn-thick dololminitea have abrupt,locslly scoured bases and 

planar to wavy uppar sudaces. Dark gray, argilleceous lsnlna- 

tioos and fleserb part light grey dolostones. Table mint. The 

pen ateasures 14 om. 

E. Algillaceou~ dolostoner contain md crasks, tepee structursr and 

contorted laminations (arm). wavy, strmtoiitic dolostones 

overlie the shales. Table %i:#t. Ths pen measures 14 m. 

d. The upper portion of a burtnred bed containing large bur- hter- 

preted as Thalasrinoider (ar~w). It i s capped by a 60 m-thiek 

Iminics (abwe the lens cap). 32 irregular erosion svrfacs 

separates the leplinite frm the overlying burrowed bed. %ble 

mint. he lens cap measurer 5 cm. 

a. Typical burrow-mttled fabric of dolostone canposed of s thorough 

vertical and horizontal network of burr- (dark gray). Drill 

core (DDH 1868) from the mine. We scale is in millimetres. 

f. A typical burrwed bed, 80 cm thick, diglays crude bedding. large 

burrnus daoinate the upper portion of this bed. Table mint. The 

scale is 20 an.

(sitinn, 1968). Usknoun orgdnismr bulldozed open galleries thmugh the 

redirnrnt (Shaehan and Schiefelbein, 1981). In nlodern nnuiaquer theupper 

liailt or burrw h-enis>tion of ssdhnt occurs on la intertidal 

tlats in the hurald Bahamas (~erdis, 1917) and in :iubtidal aedintents of 

puetermry hypersaline areas (Logan e t ai., 1914). Tha exposed tw: of 

these units iwly that they accumulated in veri shaiiw water. s he 

paucity of marine megafossils end very lim~ted nhrs of conodonts 

imply that this enviroment, and pmbahly the entire pletfom was vely 

shallar and restricted, unlike the mdsm al,alogues cited. Hyperreline 

sea water may have bsen partially reswnrible for this situation. 

(2) Dalolminites: oolalaminitas consist of planar lminations 

tHat vary in thichess from fine (millimtre) to coarse (centimetie) 

she and are grouped in -lets. Thin Iminbione (0.1 to 1.0 m-thick) 

of medim (40 to 60 @) crystalline dolmite rest on an abrupt base and 

grade upwards into fine (10 to 20 @) cryatallme, m to m-thick 

laminations (PI. 4.la.b). % types of lminites occur; they ere 

defined as physical and oryptalgel. Physical lminites have small 

ripple cmss-lamination, wavy to lenticular form and graded evsn 

layering with local emsional bases and a secondary nodular fabric. 

cryptalgal laminites possess very fine m-sized. wavy to crinkly 

laminations. other sadimentaq structures associated with the lminites 

includa tepes, drsieoath cracks, prism cracks, individual burrow- 

wattled lminations, "patterned" mottling, nodular chert, intrafom- 

tionel bressian, fissile elgillaseovs dolortone and post-reoimentary 

fractures. No mcmfossils or conodonts lSteit.1988) occur in the 

I

dololminltes, exeept for gruptolites resovered from a bed at Lha base 

OE the formtion (Yillianv rt al. 1987). 

Planar strmstoiites and mudleilt laminations indicate arc~mls- 

tion on upper intertidal to supratidal dry wd flats devoid of buriavlng 

organism (e.9. Kendall and Skipwith, 1969; Shinn et al., 1969; Logan et 

el.. 1910, 1974). Phundant graded plane beds end smell ripples mply 

that moch of the aedimsnt accreted during flod tides. Desiccat~on 

features end intrafomtional brescias indicate periodic exposure. &me 

nodular cherta and "patterned" dolomites are pmbahle rmants of fornor 

evaporite. (sf. Dixon, 1916; Chovns and Elkins, 1911; see discussion of 

chertsl. 

(3) Hasrivelver~r fino srvstaliine dolostone: Thrse rocks are 

stmtUreleSS with only faint mdicetiona of coarse lamination and/or 

mttil~g due to the lack of coolour contrast. They ganeraliy lie 

transitionally betwhia underlying lminites and overlying burrow-mttlcd 

units. 

Since mssive beds camonly include ev~dence of lamination andlor 

burmu-mattling and occupy their transitional position they probably 

represent deposition between high and la intertidal flats. 

723 

(1) - Gray to green, fisails, dolomitic shales with up to 

25% angular quartz silt and fine sand appear as (11 thin veneers at the 

bare of breccia layers; and (2) ns 30 to W on thick beds within 

dololaninitss. The first type drapes irregvlar erotional or sr.:ltion 

contacts and is closely associated with chert pebbles and nodules (Pi.

I.2b.c). The second type generally grades upslards into dololaminites. 

Host shales are extensive end individoel units can be corralated between 

most drill holes in ths region (Fig. 4.1). shale units at Table Point 

abruptly overlie nodular chert horizons and oontain tepas and Incom- 

plete desiccetiotr ;rack polygons and tepees (PI. 4.10). The shales 

contain no cmodonts (steit, 1988). 1n contunporaneous supretidal 

sedinents of the Romalne Formation, Wingan Islands, Quebec, the same 

lithology preserve= ha:ite cast8 (Essrshers. 1985): casts are not 

present st Table Point. 

The association of rhsles with expure surfaces, wdcracks, 

dololminites and chart nodules implies that the ailicic silty mud war 

deposited on exposed flats. The muds my have laid dwrn folloving 

extensive short-lived flooding. Lacalpnds are ~~~~~~~~d by the 

extensive nature of the units. More likely the muds aewleted during 

periOds of extensive flceding or exposure when abundant wind blan silt 

colleoted on the flats (cf. Oalrptple et el., 1985). The silts were 

probably only trapped when the flats were flooded (sf. Persian Gurf, 

Park, 1976). Mudcracks and tepees hply that desiccation intecrvpied 

episodes of floodi?g. underlying nodular cherts likely replaced nodular 

displaced alphate eveporites which precipitated within the muds. I 

good adwue for the shales is the grey-green silty dolostone of the 

Upper Devonian Dupemv Pomtioo of the Willistoo Basin (Wilson, 1967). 

Ths hlprow silty doloatones ere intemtratified with 'sabkhe' evamr- 

ites and lie above peritidal laniinites. 

79

(5) Cherts - chert iv comnly bssociated *iLh b.eccia horizons. 

the base of sheies, dololdniter dnd the uppar portions ot burrw- 

mttled beds (Fig. 3.1). iibuodant chert is disLribuCed in the tlppcr 10 

to 20 metres of the lower neinbcr. Pratt. (1979) described sir main Lypcx 

DI chert in the St. George Omup: 

(I) 

cryptquartz - Nearly isatrvpic quart% hii. l,,i"llt~.

?late 4.2 Ayuathunn t'ormxtion - Breccia Beds and Ulerts 

a. R pebble r:onglomerate-breccia bed at NW Gravels rests dlscanfcm- 

ebly upon !.he emdcd top of a bumm-mttled linertone bed. Ngille- 

cwous dclobtone forms the base and mtrix around white quartz cobbles. 

Tl!itl-bedded liurjnites oollapse over the bed and are locally incoreoratad 

as breccia Praywnts. The scale 1s in centmetres. 

b. I\ care sample fmm the nine ares exhibits an exposure horizon 

developed upon a burro84 bed and wedein by e thin shale, a chert 

layer and a breceiated dololminite. The scale is in millinetres. 

5. R breccia bd in core f m the mine area mnsists of framnts of 

the overlying daiostone encased in a drik gray dolomite rock-matrix. 

hrerlying fractures are cemented late saddle dolomite. %a scale is 

in sentimetas end inches. 

d. Brecclated do1mt.m beds and multiple exposure horPmns at Tabla 

Mint. The head of the hmer rests on e her errnosure surface eroded 

into the top af a burrwed bed. The amsond surface (arrow1 Cuts a 

dololmlnite bed. A regolith of dolostone cobbles abwe thla surface is 

cmqted by chert. The overlying beds are fractured and partially 

collapsed. The h mr handle is 10 cm long. 

e. n photmicroqraph of a banded, mlcramrartz cobble exhibits nlis 

IaLhe stmctUre (arrow) of warnrites in the micrwartr. Eotryoidal 

chalcedony cements pore spacs. Gravels section. Port au Port. m.r 

scale bar is 1 m. 

f. megaquartz crlstulr exhibit a ghost fibrous texture suggesting 

replacement of evaporites. Tahle mint section. The scale bar is 1 m.

paztially cemnteil by chalcedony. Megaquarlz pebbles lacuily presorvc 

rihrous fabrics (PI. 4.2f). Late megaquartz partially ccwnls and 

~eplaces the rirtrix of these conglmrratas. 

(2) Biscuit to cauliflower-shaped nodules oi white linvid wo- 

quartz ranging f m 1 to 5 cm in di.uneLer arc seattcvcd ulthin doloidmi- 

nite and burmu-nottled beds dawn to depths of.:, m below cxwsurc 

surfaces. 

(3) Layers of small, 0.5 to 1.0 sn-wide, cauliflower nduies aE 

Ei&ysnt white megaquartz and microquartz occur in dololaminiles. 

lathes occur within the nicmymartz nodules. 

81 

(4) Gray to enrber nodul~s of cryptoquartr with flat pancake ahapes 

ln~rporate rhnnba of dolomite in concentric, outer grovth bands. These 

also locally preserve lathe textures. They acur within dololminlter, 

particularly beneath the St. George unconformity, and also occur as 

pebbles which lie on the uneonformity. 

Mast cherts occur at or helm ewpoau1.e surfaces. Most of the 

quartz is disgenetic, but sedimentary clarts indicate very early 

formation of some of the chert. Lathe textures, spherulitea, cauli- 

Flower ~~rp!mlogies, diaplacive nodules end fibrous fabrics are inter- 

preted to be relic rulphste fabrics (sE.Lhovns and Elkins, 1911). The 

stratigraphic pasition at or beneath exporvre surfaces rupwrts origin 

by replecewaent of oabkha-like avaporitef (of. Kenaa11.1984). Lack of 

evaplrite miics in nost ohert, however, suggests that suiphate replace- 

lmnt was minor and silica precipitated by another proses:: such 4s refiux 

of silica-saturated g m d water and crystallizetion from local changer 

in m., sio. or Na concentrations (cf. lavering and Patten, 1962). This

pcwers my be rimilar to activc silica precipitation in dolanilic 

carbonutes at the Coomng Lakes of suxLh Australis (luir r t 31.. 1Y80). 

The conccntrstion or chcrts bneath Lhs unoonfomity alsa suggcrts LhaL 

I11 

elevated Co, camcantrations in meteoric water eaurcd nillciCicali~n (cc. 

Dimks, 1970). 

(6) 

Breccia and coarsely crvstalline dolurtonc - wdr 101 

breccia. 5 LO 50 cm thick. occur at eight or narc levels in tlic Iwor 

mcmbar (rigs. 3.1. 4.1; pi. 4.2). uost ot Lhese mcvr a1 the top or 

coarsely recrystallized burmw-mttled dolostones, but a teu arc 

associated vith sheics in dolalalninite unit;. Brccciu horizons can bc 

correlated over 300 h' in Lha vicinity of the nine. 

sreccias directly overlie planar to irreguiat erosional surfacc;i 

that are lmaily scaliqrd by erosional qullies (Pig. 4.1). The 

breccias themseiver, hoveuer, am complax units, the products or 

multiple events. several emsie, qurraces occur in some breccia hdr 

(rig. 4.3: P1.4.2b). These surfaces are mnrnanly covered vith conti- 

mtre-thick green to bleck shales (P:. 4.ZbJ and scatteted cobbles of 

white and gray bnded cherts; Lhe latter exhibits precursor sulphata 

rabriea (PI. 4.2e). Unguler breccia=. 5 to 50 an thick, -nly 

overlie the ohales an2 cobbles (PI. 4.2a.d; Pig. 4.31. The breccias are 

c-SBd of a mort~mi~t bl 01igO.i~t aS80rtmnt of angular, i to 5 03- 

sized Iragncnts of dolost.one and chert. Host doloatone claats repmaant 

collapsed portions of overlying dololariinites (Fig. 1.3; PI. 4.2s). A 

clsnt-supprting matrix is variably composed of :I) mck "flour' 

re~eystallized to fine to rnedim crystalline dalmitz; (2) blacl: Lo 

green argillaceous material; (3) 1 to S inn-sired dolostone and chert

Yig~lrr 4.3 H~rltigeneiatlonal breccia beds at Table Point 

Three outcrops ot erosional contacts are associated with varying 

muntr of chert and breccia. Spkoln are identiried opposite Pig. 3.1. 

(A) Erorlonal surfacer on burmued beds are overlain by ohert 

cobbles end thin, coarse crystalline dolostone beds. 

(6) secondary gullies cut down into an earlier breccia bed. A 

sl~le vonuer covsrs the gully surfaces. chert cobbles end angular 

fragments of overlying beds fill them, nuggpsting a subsurface origin. 

(C) A m inh of two erosional aurfaces occur in this breccia 

complex. A thin shale and chert cobbles cover the lover surface. The 

aubsurfacs origin of the angular breccia8 is Implied by sagging end 

partial collapse of Intmrcalated and overlying beds.

BRECCIA BEDS AT THE TABLE POIKT SECTION 

.A0 0, WE"L""0 ,'D, 

MLrnM CM.1 .I.* .*.,I m MID" .",CC..I.. I*.LI ...I 

..-"I. ,"l"YI(L ."1TCI. U D U11 "YC. GI".". 

CO."I D(XOI.ml 

LIDUO* IYIIIII. .*I,* .a.s.-", OC.LI. 

C

~;lssls; (4) up to 30% late silica cenlcnt; and (5) late wgacryatailine. 

white saddle dolomite. 

The post-sedimentmy origin of the breccias is dmnstrnted by 

several features: 8reccia-filled veins cut beds. Overlying bcds 

collapse and contributn fraqmenta. nedr 5 to LO n abova breccias sag 

over them (Fig. 4.3). 

NOEL breccia beds are products of lnvltiple events that rcliecl 

sedimentation to burial diegenesis. Ths bases of beds arc irregular 

disconformitier upon which pmbabie wind blown silts settled and 

evaporites crystallired from salt pans or discharging ground water 

endal all, 1984). evapocites appear to have been rapidly replaced by 

chert, which then westhered out as pabble beds. SLmmetolites and thin 

nudstones covered the congienerate beds. Repeated erosion iooelly cut 

down through these beds. Later eubsurfacs solution produced strata- 

bound cavities fallared by breosistion, collapse and sag of overlying 

strata (Fig. 4.3). Throughout burial subsurface fluids repeatedly 

dolmitized and silicified the matrix of these permeable beds. 

(7) 0-1 ctrmtalites - Laterally-linked-heniiphhhidal 

strmatolitea mar at one horizon st Table Point although identifica- 

tion in nearby cores is difficult. Similar stmmatolites are, however. 

distrihted throughout the Aguathuna Formation on the Port-au-Port 

Peninsula and constitute an inportant key to envimmntal interpreta- 

tion. characteristically, 4.d sttmttolitss 10 to 100 cm in thickness 

lie mediately above shales at the bass of burrow-mottled units and 

same laminated beds. 

*I

-th laminated, donvi stmmatolites lorn over a broad environ- 

mental range in mderute to high energy subcidal to supretidal zones 

(cE. shark nay, Rustralia, mgan et ai., 197.1). They cmoniy occur on 

"vet" fiats in the upper intertidal zone and along supratidol ponds Icf. 

Gmteingsr, 1986; Hardic, 1986). The assaletion of Aqusthulla stlonstu- 

litas with breccia beds and shales ilaplier that they grew high on tidal 

Eiats'pmbably at ths lnargin of supratidal ponds. Thelr poritiaa at tho 

base of burrowed beds also suggests that gtromtalites lnad oniap or 

interntittsnt flmding oE the flats. 


ns 

Litholrx~ies of the lower h e r ere distributed vertically in 0 or 

wrm distinctive repetitive seqensea. Each seqvenca generally consists 

of a I to 3 .-thick burrar-mttied unit with an smslonal, conglomeratic 

cap overlain by 2 to 8 m of doiolminites with shales (Fig. 4.1). A 

typical sequence consists sf four ssdhsntary cwonents arranged in e 

consistent order (Fig. 4.4). 

(1) The baaa of the seqvenoe la drcwn at the abrvpt upper surEace 

of a burned unit. The mrf.Ee is either a flat, irregular karsted or 

erosional contaot with rhale-filled cracks. 

(21 R pebbls-mnql-rate w, 5 to 20 n chick, covers this 

surface. Each bed has a basslmilli.eetrs to centhetre-thlck green 

shale (PI. 4.2b). Cabbies, pebbles and layers of chert end megsqvartz, 

awe with relic evaporitis textures, cover the thin shales (Pl. 4.2a.b). 

stmmatoiites and planar cryptalgal lminites cap the pebble bed. Nany 

of these beds ere brecciated due to collapse.

Figure 1.4 vertical Distribution of Lithalogirs of the Lower N-r 

of the Awathuns Wmation 

he lower m&r is cmpsed of seven or inore repeated litho- 

lcqicitl sequences (refer to Fig. 3.1 for the legend). Each sqsnce has 

four main cnponentl: 

(11 An abrvpt erosional contact at the top of burmved heds. 

(2) A thin shale forms the base of pebble-conglomerate units and 

comnly is the only feahva between (1) and (3). Pebble-songlo- merate 

beds ovsrlie the thin shales. marts pbbles end cobbles are over 

printed by pt-dqositional, intrafomtional breccia*. 

(3) minitee dominate 2 to 8 m of section which also contains shale 

beds, chert* and thin burrowed beds. The laminitee losally grade 

upwards into overlying burned beds. Otherwise the contact is abrupt. 

14) Thick burrwed units vary from 1 to 4 rn in thickness and ere an-- 

loualy thick (10 n) st the top of the urembmr. The bds tend to thin 

upwards and upper heds, in particular, shallw uprards into erosional 

w.

(3) Dulolminites dominate a 2 to 7 m thick unit which varier in 

composition from sillimetre-thin cryptalgal lminationr to ccntimetre- 

thick, partially turned beds. Sow units grade upvard into nodular, 

massive 01 burmwsd upper portions, whereas others have abrupt 

91 

contacts with overlying burrowed units. Bases d s- unlts are lo~slly 

argillacews. Intercalated desiccation-cracked &&,I0 to 30 m 

tld*, tsnd to have abrupt bases above dololaminitos with Ehert nodules 

and grade umtd into lminites. Metre-soale burrowed beds occur 

locally ai pert of mall-scale shallwing-uplard cycles. 

(4) Burrow-nottled dolostones in units 3 to 12 n thick eonsilt of 

mlg-ted 10 to 200 m thick beds. The basal contact Is either abmpt 

or transitional. The lower portion conwanly has a fabric of horizontal 

burrnus or vwe mttles. Metre-thick bsral beds thin upwards to 

z~peated 10 to 20 01-thick beds with erosional upper sudacer capped by 

chert-pebble conglolnerates (Pig. 4.3A). Thin lminite caps ossvr 

lo&lly (PI. 4.ld). The upper 5 to 20 om of burrwed units contain 

large burrows. cauliflwer megaquartz and coarse crystalline dolostone. 

R prniinent emsional surface form the top of nort burmved unlts. 

noat packages can be correlated throughout the 300 lon' study area 

but they change in thibese laterally with som units pinching out 

(Pig. 4.1). Thick burmwed units. their erosional caps and shale beds 

arc extensive. Lrvninite units are locally hinated by burwed be& 

around the margins of aynsedhntary faults (Pig. 4.1). 

The thickness of seqvencea varies from 6 to 10 m in the lower 40 n 

of tha lane= amber. An 18 s, thick sequence which fomr the top of the 

member i s cmpsed oE an 8 m lanisitelshale unit werlain by a 10 m

urrwed bed. The mar Wgiiiite morkcr bed odsuer ~n the vppcr part 

of the 8 m lminite unit (Pigs. 3.1, 4.1). 

This vartical ntratigraphy is Eompsrsd to the Table PoinL type 

section and the MI Gravels rection 200 km to the south at Port au Port 

(Fig. 1.1, 1.5). The lover m-r dt Table Point is only 44 m Lhick 

compared to 60 m at the mine and it exhibits general thinning thloughout 

the seetioo. nil seguences, however, are preaent in bolh areas. 

Tibe 60 n thick section et NW Gravela differs in cmnpasition from 

the oaniel's Harbour area. Key beds, however, are present. They 

include majm hurmwed units, shale beds. Eme erosional caps and the 

thick lminite-burwed saquense at the top of the mehr. The detailed 

sequential stratigraphy is ccaplicated by metre-scale intercalations of 

varied lithalogies: laminites, thick shales, Thalaarinoides beds and 

sttmatolitic beds with burrowed to laminated tops. There lithoiogioa 

ere arranged in sequences, 4 to 10 m thick, with 1 to 3 m thick shale 

17 

bases, 1 to 4 m thick stromtolitic to lanlinated mid-sections and 2 to 3 

m burrowed upper portions (Pig. 4.5). They compere closely to those a t 

Daniel's Harm. 

Correlation With other sections of the lower nder at Bonne Bay 

and are ~ay has not been made. Ssguencea within these sections possess 

shallawinq-up~ei-d cycies with cmn intertidal iithoiogiee (Knight. 

1986; Stenrel, pers. cm. 1988). The thick idnite-burmwed sequence 

acurs, hmver, in an anmalmsly thick I\guathuna Formation at Bonne 

my (stenlei, per*. m. 1988). krth of Daniel's Ha?bca,r the lwer 

m+hr is either thin or not present [Might 1985, 1986).

F~,UV~ 1.5 correletion of the Lmr Hernber of the Apathuna 

Pornation Between NewPoundland Zinc Nines, 

Table point and Northrest Gravels 

"rill Hole 965 represents typical stretigrephy of the lwer older 

at the mine area. This same stratigraphy is present at Table Point. 

he thidnesn of the mnber at the tppe section thins. houever, fmm 60 

to 44 m. Key burrowed bads from these sections can be correlated with 

the Northwest Gravels section on the Port au Port Peninsula 200 la, to 

the south. Sequences, 4 to 10 m thick, coware to those at Danlel'~ 

Harbcur. They are onposed of shale be& at the bottom overlain by 

stmatolitio and laminated units capped by bicrmued beds. Bnccia beds 

are minor. Sphls are idsntified in the legend of Fig. 3.1.

TABLE POINT MINE NW GRAVELS 

IDDH 9651 '

TlleaD i'egiol>al correlations of the lovcr'neher have lnporlant in- 

plicatians for the origin of the metre-scale cycler. ?he extensive 

nature of the intertidal units and of the oequcnces in the study area 

and their correlation with the NW Gravels section implies tlut marine 

onlap end offhp apppsrted over broad areas. 

r.a.3 D6psitional miaw-t 

Supratidal Imhites dominated high peritidal flats which wen, 

grazed by burrowers and covered by silicis muds during psriodis flooding 

and marine onlap. Abrupt offlaps exposed the burmved substrates and 

subjected the local platform to erosion and precipitation of evaporitea 

and sherts. Bvapodtes, md cracks and lminites suggest an arid or 

restricted setting for the mud-dmlnated, lw energy pietfom which 

contrasted with t$e grainy substrates of the upper Catoche Fornation 

deposited under mre hdd (7) conditions. 

95 

werall, the Sequences are interprated as upwmd dsepening overall 

although internal analler-scale packages camonly ahallow upads, eg. 

shales to lwinites and burrowed beds with erosional or lminite caps. 

f he derpenlng upwards sequences are interpreted to have developed in 

four Stages: 

(1) e~tetensive subtidal to intertidal flats merged as a subaerial 

bur fa^^ without M offlap cap of linrinites. 

(2) A veneer of wind-blm silt wered the subaerial surface and 

settled wt in hypersaline pools or as a resirme of evaporite 

dissolution. Thin evaporite beds and nohlles precipitated on and 

beneath the -face f m reflure-d brines and hpsraaline pools. Silica

also precipitated f m the brines; partially riplaced sulphatcs; and 

cesnented coeval dolomitee. rmsion and deflalion Lhen incarporated 

quaetz pebbles and cobbler into lag deposits. 

The evnpurites pmbhbly precipitated frm sea water that Elmdad 

the emsionei surfaces and largely evaporated in the mine area. Lunger- 

li\.ed flooding at Northvest orevels Pesulted in the accumulation of muds 

(shale beds) which shalloved upwards into stroo1atolites and supratidal 

lm>initea. similar sequences occurred locally in the area of the mine. 

116 

(3) supratidal carbonate sediments onlapped the sububaerial platform 

ar subsidence and marine inundation of the outboard platform initiated 

cahnste production. Tidal flat sedimentation persisted end kept pace 

with subsidence as tides and winds acsumuletsd thick beds of laminito 

and shale. Sillcic mads at the bare end MdQm of units pmbably 

a~c-latsd during extensive, periodic flooding of the high flats Icf. 

Wilson. 1967; Park, 1916). They gradsd upwards into supratidal lmin- 

ites. 

(4) Btenslve flooding or migration of the intertidal zone over 

the region occurred gradually or abruptly as the rate of sea level rise 

(eustatic rlre + subsidence) exceeded that of scdhentstion. These 

platform-wide events resulted in regionally extensive subtidal to 

intertidal units. Subtidal to intertidal conditions dominated during 

the deposition of the 2 to 4 a thick units as burmuing Thalassinoidel 

infauna exilvatd a fino mdflat. Accretion and/or sea level fluctua- 

tions repeatedly enpahed successive beds toward the tops of sequences. 

~inor elevation differences betwen present day aposed surfacee and 

burrowed flats (1 to 2 m, shin", 1986). however, suggest th~t sea level

changes rare not drmetio. he general lsck,of lminite saps implies, 

howvec, that external eurtatic or tectonls forces caused the emergence 

of the tidal flats. 

4.2.4 Intezpretation of ths CysliF Stratigraphy 

Intmhlction - The cyclic pcritidal stratigraphy within the upper 

St. George Group (peloidal m d r of the catoche Qomtion and the lover 

memhr of the Aguathuna Porntion) reoords fluctuations of sea level. 

Incomplete shellowing upward sequences inply thet eustasy or episodic 

testonism constrained normal shoreline progradation. Vertical con- 

tinuity of tidal flat lithologies also indicates that carbonate sedimen- 

tation rained in near equilibrium with subsidence and eustasy. 

Any sad-ntary mdel must amount for five distinctive features 

of the lower mdsr: (1) Host beds can be correlated thmughmt the 

study srea and .we su6tidal/interti&l units !my extend over mre then 

,200 IM. (2) Repeated burrowed beds within intertidal units am capped 

by expasure surfaces. (3) ThicL lminite and burraned units record 

prolonged periods of supratidel and subtidel/interti&l sedinentation, 

respectively. (4) The lminite units are not slsrsicsl tidal flat saps. 

They are thick; rest on expasure surfaces and nvbseriel conglmerates; 

I7 

and locally grade upwords into intertidal units. (5) The alternation of 

lminite and burned units express long period rhythms that can be 

related to seismicity or climate-controlled HilanltDvitsh cycles. The 

signifisana, and interpretation of these four aspects are first con- 

sidered; than, eustatic end tectonic nwdels are evaluated.

Internretation 

s~btidniblntertidal &i& 

- The widespread 

subtidallintertidal units are interpreted to have resulted f m region- 

al, and passibly larger scale flooding, of the platform. The strati- 

graphy of these units implies that sedimentation mcurred during perhds 

when sea lhvel flvctuation constrained accretion processes. The 

subtidal to low-intertidal burmupd'beds tend to thin upwards within 

enalgmated units and upper beds display repeated expasure caps. This 

Stratigraphy *lies that during sedimentary accretion of the intertidal 

flats rapid and repeated eea level change cawed emergence and flooding 

without upper tidal flat sedimentation (the standard laninite cap). S- 

tranding and exposure of subtidal substrates in the alpine Triassic 

reflects possibly siinila., buf mch higher amplitude see level fluetua- 

tians (lofer cyclothem, Firoher, 1964; Latemar Lhstone and Oolmla 

Pdnoipals, Hardie et al., 1986; Goldharmer et al., 1987). These 

sequences display a sMler upward thinning of subtidal beds which has 

been nodelled as eushtic Milanlo-vitch ~yclel (Mldhenrmer et el., 

98 

1987). altsrnatively this "ward thinnina reflects the decreere in bare 

leva1 during tidal flat accretion. 

- - - - - - 

Bstimated Tim Period oi Tiad Plat Minetttation --The altsrnatiw 

sepcnces of thick I2 to 10 la) units of lminitaa and burrowed beds 

acdated aver long psrioda of the to for. the deepeniw upwmd 

cycles. If deposition of the 60 m thick lwer d e r spanned nesrly 3 

m.(bksed on the biostratigraphy, Chapter 2), then rates of sedimenta- 

tion were relatively slow at apprmhately 2 to 3 an/ lo00 years. 

Individual units, thus, ac-latea over periads betwen 60,OoO and 

500,000 Years and 5 to 7 in-thick, deepening upward sequences developed

in i50.000 to 350,000 years. The lminite unils, Lhus, arc not typical 

laninite caps awe intertidal beds, but, rather. reprosent long periods 

of upper tidal fiat sedinsntatian. 

sianificaoce of Orders of mde8 - Three orders or scales of 

Eyoli~ity occur In the upper St. George Group. 

(1) The first order scheme is overall shallowing on the 

fomtional scale. This oycle is Interpreted as a general aloving of 

subsidence on ths platform relative to sedimentation. 

(2) The second order packaging is deepening upward seymences 2 to 

10 n thick. Their composition reflects varying rates of sea level 

chltnge and sedimentation. Long period sea leva1 oscillations or 

episod!~ seismicity ocourred over 150,000 to 350,000 year Intervals. 

Subtidal/ intertidsl burmwed units esmlated during sea level maxim 

when significant marine oscillations caused dramatic wergence and 

flwding of the aubtidel flats and prevented upper tidal flat sedimenta- 

tion. The erosional caps of burrowed units probably marked significant 

hiatuses during sea level minima. Following sea level minima offshore 

flmding reestablished carbonate production and inshore upper tidal flat 

sedimentation whish mntinued in equilibrium with regional subsidence 

and gradual sea level riaa. 

(3) Third order netre-scale cycles within semnd order packages 

nmtly shallow upwards and are cmonly arrested. These essentially 

represent episodes of sedimentary accretion following flmding. within 

upper tidal flat units thin shales, hurrnred beds or f omr evaprites 

grade uprardn into rtmeitolitse and supratidal dololaminitas. In 

99

100 

subtidal/ intertidal units burroved beds are cappd by Lhin laminites or 

emsiunsl a:rfacea. The characteristic arrested tops suggest either 

that mderate sea level ossillalion or gradual "bsckg~ound" uplift of 

the platfern enposed the flats. 

Eustasy, episodic tectonism or a cwinstion of the Lwa generated 

the sea level changer whish controlled this cyclicity. 

The M~tani~ Ilodel- Regional testonism related to plate wnver- 

gence fragmented the platfom and caused portions to subside 

differentially during Late Early to Early Middle Ordovician the 

(stenael and James. 1987, 1988). Condensed stratigraphy of the lover 

&er north of the mine and subtidal facie. along rynsedimentary faults 

at the dne indicate tectonic effects on subsidence (Fig. 4.1). 

Variable rates of subsidence wer entire fault blocks or larger arees of 

the platfom possibly acaounted for the extensive nature of m beds 

and cycles. Under this tectonic scenario subtidsl aonditions existed 

during aeisds episodes of rapid subsidence pvnctveted by intdttent 

uplift. Pronounced tectonitim in the Daniel's Harbour area pmduced 

abundant exposure surfaces. Lminites sccrated during intervening, 

stable periods of gradual rubsidenos. Tha thick, upwed decpeniw unit 

at the top of the lover &r reflected regional deepening prior to 

faulting and uplift of the platfom, a predicted effect of the migration 

through the area of a peripheral bulge during plate convergence (Quinlan 

and Beaumont, 19841.

The Buetatic Model - Eurtany' is a1so.a viable and likely cause 

of this stratigraphy. Local tectanim on a biock-faulted platform does 

not explain the extensive correlation of the stratigraphy 200 lun to the 

south nor daes it adequately account for rhythmic see level flustuo- 

Lions. Three critsria inply that eustasy piayad n role. Firstly, 

correlation of the stratigraphy suggests that sea level flnctuations 

affected the entire platform. Secondly, high to modsrate amplitude sea 

level oscillation related to clhts-controlled eustesy is a logical 

means of forming emsional caps on repeatad subtidallintertidal beds 

(Read et al., 1386; oo1dh-r et nl., 1987). Thirdly, the periodicity 

end duration of deepening upward sequences comperes to long period 

Wilankovitoh rhythm of 100,000 to 300,000 years (Imbrie and Imbrie, 

1980; Hardie, 1986). 

Under a =static scanario a typical sequenes would be interpreted 

pe follows: Lamldte units aosreted as sedimentation kept pace with a 

gradual eurtath rise. Burrowed beds onlapped the platform during sea 

level maxim. Hderare qlitude, short period oscillations associated 

with these maxim caused repeated flooding and emergsnca of the plat- 

fom. erosional caps and breccia bsdr at tops of subtidal units 

developed during the fall of the long period sea level oyctes and 

probab>[ lasted thmvghovt the minh. Peritidal sedimentation was 

renewed as sea level rise in the out- platform restored pmdustion 

of carbonate sediment. This sedimentation phase m n l y began after 

flooding when ewparite precipitation and silicis md deposition was 

'. EUS~~SY, 

here, elso pertains to large scale fluctuations of see level 

on the eraton that result from teetonism nio iisartssy and is not necessarily a 

world-vide phennma. 

101

follow~d by accretion of laminitas. ~epeated Ei!mding and niliois md 

102 

depaaition interrupted lanunite depsltion during short period sea level 

wcillatlons. thick aeepening upard ""it .t the top the lDwer 

mder remrded a high wlituds cycle prior to the occurrence of the 

st. Gwrqe Unconfomity, an anmalous eustatic minimum. 

~n conclusion, the stratigiaphy of the laver mber is in~cr- 

preted to be the result of dined tectonic end eustatic effects. 

Regional testonism profoundly afffected the platfm at the end of the 

Berly Ordovician (J-s et al., 1988). Shallowing upward of the upper 

st. Gaorge Group, a first order cycle, records decreased subsidence 

~lativs to the rate of sadiwntation. This is a natural phsnmnon of 

m t platform (Wilson, 1915), but in this saae gradual uplift OF the 

tilamin during lithospheric flaxure pmbably generated shoaling and 

famtion of the St. George Unconfomity (Knlght et al., in press). The 

deepening upward ssmnd order sequences record long period rhythms which 

ars interpreted to record sea level fluctuation. from climate-mntmlled 

Rilmko~itch cycles or pulsar of seismicity. The climate-controlled 

(eustatic) madel is preferred for several reasons;: (1) the widespread 

nature of the cycles independent of sedimantstion rates end facie= 

changes, (I) repeated rubtidal beds with erosionsi saps are r-ly 

explained by high to maderate wlituae sea level oseilletionr end (3) 

the estimated periodicity of there sequences is comparable to long 

period (100,000 to 300,000 year) climatic cycle=. Third order metre- 

scale, shallwing cycler represent normal sedbntary pmesses of 

flmding and acoretion. 

Tectonism altered there processes in several ways: (1) gradual

nwv-nt along ~ynredinent~~y faults resultid in, local Ehanqea in 

107 

subsidence rates and facie., (2) arrestea tws of semnd and Lhird order 

cyoles possibly reflect slrbtle uplift of the platform which affected 

hte stager or accretion cycles and (3) the abundant breccia, and 

erosional surfsces in the mine area suggest that they ore the pmnounced 

effects of local tetonic mvemenks. 

4.3.1 nature and Distribution of Lithologiss 

The middle member, in contrast to the uniformly thick lwer mnber, 

varies in thickness frm 70 mover strvccural depressions to 7 mat 

Table Point to less than 2 a in many areas (Figs. 4.6, 4.7). The 

greatest thicknesses fill areas of solution collapse or dwn faulting. 

Areas of solution collapse ere underlain by rock-matrix breccia. (see 

Chapter 7). These subsurface karst features fill former cams and occur 

along faults and are locally stratabound within the Catoshe Fornnlion 

(Fig. 4.6). In the mine area, recognition of the middle neber is 

significant. It narks the beginning of significant faulting end 

ksrdification of the platform and indicetss that these pmesssa began 

prior to the regional unsonfomity as sedimentation continued. 

tithologies sre identical to those of the lover nanber. Bum- 

nottled beds are intercalated with tan dololminites and dark gray, 

cryptalgal laminites. Netre-scals burror-mttled beds shallow upwards 

into lminite caps, in contrast to the lover member where such caps are 

unmn. cherts are locally abundant, particularly at the top of the

&er. Plirck brm-wttied feci-3 in th; thiokest sections ars 

laterally transitional to dalolminitr faciee where the mder thins 

(Pig. '1.6). Burrov-mttlsd beds are bracciated and thinned near faults 

and karst breccia% (Fig. 1.6). 

4.3.2 DeposltW Envbmnt 

I n.1 

Pe~itid.1 deposits similar to those of the laver member fomd a 1 

L'o 10 m-thick venear over the platform in this region. Ontewraneous 

faults and subsurface karst created subaidim~ areas a kilmetre or mre 

in width. Peritidal sediments thet filled these areas imply thet 

sedbntation rate kept pace with subsidence. Lacvl subsidence, 

hovwcr, was great enough to allow local dcvelcpment of subtidal. 

burrowed fades. 

,4.4 The St. E.ow Onmnfodty 

The exiatsnce of a tegegiinal vncanfornity was not fully rsenjniizeh 

until the stratigraphy and sedimentology of the drill care was carefully 

exmined. This led toe re-exmination end re-interpretation of ths 

Table Point type section. The vnconfomity is e subtle contact in mst 

drill core end a disconfomity at Table Point. In the mine area, tan, 

massive to imdnated dolostones of the middle owher arm abruptly 

overlain either by il thin quartz pebble conglnerste, a thin green shale 

or massive, blue-gray dolostone. At d able Point an lrreguler sudase 

cuts d m into tan hinitea with abundant chert ndles end is werlain 

by a 50 m-thick shale bed.

Piqure 4.6 Stratigraphy of the Upper St. (ieorqe Group aomss e Daline 

'Yhe lwer member of the aguathuna Fornation drops doun over the 

Trout Idke Rmk-Matrix Beeocie (a subsurfsee karst bmeoia) in the upper 

cetmhe Formation llmation in Ei9.1.4). Gradual thickening of the 

middle Wsr fm 1 to 60 rn cotresponds to the lateral extent of 

~tratabound oligomict breecias (partial dissolution of beds of the upper 

atache Fornation). B u r 4 beds of the lniddle &er occur lmslly 

within these areas. The upper menher geneally fa- a 7 nrthick veneer 

over the St. George Unconfomity, but it abruptly th!ckens up to 50 m 

where it fills sinkhole troughs, 50 to 100 n wide and up to 1000 n long, 

where the underlying menbrr ate down-faulted and collapsed to form 

plmiot breeciss in fomer eaves in the Catmhe h mtion. The middle 

member i s reduced in thickness to 5 to 10 in of solution bressias beneath 

these sinkholes. argillaceous limb tone^ with fossil debris and 

abundant conodonts -rise the sinmole deposits.

a ag- 

3 ;- 

% g- 

a II 

Hi- 

; !- 

z 

w o 

E 3 g 5 

s'c !$ 

$2 02 

106

Figure d.1 Iaopach Map of the Middle and Upper Members of the 

nguathuna Porntation over e Ooline and Structural Oepression to the 

southwest 

an isowoh olap between two delinite erratigraphic markers, the 

"worms" mrker and the base of the Table Point Pomtim, demonstrates 

the thickness variation of the middle and uppr mlnbers of the nguathuna 

Formtion. Thicknessas greater than 30 m f ill areas of solution 

collapse. %icknesses between 21 and 30 m dsfine both the subsided 30 

to loo wdde rim of the collapse mne and, also, a broed area of 

strucLural subsidence to the southwest of the collapse zone. Pipre 4.2 

givss a regional prepcorive.

srghlricant emsional relief of up t? 10 m oemrs al Aguathuna 

Quarry at Port au Port and in the nine area. Lt Pguathuna. Quarry an 

erosional surface, 7 m deep, cuts into the gently folded middle mehr 

and is filled vith lhatonaa cwvel with the upper nelnber (Jmr et 

al., 1900; stait, 1988). In the mine area the lower and middle menbers 

10'1 

are tilted and aisplaced along Eaults aricnted northeast-southweat (Pig. 

4.1). A eubhorieontel, erasianal surface bevels the stratigraphy north 

of the mine and locally cuts down mre than 10 m into the lower menher. 

The lwar menher dramtically disappears north of the Torrent River 

~avlt (Fig. 1.3). 35 h north of the ntine, where the unconfomity rests 

on tho Catache Formation (Knight, 1985; Knight et al., in press). 

several sinkholes occur on the unconfadty surface in the mins 

area. They are rteep-sided, elongate troughs, 100 m vide x 1000 rn long 

x 50 in deep, which occur over fault-controlled mck-matrix breccias 

(1-14 4.6). similar aridhlas are drrunented in east Tennasrse 

(Laurence, 1944; widqs, 1955). 

The history of the unconfomity is interpreted as follows: After 

deposition of the middle &ST the platfam was gently folded and 

faulted. Contemporaneous or subsequent erosion truncated the defomd 

stratigraphy and left a micmtapogrophy vhich varied frm a nesrly 

level Msted surface to valleys mre than 7 rn in relief. Local 

solution collapse wer fault-related caves created sin!&ole tmugha up 

to 50 m deep.

4.5 The muember 

4.5.1 mtmductim 

A distinctive unit of blue-gray. partly calcarwua. finely crystal- 

line dolostone cowL'ises the upper 6 to is m of the Iguathuna Formation. 

Abundant microfossils indicate a distinct difference between the llpper 

ana unaerlying &rr of ths Aguathune Forniltion. The unlt locally 

thickens up to 60 m where it fills in sinkholes. In the mine orea i t 

resb disconfonnably upon either the middle rmhr or the upper part of 

the lower m d r . At Port au Choix it liar on the mtoohe Forration. A 

basal~artz -1s songl-rate collects the sroslonal residues aE the 

unconfomity. 

The biostratigraphy indicates a t k break oE 1 to 3 ma. at the 

uneonformity (refer to section 2.3.6). The upper mnber contains e 

Nhitemckian fauna of abundant conodonta, rare trilobites, brachiow& 

and ostracodr (Williams et al., 1987; Stait, 1988). These fossils are 

the sms age as those in the basal Table Point Porntion. One or mre 

conoaont eones are missing between the upper menber and underlying 

strata (Stait, 1988). me unconfornity, thus, probably represents en 

hiatus of 1 or. mre million yeus. Differences in sonodont eevenblegea 

in basal beds of the upper member in western Newfoundland also suggeet 

that these sediments diachmnously onlapped the unwnfonrity fma 

sinkholes in the mine area to the surmnding area and later over Purt 

au Choix (Stait, 1988). The yovngest onlap my be recorded near Cepe 

Noman and Burnt Island, Pistolet Bay where the Table Wint Polmation 

locally overlies the Catoche Formation (Might et al., in press).

(1) Massive, finely crvstal1ir.e dolostone - There blue-gray, partly 

calcareous beds, 1 tu 3 m thick, constitute most of the upper m&er. 

Tilay contain s very shallow mrine Cauna of abundant oonodonts and the 

minor mvofeuna noted above. The beds have dark gray to slightly 

argillaceous bases whioh grade upwards in colour to light gray &lo- 

atone. R feu beds are faintly bur--nattled. Vertical epifaunsl 

burrows and irregular solution I?) pits penetrate abrupt tops end are 

filled by overlying dad sedbnta. Pratt (1979) identifies sane of 

these dwellings as Di~locraterion. m e surfacer are desiccation- 

cracked and emded. 

These beds are interpreted to have been deposited in intertidal sn- 

vironments. The eonodnnt-rich sediment probably originated in the 

subtidal or intertidal zmes and was transported onto high flats during 

storms. Bed tow were lithified, burmued, dasiccsted and karstified in 

the lower intertidal to rhallov subtidal zones (at. Persian Gulf, Shinn. 

1986). 

(2) Gray-green dolmitic shales - Wsiocatian-cracked, quartz silt- 

rich shales, 1 to 50 m thick, nrs similar to shales of the lover 

Wer. They were deposited during flooding of tidal flats. 

(3) Nodular linestmes - One or two thin, 10 to 20 nn bioclastic 

wackestones similar to those in the overlying Table mint Pornstion 

war looally. They contain trilobites and ostracods and probably 

accwlated in the subtidal zone. 

(4) Pebbl~ 

mudstones, wart= san&tones and wartz ~sbble 

coo- 

- Pebbly mudstone and sandstone beds (PI. 4.3a,b,c) possess a

lag of millinetre to centirnetre-sized chert and dolostone pobbles. 

The clorts are dispersed and fine upwards in the lower 1 to 10 cm of 

coarse quartz sandstones or massive dolostone beds. pnartz pebble eon- 

glmerates (PI. 4.3~) up to 1 n thick occur laally on the unconfarmlty. 

me =lasts teach 6 cn in dimter. 

Provenanca of the clasts is generally local. Fine doloatone and 

chert olasts are identical to underlying lithalogies (PI. 1.6a). 

Hapick (1980, however, reported exotic oolitic and netwrphic ciasts. 

15r quartz pebbles arc interpreted to be residual naterial Emn 

emrion at the unmnfamity. The clasts were entrained in stam Iloods 

end deposited within graded pebbly mudstones and sandsb,nea. mn- 

glornerater ecc-lated along emsional ascarptents (James et sl., 19RB). 

mtic clasta auggest that seasonal rivers or fl& carried sediment 

wer 100 h from the craton. 

. (5) Dark may, argillaceous limestone - This lithology occurs 

locally within sin2&oles. The basal beds are massive argillitss. They 

I I.! 

are overlain by finely laminated linestoner, up to 50 la thick, which arc 

millimetre-scale, graded rilt-mud rhythnirtas. Burrwr are absent. Thin 

skeletal gralnstones of ostracod fragment* and intrsclast waokestones 

are intercalated with the rhythnirtes. The laminations exhibit variable 

inclinations in contrast to uniform dips of the underlying stratigraphy. 

Dark muas llnd debris of fossils and intraclasts ere interpreted to 

have filled terrestrial to subtidal sinkholer along karsted fault zones. 

Anaembic conditions or rapid redilaentation inhibited bsnthonis organ- 

isms. The rhytbmitea pmbably acsmleted slwly as thln seasonal 

deposlts and slumped as faulting and salvtion collapse occurred in the

plate 4.3 chert Pebble Beds above the St. George Unsonfomity 

,up is tward the top af the page.) 

a. ~uertz pebble eooglwrares at the bese of the Hiddle ordoviolan 

Table point Formation overlie the St. George Unconfonnity at liguathuna 

puany. 2 a chert nodules occur just beneeth thib Burface in the 

underlying dololminites of the middle member of the Aguathune m a - 

tion, mey are the main rmee of the pebbles. The pen measures 13.5 

om. 

b. Quartz and dolostonr pebbles are dispersed in fine quartz sands 

which are intermixed with dolostone (originally mudstone). II centi- 

metre-thick coarse pebble lag fomr the irregular base of e bad appmxi- 

rnetely 3 rn ahve the umnfomity. Six beds ~Mlar to this one oocur 

in the lover 5 n of the upper Rwber st Wle mint. The scals is in 

centhetrer. 

c. puartz pebble cooglmratt f m the bese of the upper d e r at 

Portland Creek Pond (collected by Ian Knighc). The scale is in aenti- 

metIeS.

4.5.3 Distributh of Liththolcgies 

Althmgh massive ddoptana comprises most of the upper &ere 

subtidal nodular, biwlsst~c ljmstom, stom dwsltr of pebbly 

loudstme or beds of dark gray mudstone form thc lmer portions of 

thenember. Quarts pebbles are especially cannon at the base of ths 

upper member, but at Table Point they appear at the base of 6 dolostone 

bsde in the lover 5 n of the member. Desiccation aracks and shale 

Orapes, 3s veil as burrows and microkarst occur on the upper 8urhc.s of 

some dolortone beds. Unlue the lauer menbar, beds and surface features 

can not be correlated laterally. 

Typical mssive dolostones ere lacally transitional into sinkhole 

deposits d argillaoeoua limestone where the uwsr meuber thickens f m 

7, to 50 m. Lithologies within sinkholes change upwards fmol "an-marine 

I?) erqillite at ths base to middle portions of marine rhythiter with 

intercalations of bioclerts end intraclasts, ell capped by rtylolitic 

limestones and typical massive dolastones. 

4.5.4 oepasiticn~l mimmm 

Sediments of the upper member of the Aguathuns Formation were 

deposited during the Middle Ordovician transgression of the St. eeorga 

Unconfomity. The thicksst deposits accreted over faults or collapse 

brecciar where lmel ponded sinkholes filled with black muds. The 

unsonf-ity was locally veneered by chert sand and gravel, the erosion- 

al residue of t+e St. George Unsonfomity. and this was revorkd by mo-

lnneine sheet flmds over the hard carbonate lendscilpe. wring marina 

traniqreasion of the platform, however, lmrine stom processes incar- 

paratsd the quartz pebbles into muddy peritidai sedinents. 'he muddy 

tidal flats diachronovsly onlapped an irregular to&qraphy. 'The tidal 

flats accreted in repeated episodes of deposition of 1 to 3 n of nud in 

tha intertidal zone. Intermittent sxposure of uppor surfaces lct't mud 

cracks andfor a ewer of vind-blown silt. Wony of these surfacsr wee 

ilb 

lithified end burrowed by organisms during marine $ubmersian and kersted 

during mergence in the intertidal zona. Rare subtidal bioclaatic 

uackestones oovered theas surfaces during the deepest suhrsion of the 

flats. 

4.6 The Ia*er Table Emkt Pmmdtion 

4.6.1 Intrduotirm 

The lower 50 metres of the Tabls Point Formation contains distinc- 

tive light grey fenestral limestones vhioh serve to distinguish it E m 

overlying nodular or Rlbbly, kqely subtidal, limestones. This unit is 

celled the Spring Inlst Umber (Pass and same=, 1987). 

4.6.2 Stratigraphic Harkem 

seven key laterally extensive beds are used for correlation in the 

~anlel's Herbovr nine area. The position of the seven beds relative to 

the bese of the fomtion is as follows: 

(1) two thin nodular limestones at the bare of the formation; 

(2) a blVraV mttled bed a t 6 to 8 m;

(3) a Eenestral unit at 12 to 17 mu; " 

(4) thick nodular strata at I1 to 30 n; 

(5) a chert horizon at 2s m; 

(6) a Fenestral unit at 30 to 50 m; 

(11 e thin cslcarwvs sandstone at 50 metres in DOR 519 that con 

be correlated with the ~abie point section. 

4.6.3 Litholqies 

Three lithologies dominate the spring Inlet Mder. 

(1) Nodular lh3atones - Nodular lineatones consist oI ccntimotre- 

thick Imps or nodules of biwlestic uackestone, separated by 

millinetrs-thin dolrrmitized argillaceous laminations and thin beds. 

Thsy are organized into nodular or Pitted fabrics (Coniglio, 1985). A 

restricted, low diversity Pwna of leperditid ostracods, high-spired 

gastmpada, braohiopads and comdonts imply that the ccehnates sccunu- 

lated in very shallw water (Stouge, 1980; Ross and 3ma.1987). The 

fossilifemus beds are interpreted to be very shallw subtidal where 

marine cementation and early cornaction dined to :om the nodular 

fabric (Jones e t a1, 1919; Plugel, 1982; Coniglio, 1985; Stenzel, in 

Prep. I. 

(2) Burwed Lime mudstonee - Massive, thomughly burroued line 

mudstone beds are 1 to 2 n thick. Light-coiourad calcite cements 

highlight aubvartlcsl tubular trace Fossils. These beds are similar to 

the shallow subtidal Thalassinoides lithology 01 the Aguethune Porn- 

tion. 

(3) Fenestral lim mdstone - Massive, stylolitic line mudatones

1.6.5 Depeitional Inyimmsnt " 

The Spring Inlet Member uecumulatrd on a shallow subtidal to 

writidill platlono inhabited by z low dlvcc;ily, ravlrictcd voter faunib. 

Drill hole infomtion suggests that early broed, prltldal fiats 

, evolved into isolated peritidal islands a kilomtce or aura in width. 

'This micmtopography of broad L'idal [lata und intcrvsnlt~g xvbtidal 

1-ns was probably cantroiled by grwth faults Istcnrcl, in prop.). 

The tidal fiats accreted In shallowing upward scqucnses Ircn subtidal 

nodulu wmltestones to burrawd nudstonw, and peritidal fenestrai 

11" 

msdstonas and weckestoner. Dssiccation cracks and thin daiolilminitcs in 

the letter fecies formed during intermittent rxposuce. The lvck of 

prvnsive dolomitieation and evidence of evaporite. plus the abumdonce 

of ferastrae suggests that these tidal flats were prabably humid and not 

as arid or restri~ted as in the Aguathuna Formation (Grover and Raed, 

1978; s. stenzel, pars. corn. 1988; Knight, in press). Thc flats were 

Eventually drovned as platform subsidence exceeded ths rate of acdimn- 

tation, so that the sprlng Inlet n&r was overlain by subtidal, 

fossilifemwr shelf limestone of the upper Table mint Porntion. 

4.7 summm of the Scdirntsry and Stratigraphic BMlutim of ths Uppar 

st. Gmvp and Lver l&h mint Fmmtirm 

During deposition of the upper St. G-oqe Omup the Lower Paleozoic 

platfor. in Newfoundland shallow4 upwards fm an open subtidel shelf 

(Cstoche Pamtionl to expansive peritidal flats (the Aguothuna Yam- 

ticn) as sedimentation outpaced e slowed rate of aubaidense. Eustatic

sea 1ev.l fa11 andlor regional uplift th& drmltically loft an enerqsqsat 

plstfom (St. George Unconfomity) for as much as i to 3 ma. Prior lo 

and during emergence surface end subsurlacr karst and block faulting 

1;.n 

fomd an irregular, locally collapsed topwrephy. Increased subsidence 

end eustatio rise cmbined to gradually submerge the plotfom at rha end 

of this tina. During this =rib onlap peritidal dolmitixed mas of 

the upper menber of the Aguathuna Pamation were blnnksted by the 

peritidal to shallw subtidal Table mint Porntion. 

The gradual shallowing of tha platfam in the late Early ordavicion 

is described in four stager. 

(I) muddy, nodular limestones of the middle Catoche Formation 

accumulated on a low energy, open shelf during mimum marine 

submergence. Deep and ahallw water fauna irterdngled to fom a 

diverse omnity around thriving algal-sponge biohemr, while intermit- 

tent stom waves entrained thin beds of intreelasts and skeletal debris. 

Period. of turbidity interrupted the activity of organisms. 

(2) The transition fm the middle to uwr Wtoche Formation was 

abrupt as shoaling above a oritical depth dissipated the enemy of storm 

wavss and currents. This change drmstiselly affected sediments and 

organisms. The and of deposition of skeletal, intraslastic rudstaner 

resulted frm dhinished biohems and stom "eve erosion. A l w 

diversity nnmnrnity of shallw water orgenims thomughly rrrarked the 

fossiliferous mds as the rate of sedimentation s1-d end waters 

remined relatively clear. 

(3) Grainy pelaidal sediments and shallw water mudstones becam 

intelcalated with the burwed skeletal muds lmrta Bay Merber, Cdoche

Fo!.matiun). The sc3inmts were deposited in distiqctive upward deeen- 

ing Eeqllencor: a posaible response to high frequency sea lavci ossiiiu- 

Lions or insreoritlg amplitude. baqe plenirpirai gastmpadr and large 

sort-bodied dsposit feeders characterized a restricted shullw water 

fauna. Abundant peloids acounulated in tho very shailov subtidal to 

intertidal &ones where algae, burrowers and edrly diagcnoris produced 

numerous grains. 

(11 The pletfom ahailowad upwards abruptly fmn tha rhailw-water, 

buzrowed €lots 'f the Caloche ~ornstion to vest peritidal eiots or Lhc 

lower olelnber of ine Aguathuna Pornation. These flats passed through 

reourring eurtatis and/or tectonic-controlled cycles. 'I'he cycles bagan 

111 

UiLh emergence; followed by supratidal ~Edinentation during a atetic am 

levpl; continued with "puvad deepening and law intertidal to subtidal 

onlap during a phase of see level rise; succeeded by repeated emergence 

.of subt:dal [late during oabrate to high amplitude sea level osoilla- 

Lions; and concluded with a return to mergence. 

'The sediments QP the Aguethune mmtion reflect e restricted to 

arid environment. The firn, mddy subtidal substrates, unlike ones in 

the Catoche Formtian, Hers depply excavated by networks af M- 

- 

noider-type burmws. Wind-blwn silts and evaporite8 covered intemit- 

tently flooded subserial surfsces. Contenporanl silica replaced 

evaparitrs and precipitated nodules, and was emded to €om pebble 

conglmretes. Oolnnitized lminitea end mds with desis,cation sra& 

mered the supratidal flats. 

At the close of the Early Ordovician mjor sustatic regression 

andlor tectonic uplift left a gently folded, faulted and karstad

surf%ce, the St. George Unconfomity. Tectonic loading during plats 

canvergence flexed the lithosphere and fragmented and locally upliftod 

the helat*orn IJmee et el., 1988). Prior to the marine regrerdon, 

testonism and subsurface karst formed gradually subsiding structural 

' depressiono, which were filled by peritidai deposits of the middle 

h e r of the Aguathulla Fowlion. During s hiatus of up to 3 ma., 

tectonlsm warped, tilted end faulted the platform, then erosion bevelled 

the stratigraphy and left a surface of relatively lar relicf rovered by 

chwt pebble urnglomeratou. The surface locally collapsed above fsult- 

.controlled subsurface cevea to form sinkholes as mush as 50 m daep. 

Near the bsginning of the Middle Ordovician, regional subsidence 

and possible eustatic sea level rise corbined to produes gradual marine 

onlap. A unifann, 7 to 15 m thick, veneer of wry shallow subtidsl to 

peritidal mds (the upper menbet of the Aguathuna Fornation) incorpor- 

kted quartz clests Era. the emsionai aurfase. U msaio of mud flats 

diechronously covered the uaconfarollty, locally highiighted by thick 

fillings of sinkholes by rvbtidsi rhythiter. 

he mnfo~mably overlying Spring Inlet Heder of the Table mint 

122 

omt ti on covsed of shallo~ subtidsl to paritids1 sediment., covered s 

fault-controlled microtgeogrsphy of bmed tidal flats end subtidal 

leywns and onlapped remaining highs of the St. Geoqe Unconformity 

(nlfght, 1986, 1987). Shallowing "ward packages of nodular to burrowed 

and fenastral wackestonea end mdstones lacked the pervasive dolomiti- 

zation and evaporite. of the arid, high peritidal flats of the Uguathuna 

f or mat ion. The entire platform submerged at the top of the Spring Inlet 

~enmer as lnqrsnsing rates of subsidence preceded later toundoring of

the platform into a foredeep (Stenzel and Jmr, 1987, 1988). 

In conclusion, the sedimentary history of the St. George Group laid 

the framework for post-depositional rvents. Ulternating mudstone and 

grainatone beds in the upper Catoche Fomtion established an 

anisotropic rock mass that strongly influenced selective dolmitirstion, 

defomtion and fluid movement. The Uguathune Formation formed a finely 

clybtslline ceprosk over the Catoche Pornation. Northeast-tranding 

faults which were to belong-lived, influential structures bagon to 

alter the pletfom with the focmation of local karat features, erosional 

horrts and sedimentary grabens.

In Pert I11 the petmgrapnlc and g-hmical attrllutes a1 dolun- 

ites, sulphides and sulphates are described. Petrographic, rtrati- 

graphic and structural relationrh~p are utilized to define a clear 

paragenetic sequence of diagenitlc evsnls. The dolmithatiun history 

can be separated into e near-surface phase preceding karst formation, an 

early burial stage contsmpmaneous with the develowent of stylolites, a 

deep and late burial phase characterized by hydmtheml dolomites and 

late fault-relatsd aolomitiration. sulphlds precipitation is intlnately 

related with the hydrothermal dolomites. 

The sulphide history includes 

an early end Iate ore stage and post-ore precipitation ol galena end 

euhadral sphalerite. White, hydrothema1 dolomites and mlphates 

precipitated in the post-ore stage.

This chapter describes the dtrogrsphic character and 

geochemistry of the dolomite crystal types, evidencs for their 

relative age, their position in the sequence of events and 

interpntstions d the environment8 in which they crystalliaed. 

This desoription Lorn ths basis for later discussion of the evolution 

of dolostones, breccias and sulphide bodies. 

The upper St. George Group is extensively dololaitised at Oaniel'a 

Harbour from chm bas2 of the peloidal nrndrer of the Catochc mrnstion up 

through the entire nguethunp. mnnation (Fig. 1.4). 'Phe variety of 

dolostone bodies whioh comprise the upper St. George Grmp includs 

stratigraphic dolortones of the Nuathuna Porntion, rock-autrix 

breccies, dolostone mottles and beds m limestone, atrathund coarse 

dolostones (preudobbrffoie end coarse sparry dolostone) and discordant 

dolostones (Fig. 1.4). More than one type of dolomite mnatitutes mst 

dolostones. Variable cryrLal textures, zoned crystals, ghost fabrics, 

veins and cemented dolestone br~ccier collectively record these multiple 

types of dolomite. 

The constituent doldte crystals are examined to establish mn- 

straints on the relative age and seymenos of crystallization. The tern 

doldte, in this study, refers to crystals and to mnposltsr 

of the minsral. Seven dolomite types are recognized bred on

127 

or! sLsnd,~rd putlqmphic and cntllodoluminescent observationc. A & 

% in defined her" us one or more cryrtoi foinu;, e.g. microcrystal- 

line, wdiun-sized dds or noddle doiomiLc, unillcd'by apccirsc 

caLllodoiurineecmt (CL) pro,ertrca, distincLivc isotopic values and, in 

1.m. C~WCS, a ehoracteristic trace clemsnt chemistry ('rable 5.1). 

RriaLionships between the Lypcs iudicale that each rcpresenLo a distincl 

gnneriltion. 'l'ha distribution of thc'scven &lamite types in the various 

doloetann badiea is shown in Fig. 5.1. The d>losLonc are described and 

iotcrprstcd ~n Parts I and 5. 

mtwraphi- descriptions comoly use qualitative terms la refer 

Lo spccific sizes of orystsls and Fares. Crystal sizas ere defined as 

folio~s: rni~ro~ry~tallin~ (to mail to menrurel, very Einc (2 Lo 50 pm), 

rinn (50 to 200 ~n). medium 1200 to 500 w), conrae 1500 lup to I m) and 

megocryatalline (groater Lhan I m). The classific&tion of pore types 

and sizes is bnsed on Choquettc and Pray (1970). Cavities, caves and 

CBYOL.OS mmnly =an f it a h-n, but can be as snsli as 25 cn-high 

openings. Urge Regapores renga from 3 to 25 cm in dimter. small 

mcgeporer vary in size from 0.4 to 3 cn. nesopres measure betwesn 50 

IM and 4 m, end micropores are the Iinest holes. 

CrrJtal types were identified by transmitted light petrography. 

cathodoluminesoence and staining for ferroan dolomites with potassium 

Eerricyanide. Doiomite stoichimtry (wle percent Cam,) was measured 

on a Phillips x-ray diffractornetex with N-K radiation at a scanning 

speed of one half degreelminute. The posltion of d(104) peaks of

dolomite powders were determined relative to the d(200) peaks of 

included powders of en NeCl standard. he position of the d(104) pook 

measued ths m unt of MgCO, substitution into the carbonate lattice 

with a precision of 0.02 ml % nagnesium (Goldsmith and Graf, 1958; 

Blatt, Middleton and Hurray, 1912). , 

Chemical ccqosition of the dolostones was surveyed sither in this 

study or previously by neutron activation analyses for 22 olajar and 

128 

trace elements (Diilon, 1978); mltialemant ICP analyses for YJ elanlent8 

(by Ch-r Ltd.): non-quantitative analyras from the EDAX back scatter 

electron image on the SEN; and atnnis absorption analysss of mjor 

elemerlte. Individual crystal types were analyzed for nine elmntr ICa, 

w, Fa. In, na, sr, si, u1, P) by e focused electron beam of 2 wn on a 

JEoL Jm.50 electron microprobe. A carbonate standard was calibrated 

relative to knwn values fm crystal. of dolomite, garnet, rhodonlte, 

celsstite and apatite. The squipnt operated with a 15 KV beam, 

specimen arrant of 22 nannoweree and o counting the of 30 seconds or 

30,000 counta. The nAGIC program corrected the data. Carbon and 

oxygen isotopes of 49 swles were analyzed by Teledyne Isotopes INw 

Jersey) and reported in conventional delta notation in parts per mil 

(olw) versus the PDB-1 standard. Precision for both 6' 'C and 6'"O is 

0.1 alw. an engravers twl was utilized to s wle nilli!oetre-sized 

areas on dolostoner and negasryrtals. ~mgenewr areas of similar 

crybtal tme8 were selected in fine to medium crystalline dolostones. 

The wonition and h-enization t-ratures of fluid inclusions 

ware measured by freezing end heating then on a Fiuid Inc. di~itei unit. 

The calibration of the unit was tested on known synthetic and natural

figure 5.1 Distribution of Dolmitc Types 

The seven designated doldnire types are variously distributed in 

the upper St. George Group. Dlanite I is abundant in the Apathuna 

Fannation and rock-matrix breccias and is cnomnly intermixed with and 

ouerprintad by Dolmites I1 and 111. Wlmites I1 end I11 cwriae 

dolastone lnottles in lmstones and fom abundant zoned crystals in 

rock-matrix breccia.. Wlaites Iv, v end VI make up coarse strataboun-' 

dolortones in the upper Cetoche Pornation. These doldtes cmonly 

ovelprlnt mettles d Dlmitea 11 and 111. Wlonite VII cwriaea late 

feult-re: iLcJ dolostones.

~ m p l e with ~ varying Nacl r 11,0 compositions. 11-onizetion tempera- 

tures were not corrected for pressure. 

5.3 Dolomite me I - Ilon-lminesoent oiomtalline &Mte 

Petrwraphv and Diatributibn - Very line to Pinc, dusky, ouhcdrol 

crystals gmu dose togerhsr and are thinnly parted by bran, to black 

interstitial roatari.1 (Pl. 5.3b). All tagether the crystals constitute 

a gray-brovn mismcrystalline rock. This significant doloatone com- 

prises most of the Aguarhuna Fornetion, scattered beds of the catoche 

Pornation and portions of rock-matrix breccia*. Crystal sizes vary 

I I: 

ascoreing to the lithology: 10 to 20 w in dolalolpinites; 20 to 30 um in 

burmet beds of the Muathum Pornation (PI. S.la,d); 10 to 100 )ua in 

m,*rtone lithologies of the Cetoche Formation (PI. 5.ie); and 20 to 50 

w in matrix patches a? &-matrix br-les. 

Cathodaluminessence - Micmcrystalline dolomites are weak to nan- 

lminessent (PI. 5.la,d). Fine crystals which replace Catocha nud- 

stoner, however, exhibit purple CL (Pl. 5.le). 

Geachernistry - These b ldtes have distinctively heavy S'*O PDB 

valusa of around -4.S 0100 canpared to other crystal types (Pig. 5.2, 

Appendix A). These values are 3 to 4 par mil heevier than St. George 

limatones 8"c values of -0.5 to -1.5 olw PUB are similar to these 

limeatones (Pig. 5.2, appendix A). 

The stoichlometric dolomites have a d,.,. peek at 2.805 m which

a. A burmwed dolostone E m the Agvethuna Pamtion with very fine 

crystals of dull CL mlanita I (a) and patches of fine-sized, bluish to 

pink r hds of Dolamite I1 (b). Extrsmely fine-sized cqstall of orange 

CL Dolomite I11 ere dissminated throughout. 1 m scale. 

b. nedim-sized crystals of Uolmite I1 canpriae dolortone mttles in 

an upper mtoche linestone, 20 n below the top of the formation in WH 

1254. They have purple a corer and wer~mwths ol pink ffi dolonite 

which a1w partially replaces the w ee. Caleita In the upper pcvtion 

of the photmicmgraph is non-loninescent. 1 m scale. 

c. mnd rhorobs of Wlonite I1 oceur within etylanottles in the middle 

catmhe Porntion, 10 m belev the top of the fomtion in DDH 631. 

These crystals, unlb those in S.lb, have bright sores and dark ferman 

midsections. Pbundant detrital feldspars (blue CL) arc conceotrated in 

the dolastone mttle end alon~ the rtylolite. 1 m scale. 

d. Hedim-sized zoned cry~talD of Dolomite III replace the matrix of 

breccia beds in the Agathuna mmtion (W. 626, 84 m). Later wa- 

rmartz (blwkFk) partially replases these crystals. Weakly luminescent 

do la nit^ I on the left contains intercrystalline with pore saneat* of 

mlmite 111. 1 m scale.

*. purple tm crystals of blcmite 1 or'11 are cut by I>OZ"S fillod WiLh 

I37 

mned cemnts of Wlmite Ill. Isopachms c-ntr (1) line pores. l~lctk 

CL dolomite (2) which rims crystals of DolomiLe I1 in 5.lb farms initial 

cements after dis~olution. There dolomites replace a mudrtana bed in 

the upper Catocha Pomtlon (DDH 1254, 20 m b.u.m. 1 nn scale. 

f. 

~ en d ~olonrite IV overprints zoned rhmba with corer; uf uoimite 

Ir and rims of oolmite 111 (am). Gall red CL Dolomite V c-nts 

intemrystalline pores. These CL relics are preserved in a discordant 

dolortone beneath the east L Zone ore body in the middle Catoche 

Fomtion (DDH 1134, 55 m b.w.m. 1 m scale. 

g. 

Red a Dolomite IV is preserved in a patch where it overprints 

zoned rhnbs (armu) similar to those in P1. 5.lf. Coarse crystals of 

dull red CL Dolomite v surround the patch and also c-nt a late veinlet 

(arrow). Bright red CL Dolomite Y1 rims pore*. Sampls fmm uppr 

Catoche Formation a t Table Point. 1 m scale 

h. saddle Dolomite B (bright red CL) c~ergrous and cements cleavage of 

curved crystals of Saddle Dolomite A [dull red a). Non-lunincslnnt 

calcits cants late pores between crystals. Underground ample fmn 

the X zone. 1 m scale.

Plate 5.2 Diugenetio Calcites and early Uoinites 

a. Peloidal peckstone, upper Catoche Formation (WH 1254, 22 m 

b.v.n.). Hiomspar replaces the matrix. Pseudospar replaces a burrow 

in the upper loft. rurbid doloniter (11) replace another burrow in the 

lner right. 1 cm scale. 

b. Burmws and a veinlet occur in a miorite and are filled with 

pseudo~par and equant calcite cement. sample fran UDH 1251, 29 m b.u.m. 

1 nu acrlu. 

C. Burmwed wackestone, upper Catoche Porntion (DDH 66, 128 m). 

Early dolortone mttles form after brecciation of pseudospar (1). Later 

veinlets cut the mttles (I), ere cemented by calcite, E-cted (3) and 

truncates by ~tylolites. Dalswite I11 replaces calcite in veinlets and 

cents vertical pores along atylolites (4). 1 an scale. 

a. Pluid inclusions (armus) in early calcite aemnt in a veinlet vary 

in size I- 1 lo 10 m. Sample fran WH 1254, 20 m b.w.m. 25 ym 

scale.

Plate 5.3 Dolomites I and I1 

a. Dvlomita 11 occurs in rtylmttles (I) and burrows not associated 

with stylolites (2). Dolomite 111 locally replaces veinlets of calcite 

cent (3) which cut dolostone motrles. Upper Cetoche Formation, DDH 

1254, 10 m b.u.m. 1 cn scale. 

b. Fine crystals of Dolomite I are sr-isted with planar nicm- 

stylolites (arrars) in an early dolostons bed in the upper catoche 

Fornation (DDH, 19 m b.v.m.). 1 m scale. 

r;. Turbid do'.mites (11) occur clustered within a stylmttle on the 

right and as individual orystals along stylolites (1) and within ploidr 

larrar). There dolomites occur within a peloidsl packatone of the upper 

Catoche Formtion (WH 1254, 20 m b.w.n.). 1 m scale. 

d. Plne crystals of Dolomite I1 (arrow) replace the matrix that 

avrmunds brecciated pseudospar, attesting to the later origin of these 

o~ystals. The brecciation is related to karst frm adjacent mck-mtrix 

brecoiab. Upper Cstoche Pornation, DOH 56, 127 m. 1 m scale. 

e. Styloresidues displaced by Dolomite I1 crystals, generally euhedral 

chds (P1. 5.h m e under cathodolrrmin-acence) whicn ore partially 

corroded by pressure solution (mow). crystals cores pzerarve calcite 

Idark stains). Middle Catoohe Formation, WH 631, 49 m. 100 ~r. scale.

iillplies 50 mole m CaCO, (Appcsdix C). With l.hc cxcspliun ur Sr", Lruco 

elcmmts of imn, mnganere and sodium arc minor (Ap-ond~x 8). sr" 

COntcnt La highly variable hcLmall 89 and 240 ppm (Ilayniek, 1981). 

Il,lerrtilirl quartz and clay make up 3 Lo 5 uoigllt \ or the dolostoo~e 

(Appendix 8). 

I4U 

evidence a€ 'l'ining - Ricmcryatmilinc dolomites pre-dale orosiul! ur 

~nLreclasts in the Aguothuna Porawtion and [mgncnlu viLhin karsL- 

related mck-matrix breccia$ Li: hoth the Aguethuna and CaLacha Fornu- 

tions. This early age is mnfimcd by pra-compaction chert lloduics 

which preserve dolomito inclusions. All other dolmitc typcs cmse-rut, 

overgrow or replace Wlomite 1 (PI. 5.la.d.e). 

Internretation - Hicroeryrtaliine doimites replaced mudeta$mes at 

or near the original depositional surface. Uoiolminiles within lnetres 

of the St. Oeorge Unconfomity .,ere doimitized prior to incorporation 

into intrafomational conglmretes and subsxr!ace solution bressios. 

6'"o values, enriched 3 ;o 4 ojoo relative to iimstaner, pmbably 

resulted from fractionation in the =am near surface eovimmenl 

lciayton et al., 1968). The texture-specific dolonitization e~tensivciy 

aEfected shallow subtidal stratigraphic units as well .rs periLidal ones. 

1L was, therefore, not simply the result of evaporative reflux processes 

on the tidal flat (cf. Patterson end Kinsmsn, 1982). AlLcmative mdela 

suggeet dolmitization within mixing mner of saline and lnelsoric waters 

(Hanshaw e t el.. 1911; Und et al., 1915) or Eraa sea water in ground 

waters in the shallow subsurface (Sass and IOtz, 1982; Sims, 19m;

llgvre 5.7. Isotr,pe and Fluid Inclusion Data for early mimites 

and Calcites 

I'lot of 6'"O vs. 6'"C for primary linertones and early doimitea. 

1.imestones mntein -8 to -9 o/w 6'"O PDB and -1 to -1.5 o/oo 8"c 

(defined by 7 swlea, Comn, 1982; Hapick. 1984; this study). 

Dolmite I is enriched in B'"0 (-4.5 to -6) relat~ve to the limstonss 

(defined by 8 samples, Coron, 1982; Hapick, 1984; this study). 

mlmite I1 has a broad field of 6'"O valves (-5.5 to -1O)idefined by 15 

samples, Heyuick, 1984). Limitsd data on Dolmite III suggests limited 

variation of 6'"O valuer (-6 to -71, but considerable range in 6°C 

values (-0.5 to -3)lHaywirk. 1984). Dashed lines reprebent probable 

variations in water-msk ratios between initial dolomites with B'"0 

values of -4.5 a!w and fluids with initial 6'"o values of SHOW and +4 

O/W SNOW. In addition to data in Appendix A, Hawick (1984) analyred 

21 rm~lea of doiolminitea (mstly Dolomite I) and mottla dolomites and 

beds of Penssive (A) dolomite composed nartly of Dolomite IT. 

Pluld inelusion data f m want calcite cements in veinlets 

indicates that fluids mnt-raneous with mlmite I1 were hypersaline 

imlting temperatures of -la°C)(Appendix Fl. ma1 hmqonieetion 

tempratures of 85-C were probably readjusted during later burlal.

5.1 mlrmite Type I1 - Very fine to Wum cnlstallins, turbid 

dolomite with blue ta pink a 

Petrography and Dlstributiafi - Ubiquiloua rihic, Lutbjd c-u%tals 

OECUI in catoshe and Table point limestones as ccntimatrs-aired rnottier 

of fine to medium crystals, So to 300 w in size, and in mssive doio- 

stones of the hymathunn and cntoche Farnations as vary fine to Fino 

crystals, 5 to ZOO pm in size. Fine to lnediun crystals rino psrvadc 

~.ock-mtrIx breccias. Most crystals in ail acurrences have turbid 

mral wlth local calcite inciusions and clear rims (Pia.5.2e: 5.3e; 

5.na.b). 

The $most conspicuous dolomites aF this type cnprise dolostone 

mttles of the. llmstcnes (Haywick, 1984). Ciurlars of interlocking 

crystals replaa? burrows, the lnicritized rims of fossiltl and aieritic 

sew of insolwle residues along stylolites (Pis. 5.lb.c; 5.2n.c; 

5.3e.e.el. tndividual crystals occur erong reams of insoluble materiel 

and styiolites (PI. 5.3c.a); replacs mlsritic pelaids (91. 5.3~); and 

are disseminated in micrite and micmpar. The latter c,yatais mniy 

contain calcite inclusions and have irregular mayed bunaeries vith 

micmspar and pseudospar. These crystals are associated vitn ealcim- 

poor (dolomitic?) mrphous patoher which overprint micmapsr. Dirrml- 

nated crystals and patches and some mttles are separate from styla- 

lites, which are associated vith many af the nxrttle dolomites

' 

(PI. 5.3a,

Geuchenictr~ -Haywick (1884) rcglunaily survcyed oxygrn and cdrhon 

isotopes of sir samples of dolostone mttles ~n it. ceorpe limestones, 

145 

and 6,*0 values spa., a wide range F m -5.1 to -10.3 0100 MB (Fig. 5.2. 

Rppendix A). The dalomites vary frcm 9.0 per mil enrichment to 1.2 p r 

mil depletion in 6'"o relative to values of host limestones. seven 

regional ramplea of pervasivs doiortone have a sinlilar broad ranqe a€ 

6'"o values between -4.7 o/w PDB end -10.0 olw YOU (~aywick, 1384). 

Some of these dolostones have early dolamitized mttler vith anrlchod 

6'"o (-4.7 oleo to -5.2 olw) similar to Dolomite 1. and others are per- 

vasively altered by dolomites vith moderate 6'"o (-7 0100 to -10 oloa). 

Carbnn lrotop values do not vary ?mm thoee of the original limestone 

(-0.5 OlOO to -1.5 0100). 

The dolomites are atoichimtric ($0 mole % CeCO,) with o d,.,, peak 

spacing of about 2.888 m (Appendix C). 'The trace elements k, Mn, and 

Ne are present in minor aunts (Appendix 6). Imn locally reaches 1000 

to 4000 ppm in the fermen dolomites. Moderate 70 to 200 ppm mncentra- 

tions of rtmntim are reportea by Haywick 11984) far mttle dolostones. 

Evidencs of ~iminq - crystallization of Doimite 11 spans early 

diageneais and the initial phases of pressure solution. Cathadolmi- 

nascence exhibits this history as zoned purple a crystals overprinted 

by later pink a dolomite (Pl. 5.lh). The uida-ranging isotopic values 

also rsflect changing fluid chemistry. 

Dlmite Ii replaces microspar and hems of insoluble material, an4 

locally surrounds microbreccias of pseudospar (PI. 5.361. These 

features indicate that the dolmitiration port-dates early carpaction

and Iimencslone diegenesis. Calcite veinlets which cut doloatane mttiro 

(Pl. 5.2~; 5.W and stylolites which tr.ncate brecciated rhds 

IP1. 5.3e). together denonstrate that sme dolomites pre-dale praasure 

rolution. PervasiVE dolostones also pee-date rtylolites (Hawick, 

1984). The meny euhedrel crystals vhich *cur along styiolltaa in 

limestones, however, imply that dolomite gmuth continued during 

pressure solution (el. 5.101. 1% crlstsis cnnanly displace stylo- 

cmlates of insoluble naterial (Pi. 5.3e) and .lthcrs are surrounded by 

bifurcating stylolites (PI. 5.3a.c). 

Internretation - Gmposite crystals of Dolomite I1 fomd over e 

long period fm shallow burial to pressure solution at depths greater 

then 300 m (Neugebauer, 19731. Purple a dolomites in burmu nxrtties 

1.46 

and pervasive dolostones ware probably cant-raw with Wlwite I, but 

mbt crygteis nucleated in the shallow subsurface after the formation or 

microspar and rmnpaetion seams. Typical t1:cbid doimites inconpletely 

replaced micmspar, a characteristic of early dolomitiration frm fluids 

saturated with respact to oaloite (SIbley, 1982). Briqhtly zoned, 

fermn dolcmites probably crystallized in areas of slow-mving reduced 

waters (sf. lrank d el., 1982; Omver and Read, 19831. 

Pink a dolmite dwelopmd euhedrsi rims during deeper burial and 

pressure solution. The early purple a cores vhich lomd in equi- 

lihrhrium with calciwrich fluias becam unstable and were prtially 

replaend. 

Although Lldtiaation occurred &ring pressure mlution many 

crystal nmcleii, SON nottles and mart pervasive dolostones had already

iumed. The cmonly dulomitized ssamr of insoluble nwlerlsl largely 

uziginated during early smpapsction (shin" et al., 1981). Dolomites in 

burrows and many disssnrmated crystals nucleated seperately frm any 

aeme or atylolites. These relctionshlps svppvrt arguments of Pratl 

(1982) and Haywick (1984) against pressure aolutlon us the major 

mechanism for Joimitisatmn (Wenlens, 1979) in these rocks. 'ma 

abundance of detrital feldspars in dolostone nlottles, highiighted in CL 

1,11 

(P1. S.lb,c,e), suggests, harever, that solution and displacmnt during 

dolomiti~ation concentrated these grains. 

5.5 Dldte Tppe 111 - V w fine to mdium cry~tillline, 01- crystals 

rith bright, zooed a 

Petroqra~by and Distribution - blmite 111 conatltutes only a minor 

portim of dolostones in the srea, but it m rk a sipnifioant change 

from turbid, replecmsnt crystals to beightly luminescent zoned cements 

in s~ondarp micropores and fractures. blmitite I11 dlstinctivsiy farm 

isopachou~ s-nta in fomer pdrer (PI. 5.lc) and clear syntaxiai rims 

on turbid Dlmite I1 crystals (Pla. 5.ls.d; 5.4a.b). The dolomite 

pervades precursor dolostonas: mck-matrix breccias, Aquathuna doios- 

tones and dolostone beds within the linestones. The dolomite is 

pminsnt in mck-matrix breccia. where it ovemrous fine 10 )M crystals 

in $me fragments; €oms thick rim on 100 to 500 )M rhms which 

replace matrix (Pls. 5.ld; 5.W; and cements fractures and rolvtian 

pores. In fine crystalline doloatones of the Cetoche Pornation 50 to 

200 w rh& and isopashous layers cement solution pores (PI. 5.le);

a. C-site "Cm' crystals with cloudy sores (Type 11) end clear 

rlns 111) replaoe rock-natrix breccia. ~ine crystals overprint 

fravnts whereas mdiunrsized ones =cur in the matrix. Smple Em. 

WH 66, 132 m, in the Mike M e rock-matrix brsccia (locetian, Fig. 

1.4). 1 m scale. 

b. A cdinatlon of CCCR ~r~stalh and cleat hlwaita I11 cementa 

replace fomer Dattlen of coarse calcite in Catoehe dolostone beds. 

Plate 5.lf is a similar ~ l e Upper . (atocha Formtion, DDH 1254, 18 

m b.w.m. 1 m =scale. 

c. clear crystals with dnute fluid inclusions and halite inclusions 

(?I (arrow) characterize Dolmite 111. Alternatively, the arm, points 

ta a negative crystal t n phase fluid-vapor inclusion. This inclusion , 

lnarphology suggests farnation st a significant burial depth (J. 

Reynolds, Pluid Inc. Caurse Notes). 75 rn scale.

aplacs calcite-filled buzroys (pi. 5.4bi: and form intcrcryst.lllise 

cemnts (PI. 5.le). In microcrystaliine dololaminiter only mlnu~c b to 

20 m rhd9 occur in intercrystalline pores (PI. S.la). 

I?," 

hcurrences of Dlmite 111 in limestonos is scattered. 1t appnrs 

pmninently in ueinists where medium 100 to 0 0 )un crystais c-nly 

rcplase equant calcite o m t s (Pls. 5.2~; 5.3a). lsopa~hovs cemnir or 

medium-sized crystals also fill solution pores around dolostone mttles 

(Pl. 5.34 and along vertical sutures of styloliteb. Within dolortone 

awttles very fine crystalline dolmite f om thin intercrystalline 

cements and overgrowths of Oolmite I1 crystals (Pl. 5.lb,e). 

CaLhodolumineseence - Dolomite 111 is distinctively zoned with 1 to 

20 ym vide bends of alternating yellas-orangs, red and pink Ll (PI. 

6.ld.e). A stratigraphy of 5 to 12 roncr in bloeky pore cents 

correlates more than 5 bn. m brlght yellow zones fom the ubiquitous 

clear crystal rha. The diatlnetion between pink CT Dolomite IT and 

Dohnite 111 is arbitrary. Plate 5.le clearly illustrates that the late 

pink a phase of Dlmite I1 fdllovs extensive dissolution of ths cerb- 

nates and it bms the first isopachour cements. Zoned Dlmite I11 

continues the grMth of these mentr. 

Gwchmiatr~ - Dlmite III-rich &lostones frm r&-mtrlx 

breccia* (this study) and pervasive dolostone beds (Hapick, 1984) have 

mderate 6"o values ktvsen -6.5 and -8.0 o/aa PO6 (PI=. 5.2, P.ppondix 

A). 6'"C values are noml, -0.5 to -2.0 o/a, ma, and depleted to -1.0 

doo m.

he rtoisnimerric (51 wle % CeCO.1 doimites hat..! n d,,,. rpaclng 

niwnd 2.888 m Inppendix c). The dolanites ale grnerelly xodium-rich 

and vary in iron and manganese canposition (Eppmdix I). Anomalous. 

1000 Lo 30,000 PP", edium frm rnicropmbc point ensiyscs is reiald lo 

I ,i 1 

common halite crystal inclusion% (PI. 5.1~). Stlontilvo 18 depleted, 50 

to 90 pm,

Figure 5.3 variation in Imn and Manganese Abundanees 

is Zoned Dolmite I11 

nicmprobe travsrses of iron and mwnese abundanoe in Eonea 

cryst01 layers of Dolmlte 111. Elevated no values (900 to 1700 ppm) 

with brightly luminescent (whits) crystal layera. noderetely lumines- 

cent crystal layers (stippled) have Nn abundances of 400 ppn. mis 

mned Doldte 111 crystal occludes a pore within a partially dolo- 

mitizd limestone in the vpper Catache Formtion (DOH 1254, 19 rn 

b.w.m.1.

Fe AND Mn IN ZONED DOLOMITE Ill

m (Neugebauar, 19731. Possible negativ6'orystal inclu.~iano support a 

deep burial origin. 

154 

Internretation - The transition from weekly isminescent klmite 11 

to zoned Dolonite 111 is chivacterist~c of cartanate cementation a1 

increasing burial depths (?rank et al., 1982; ~ro~cr and Read, 1903). 

Hallte inclustona w ly chat the dolmitms prccipltated I- hypersaline 

fomtlonal brines. The lwninescant crystal layers pmbably incor- 

stated Mn under reducing conditions (cf. Prank st al.. 1982). Their 

association with stylolitss Inplies that they precipitated at dsptha 

greater than 300 m. 

DOlmItizing brines parsed through pemeable, precursor dolostones, 

but also along fractures and rtylolites in linsstenea. The vnstable 

early dolomites and sane calcites partially dissolved; an event which 

rrea Iollared by the pracipitati~ of the pink CL phase of Dolanits 11 

and Dolomite I11 as crystal overgrwths and iaopeshous c-nts. 

Important gemtrio aspects of this dolmitiaatian are considered in 

Chapter 8. 

5.6 mlmite Type IY - Pine to maim srystalllns, replac-t dalcaite 

with red a 

Petrwrmhy and Discributlon - Rare fine to medium crystalline 

mosaics of xenotopic dolomites (Iv) occur instratigraphic grey dolo- 

stones within the wpsmst Cetoohe Formation and discordant balies

alonr faults in lower parts of the Formtion (Pi. 5.52). Coarse 

dolortone beds in the catoche mrmation locally preaerva patches or 

mottles of these dolomitee (PI. 5.ig). Rbundsnt Pray dolostones pm- 

date Dolomite v because they are cross-cut by sulphidc-cmsnted veins 

end solution p~es. other than the fw remnant p>tcher of IMlmitc 1V 

these gray dolostoner are recrystallized to Dolomite V. Geanntric 

relationships between these dolostones, sulphides and coarse dolostone 

beds are examined in Chapters 11 end 13. 

Cathodoluminessence - Cathodoluwinescence demonstrates that the 

medium to coax%-sized, 300 to 700 irn, crystals are poikilotoplo ones 

which include and replace earlier rhhs of Dolomites :I and I11 (PI. 

5.11). The crystds luminesce bright red and the replaced cbmbs have 

,,.. 

dull red core8 and the orange-red signature of rim of Dolomite I11 (PI. 

5.lf.9). 

Geochemistry - Oxygen isotopes of Dolomite IV samples have a 

maderate 6'*0 of -6.88 to -8230 o/m PDB (Wpendix A). 6'"C cantent 

varier from -0.9 to -1.40 0100 PUB. This isotopic conposition la 

tihilar or slightly depleted relative to Dolomite I11 and enriched 

relative to wt samples of Dolmice V (Fig. 5.4). 

Stoichimtric dolmites with 50 to 51 mole a Cam, pmducs a/d,,,. 

peak at 2.88 to 2.89 MI. Trace elnent content is variab1e:Fe" at (100 

to 2500 ppm vith a 1300 p p mean; Mn" at (100 to 2500 ppn vith a 600 

p+m mean; and erratic aunts of sodium. Pe"/Mn" ratlo. as la as a 

to 0.5 my partially account for the bright luminescence. Organic or

plate 3.5 gp~genetic Dolmltes IV and V 

.. Henotopic crymteis of Dolomite I V form the caarsa natrh of this 

dismrdant dolostme. Middle Cstoche Formation, Dm 1134. 50 la. Pol- 

acizd light. l ann rsale. 

b. ~wpetal dolomites fill the base and saddle dolmite smnb the 

#upper portion of fractures which cut a precursor dolostone. Crystal 

textures of the inset are illustrated bolw in PI. 5.'5d. Undergmund 

sample frm the west L Zone tiacstion, Fig. 1.4). 1 an rsale. 

c. Pseudobreccia. Patches of gray dolmites ompise (A) gray matrix 

dolostone, (B) burrows and (C) coarse crystals rith black intercrystal- 

line material. White saddle dolomite ooolnl as replacant crystals (E) 

amvod grav dolomites and as a cmnt ID) around pores (p). Frm the G 

zone open pit (Location, Fig. 1.4). 1 m scale. 

d. Ewant rhds (A) of Dolmits V with black intercrystelline 

material replace geopet.1 sediments and are overlain by megarrgwline 

cements (8) of Saddle Dolwite A ritn planar crystal buoundKias. 1 m. 

e. Pseud@brccie. Turbid, xenotopic roplac-t doloftes (a) €om 

gray patches. Replitoement saddle dolmites (bl adjacent to patches 

grade outwards into large cement cqstals (c) uith.planer hndaries. 

Polarized light. Sanple a- as 5.5. 1 w soale.

E. 

Xenotopic, replacement saddle dalamitcr (a) locally praseme blown 

t~ gray residue8 of pre~rsor carbnates. Cement crystals (bl, by 

,';,I 

c-rioon ere white and phr-edged. Polarized light. Same bamplc as 

5.5E. 1 m sca1s.

L'igure 5.4 I9otope and Nvid Incluaron Data for Epigenetic Wlmititen 

and Ul1cite. 

plot of 8'"o YS. 6"c values for epigenatic dolmitas (Iv. V, 

v1) and late calcites [data in Appendix A and mron, 1982).. Dolomite V 

is aeparatcd into 5 gmups: (11 overall field of Saddle Dolomite A, (2) 

ore-stage Saddle mlmite A, (3) late stage Saddls Wlmite I, (4) 

saddle Wlolnite A outlying ore m s ma IS) coarse s- doloatonas 

adjacent to unaltered linestonss. Wlmite VI is represented by Saddle 

Dolamlta B uhish overgrows Sadale Wlmite A. Lste calcite acludes 

former cavities lined by the saddle dolanites. 'Phe plot shma a 

depletion in 6'-0 values of ore stage dolmites relative to ather om. 

SBZlal Panplse of cavity OPDBD~S E m are-stage to late stage Saddle 

Dolomite A to Saddle mlmits B dmnatratea a pmgreasive depletion of 

6'"C and snrichnt ox 6'-0 (open ciroles and arms). Occluding late 

calcites indicate a depletion oE 6'% by fractionation relative to 

dolmite and further 8°C depletion. The distinct fields for Saddle 

mlmiles I and B sna late oalcite suggest that they precipitatsd during 

thrae separate events from fluids with different chetaisy. 

Pluid inclusion data for Saddle Wlonite A and late calcitea 

supports this conclucioo. late calcites have distinctly lwr malting 

tempersturea (-36'Cl and h-enization twerat- (50-C) relative to 

Saddle W hite P. (1. = -2S°C; h = 112'C).

FLUID INCLUSION TEMPERATURES 

SADDLE DOLOMITE A 

T.-50.c Tm -24% 

Th mod.-110~~ 

LATE CALCITE n-M 

Th mode - 55% 

rio'c 

11-17 

. 

I

161 

ether trace natter in bran reridue ptch.hes could also generate luminee- 

eence. 

-- Evidenoe of - Cathadolwninessense clearly =harm that Dlu- 

mite IV overprints rhombs of Wlomite I1 and I11 and is crosscut by 

veilllets cemented by Doimito v with its distinctive duil red CL [PI. 

5.19). Sulphide-cmnted veins indicst~ the pre-om origin of these 

dolmites. 

Interpretation - Dolanita Iv prvasively replaced medium crystal- 

line rhomba of earlier doloniiter. Its position bstveen Doimite 111 md 

vein cmnta of Dolmite V implies that the doiolnitiration occurred 

during deep burial. The xenotopic crystal textures suggest hydrothemi 

origins icf. Gregg and Sibley, 1984). The cwstals probably lncor- 

parated the significant aunts of Pe and Mn under reduciw conditions. 

oxysen end carbon isotopic values similar to rhe precursor carbonates 

suggest that the fluids reached equillbrim with the host during the 

replacement dolondtiration.

Petroqraphx and Distribution - Iwrtant ma V dalunitcr vlth 

variable textures caoprise mrt of the coarse dolostone cmplexcli in ~hc 

upper catoche mrmation and include the white, saddle dalmite cants 

which immediately follow sulphide precipitates. These dolmites 

cwrire most of the dolostones in and around nine workings. The 

dolomites selectively replace eormer ploidal grainstones and wacke- 

stones and fill cross- cutting veins and megapares. The doloatone 

lithologie~ vary E m uniform gray, d i m to coarse dolastones to 

mottled gray and white pceudobreccias with megacrystalline saddle 

dolomite (Pi. 5.5; Chapter 13). Crystals can be categorized into throe 

types: (1) fine to mdiun-sized xsnotopic replacement crystals with 

plane extinction; (2) medium to cotrse-sized, xenotoplc to idlotopic, 

replsc~aent orystsis of want saddle dolmite; and 13) prismatic and 

blosky, coarse to megacrystalline saddle dolmitea which cement meso- 

pares and aegapores. Saddle or "bamyme" dolomites are resognired by 

their sweeping undulatory extinction, cleavage and curved, drfomd 

crystal structure (Folk and Asserto, 1974; Radke and lathis, 1980). 

Saddle dolmites of generations v and VI are referred to as Saddle 

mlmites A and B respestively. 

(1) Fine to medim-sired, 20 to 200 p,. replacement crystals with 

plane extinction are largely mnotopis and want. The turbid crystals 

contain residues and nunremus mic-tre-sired fluid inclusions [PI. 

5.5e). lmrphisn has enlarged earlier generations of crystals. The

1r.1 

;.aplil~-nt crystals v~thin mttien or beds of gray dolostone grade into 

nsdiu. to coarse gray crystals of sddls doimite vith mild undulatory 

extinction (PI. 5.5e). 

(2) Medim to coarse-sized, 100 to 500 m, replac-nt crystals ut 

saddle dolmmita with undulatory extinction are nenatopic and vary €ram 

grey to white it, colour. The equant replacement Oryskvls include a 

variety of crystal textures. Gray irenotopic crystals pertinily repiaca 

gray mottle6 (Pls. 5.5c.e; 5.7 a,bl. Medim-aired, white crystals with 

irregular intergmwn boundaries are transitional between gray mttler 

and void-filling saddle dolomite (PI. 5.5c.e.f). Bmwn residues are 

conuwnly preserved in these crystals (Pi. 5.51). These vhite replace- 

ment saddle dolomites are o w n in pseudobrecsias with more than one- 

third vhite dolostone (PI. 5.5~). 

Euhedral equant rhds of light gray dohita replase geopetal 

redimencs (Pl. 5.5b.d) and the tops of gray dolostone mttles in 

pseudobreccia (PI. 5.54. The oryatels displace and concentrate black 

Insoluble material between the euhedral rhombs. This material gives the 

dolostone a blask oolm. 

neplaccnent saddle dolomites for. Ewrse "aparry" dolostoner in 

areas of transition between pssudobreccia and limestone (Fig. 1.51. Tlle 

crystals are maim to coarse, ewant, llliotopic rhonbs with a llght 

gray solour. characteristically they overprint burmumottled and 

stylolitis fabrics (PI. 5.7a,b). Crystals connaly nucleate around 

primary peloihl or inclusion-rich cores and are surrounded by unce- 

mnted intercrystalline pores (Pi. 5.7a.s). Intergrown renotopic 

dolanites ocmr looally In gray mttles (PI. 5.7~).

a. 

"late 5.6 Fluid Inclusions in Saddle Dolomite and Ute Calcite 

~luid inclusions in saddle dolomites very fro. iparsa occurrence in 

late saddle Oolomite u in the lower left to great abundance in saddle 

blmite B in the upper right. Unaswmna smle from the X zons 

(Location, Fig. 1.4). 100 !m scale. 

b. Fluid inclusions in Saddle mlemite II rang* in size f m 1 to 10 

pm. Bane sqle as 5.6a. 25 pm scale. 

c. nillimetra-sized fluid inclusions in Me calcite irary in shape 

fcm ws.t to tabular to necked toms. Unaerrlmuna sqle fm. the X 

zone (mation, Fig. 1.4). 75 pm scale.

Plate 5.7 ~olomltes Y and VII i n mcrra Spariy Dolostones 

a. coarse sparry dulostone. Equant, hypidiotopic saddle dolomites (VJ 

replace and nucleate on preaxaor peloidh (arm*). Smle f m the L 

Zone area. 1 m scale. 

h. coarse *parry &lortonss replace the mtiix rwrovnding early dolo- 

=Lone mttles, which they also overprint. Sample fm' the L lane area. 

1 on scale. 

C. One to tw millhetre-sired pores characterize cmse sparry dolo- 

stonones. Lack of s pore-filling gemtry of surrounding rtraabio crystals 

suggests that pores fomd during late dissolution of unreplaced Ilns- 

.Lone patches (Murray, 1960). Polarized light. Sample frm the L Zone, 

Wn 626, 155 m. 1 m scale. 

d. Late Mlmite VII uniformly overprints bur- fabrics (armr). 

solution pores along atylolites suggest that dissolution post-dated 

uplift. Slunple Im north of tHe L Zone, DOH 961, 165 m. 1 m scale. 

e. sinilar solution pores along stylolites ocw in finely crystallins 

dolmitae in the Table Head Gmup. Many crystals are nucleated on dusky 

peloidal Eores (arrow). Smple f m the L Zone ares. 1 m sde. 

f Dolaiter [VII) from PI. S.7d are finely crystalline, eymigran- 

ular, euhsdral end nucleated on primary peloids (am). 1 m scale.

la) White, tlensiucant void-filling saddle dolmite. contain 

abundant micraoletre-sized fluid inclusions, miwar mai&!es and sweeping 

undulatory extinction (Pls. 5.5; 5.6'~). Open space-filling dolunites 

distinctively have straight edges IP1. 5.5e.f). Crystals at the edges 

168 

of pores penetrate and replace ion to 1000 m into precursor do~arni~er 

(PI. 5.5e.f). Crystals coarsen toward central pares from 100 to 500 pm 

long oryatal8 along walls to 2 to 4 m long primtic fom to 4 to 10 

m diameter blow cryetals in centres. A 100 to 300 pm vide nrter edga 

of thsse crystals has minor fluid inclusions \PI. 5.6.). 

Cathodolmine(lcence - Wlmite V crystal types uniformly lumineaca 

dull red (PI. 5.lg,h). ~epiacernsnt crystals tend to lmines~e darksr 

red than tk d dla dolmite cements. Lmel ferroan dolmitea luminesce 

dark red. Faint zoning in the saddle dolomite cment, seen in plans 

light and hand specimen, appears as up to 12 zones under ct. 

Coarse replacement EIYstals eraas evidence of earlier dalmite CL 

where primary structures end fractures imply earlier dolmitiaetion. 

Medium to coacse, 200 to iOW m, crystals m nly preserve evidence of 

nemmrphic origln as dusky residues of peloids and burrow walls, but 

prior a phases are lost (Pls. 5.5f; 5.7e). In fine crystals, lens than 

200 m in diameter, bright orange CL rims of earlier zoned Mlarnite 111 

rmin under a mesk of duLl red lminescence (similar to PI. 5.lf). 

Gwohemistq - Forty-five oxygen isotope swles (this study and 

Comn, 1982) of Dolomite V define a bmad field fmn nomi to Pepleted 

values of -7 to -12 o/a, B'd PUB (Pig. 5.4, append% 11. Carbon

16'1 

imtopea values, which range fma 0 to -2.0 olm 8°C m.9. do mot dltfrr 

significantly Iron pmcurrar limstanea and dolostonas. These rssuite 

correspond to data For saddle dolmitea thmughout northwest Newfound- 

land (Hayvick, 1984). 

Detailed swle traverses across saddle dolbxru;iir cement aeqaences 

of the P, K, L end Tore zones mpmtuce slgnif~cant psroilei variations 

lo both 6'"o and 6'.*C (Fig. 5.1). Observstions are sumrired as 

follows: (1) Saddls dolmite cwent In .reins is depleted 0.5 to 1.0 per 

mil 6"o relative to replacmnt crystals. (2) Dolonitcs precipitated 

directly after sphalerite crystallization Porn n tight gmup between -9 

to -11 0100 6'"o and -1 to -1.5 olm 6'"C. (3) Pmgresrively younger 

dolmitea are depleted in 6"'c 0.22 to 0.53 ojm and enriched in 6"'O 

0.10 to 0.23 olm PDB relative to initial cemnts. (4) Saddle doimites 

and coarse s pry dolostones peripheral to ore zones are either de- 

pleted, -10.5 to -12 oloo, or enriched, -6.5 to -9 oloo. in 6"'O 

relative to ore zone dolomites. 

Thebe dolomites are stoichimetric (50 role \ Cam,) with ad.,,. 

peak spacing around 2.885 m (Appendix C). Saddle Dlmites Fron 

elsewhere on the Northern Peninsula tend to be enriohed in Cam, 

(~aywisk, 1984). Moat dolomites around the ore zones are slightly 

fermn, 900 to 3500 pp. (Appendiu 8). only the outer edges of ore aone 

orystels are Fermn. Perman Dlmites occur locally outside the ore 

zones. ~e"/Hn" ratios of 14:l ere k ed upon nn contents of 250 to 

300 ppm. stmntim ooncentrationo of 15 to 135 p ~ with n a mean of 61 

ppm are depleted relative to Dolomite I1 (Haywick, 1984).

-- 

Fluid Inclusions - Typical, low relief Fluid inclubions vary fmm 

one to several micmEtrss in ni~e. Pink fluids contain smli vapor 

bubbles, equal to 1 to 2% of the total voltme (PI. 5.6b). Sixty-three 

measured inclusions heat to d a l h-eniration temperatures of 112'C 

with a range frm 42O to 133T [Pig. 5.4). Anmalous inclusions 

hmgeniza st 48', 65' and 164'C. Inclusions f m eilrliost dolmitea 

have the highest Dean homogenization temperatures of 130°C. eight of 

the studiad inclusions are large enough to observe freezing and melting 

of fluids. Typicel inclusiona ere CaC1,-bsaring and thus havs initial 

1711 

m1tir.g. or euteotio, temperatures around -5O0C. salinities of 23 to 25 

Bgliivalent wight % NaCl (final 8mltir.g temperatures a€ -24 to -28.C) 

are similar to those of sphalcrite inclusions. I few lvver salinity 

inclusions of 16 to 18 equivalent weight t NaCl havs a~lously high 

and low homogenization t-ratures of 48- and 130DC. 

-- Evidence of Tinin4 - Saddle Wlmite A which cementa veins and 

nscropres follows sphalsrite precipitation and precedes acclusion of 

those pores by Saddle Dolomite B and late calcite (Pl. 5.lh). Saddls 

dolmite vein. cut earlier dolostoner end sphalsrites. The similar CL 

end geochemical properties of and gradational relationships between 1111 

dolomite texture- imply that repleeenrent and cement dolmites are the 

siuae generation. Therefore Saddle Wlmite I has been gmuped with the 

gwchemically similar replacDlnent dolmites under Rme V. Stylolites 

along gray dolostone mttles inply that the dolmitea crystallized 

dvring burial (PI. 5.5b.c).

' 

Tnterrrretatian - Lblomite V is a characteristic hydmthermal and 

deep burial dolomite. Fluid inclusions vith elevated hypersaiirbities 

and h-erlization tmpraturer indicate their origin frm hydmthomai 

subsurface brines. Saddle dolomites and xenotopic textures ere chorac- 

terlstis oE hydmtheml dolan/tes (Redke and Mathin. 1980; Grcqg and 

Sibley, 19841. Their association vith sphalsrite supports this con- 

clusion. Depleted 6'"O valuer of saddle dolomites associated vith 

suiphides pmbably record hydmtheml effects. 

Replacement by both nomland saddle doimites is prvasive and 

extensive. Thin observation 1s slgnifisant because m t seddis dolo- 

mites are reported as pore-filling cemnts (Radke and Hathis, 1980). 

Sbilar pervasivs dolostones with vnifom luminescence are, however, 

r~ognized elsewhere as oharacteristic of dmep bburlal dolomitization 

(Redke. 1918; Hormv et al., 1986; Lee and Friedmm, 1981; Aulstead and 

Spsncer, 1987; Rman and Medary, 1987). 

Petroqrwhy and Distribution - Poikilotopic, inclusion-rich saddle 

doicnites cement mgepores after presipltatlon of Saddle Doiafite A 

111 

(Plr. 5.19; 5.6a). Although they constitute only a minor portion of the 

total saddle dolomite in the area, these crystals signlfy a distinct 

pr~ipitation event. The translucent white to pink doimltes vary from 

thin -thick overgmths to 15 n-dimter mgacrystals. Saddle 

Dolafite B syntaxially ovuqms Saddle Dalmite A, but it also cements 

fractures and breocias of apheierite and saddie mlomite A (PI. 5.111).

Cathodolminessence - Oolmita VI is distinguished fmw preceding 

crystals by its bright red CL in which coincident crystal and cL zono 

boundaries are abrupt (Pl. 5.lh). Catliodolmlnescenca hlghllghtr 

cmsntr in IM-thin frectursr which cross-cut Saddle Dolmite A and 

sphalerites, and thin cements qf solution rims around sulphides. Relic 

intem~ystalline pores are also cemented (Pl. 5.191. In places. these 

172 

fine cmnts give the swoalte medim cryrtalllnc dolostones a brighter 

red luninescence than the coarse saddle dolomite. of ooim~re v. 

Geochemirtq - Saddle Dolomite 8 is enriched 1 to 3 per nil in 6'"O 

and depleted 1 to 1.5 per mil In 6'"C relative to Saddle Dolmite A. 

Five sanples of saddle Oolmite 8 from centres of thrse ore zones define 

e field between -7.5 to -8.84 0100 PDB 6'*0 and -2.24 to -2.81 0100 POB 

6°C (Fig. 5.4. ApPendlY A). The isotopic trend of saddle Oolomite A 

orystallination thus extends to Saddle Dolmite B crystals. Ilro s.wples 

reported by mmn (19821 from the outsurts of the L Zone continve the 

trend even further to -6.4 to -7.0 olm PDB 6"O and -4.1 01- 6'"C. 

Late megacrystalline calcites whish occlude megapares have depleted 

isotops values of both 6'"o (-10.19 to -11.60 oloo m8) end 6'"C (-3.35 

to -4.21 olm PDB) (Pig. 5.4, Appendix A). 

These dolomites are stoicbtric (50 mle % Cam,), similar to 

Saddle Dolmite A, with spacing of the d,. pea* around i.885 nm 

(Appendix C). Saddle Dolmits 8 is slightly mre ferman than Saddle 

Dolornits A, 5000 ppn canpared to 3500 pp, and the crystals respond to 

potassim ferricyanide solution with a light blue stain (Appendix 8). 

The manganese content is twice that d Saddle Dolomite A, 600 ppl

cwarsd to 250 ppm. FelMn ratios or 5 to 6 mey occwilt for tltc red 

lwinesoence. 

I/, 

-- 

Flvid Inclusian~ - 'No fluid inoiusions h-cnized at ~vmqcratures 

of 101' and llO'C. No freezing mussurements could bc conducted. ln 

general, the rock is tw gray and inclusions are t m small and cioscly 

spaced to be clearly visible fP1. 5.6a). Sellnities are above 24 

wivalent wight \ NaCl (5, = -36'. Pig. 5.4). -arable to hyper- 

saline inclusions in Saddle Dolamite & and late calciles. 

Lame fluid inclusions preserved in subsequent late calcites 

illaicate progressive increase in salinity and decrease in Iluid tempera- 

tures during pore filling relative to the saddle dolomites. he 

millimetre-sleed fluid inclusions are hypersaline with low final melting 

temperatures of -34O to -38-C (PI. 5.6"; Fig. 5.4). The inclusions also 

h-eniae at relatively -1 modal temperatures of 61°C. 

-- Evidence of - Doldte VI (saddle Dolamite 8) mollovs Saddle 

Dolaaite A sa a cement in megapores and fractures. nqacryrtalline late 

calcite locally occludes weporea. Euhedral crystal faces in open 

pores are w ergm by a variety of crystals of calcite, sulphates, 

mamasite, whalerite and galena, and ooetings of pymbitmen end 

h-tite. 

Intermetation - Rfter brecciation and fracturing a€ previous 

sulphide and Dolomite V cements Saddle Dolomite B precipitated as a 

poikilotopic cement fraa a hypemaline fluid. The crystals were

enriched in 6'"O and depleted in 6'"C relative to Snddle Uolmite A in 

response t a cooler, reduced fluids end decreased fluid int~ractlon with 

114 

the host rocks. The depleted 6 ' " ~ values might be inteipretd as lntro- 

dustion of organic hydrocarbons in the fluid and/or sn incrsaring fluid 

vs. rock signature with decrsasing well rmk interaction. here 

changes also led to increased Un end Fe concentration end precipitation 

of calcites at lw tenperatures. 

5.9 DDlcaite rn vr1 - FinB to OCaraB ~ ~ l l l 40-C. n e rith re (Z 

disrributsd along late famlts 

Petmraphy and Distribution - Porous, pervasive dolastones replace 

Catoche end Table Point limestonas aloq late faults vhiah displace 

bodies of earlier dolomites. Pine to cwrsa-sired, equigranular end 

equant crystals replce the lhstones end overprint primary mttiing 

and styloiites (PI. 5.7b,d). The idiotopic to slightly intergrown 

Uystals are surmvnded by abundant.porea between crystals, aloy 

rtylolitss and in fomr calcite-filled fenestrae (PI. 5.lo.d.e.f). 

Individual rhds camnly nucleate emund plaids (PI. 5.lf). Ooloo- 

tones which replace mssive to fenestrei mudstones of the Table mint 

Fomtion ore distinctively fine crystalline and buff-coloured cwared 

to fine tn coarse dolostoner which replace Cstoshe limosatones (PI. 

5.ls.e.f). Nucleation around fine grains in mudstonas an opposed to 

coarse peloids prebably accounts for this difference. solution pores in 

the Table mint mmtion are pattially cmsnted by marse saddle 

dolmite and late iminescont yellow oaisite.

Cathodolminercence - Crystals lmlnasce a uniiam bright. red with 

no sonation. Residue-rich, irregular brown patches and paloid mtcicii 

contribute significantly to this luminescence. 

I75 

Omhemistry - 0x0" (1982) reported isotope analyses for a variety 

of these dolonrite types. mimites in the Table mint Formation conlaan 

relatively ""depleted 6'"o end 6°C. -6.7 to -7.6 01- PDS 6'"o and -- 

0.6 to -0.7 o/w PUB 6°C. One Catocha swle falls in the same 

field, -7.3 o/w PDB 6'*0 end -1.1 alw PUB 6'"C (Pig. 5.5). East of 

the minc area other Cstoshe doloatones of possible Wlmite VIl origin 

havs widely dlvsrgent depleted ."a snriehed 6'"O, e.g. -13.7 olw PDB 

6'"O and -4.9 0100 mS 6'"O (Comn, 1982). 

Stoichometric (50 mole % Ca) dolomites are iron-pwr,

Figure 5.5 Isotopic Ueta for Late Pault-Related Dolomites (VII) 

Plot or 8'"a vs. 6"c values for Dolmite VII (coron, 1982). 

~sotopio values for Dolmite VII plot in three flmlds. Calculated 

uaterrae* ratios Crm variable water cmmsitiona (dashed lines) 

suggest that isotopic differences reflect the role of meteoric water in 

dalmitieetion.

suggests that the dolamites crystallized at shello" depth; after llplifl 

and the csssation of pressure solution (PI. 5:le). 

Interpretation - Late stage dolomitization replaced llmstones 

along nart faults. Fluid inclusipnr indicate that dolomitizing tluidr 

were probably hypersaline, but variable isotopic values imply e variety 

of fluid Sources and emposltions. Crystals nucleated m fine mud and 

peloid grains. Limestone replacement left between crystals a combine- 

tion of displaced insoluble material, intercrystalline ne-res and 

selective solution pons along atylolites end tenertrae. Late solution 

probably r-ved dolomites or lhestone patches to lorn the intercry%-- 

talline mesopores (PI. 5.7~). Selective solution along styialites 

suggests that dolmitiratlon accwred after uplift. 

1'111 

The seven dolomite types are grouped under four diagenetio enviran- 

mnts uhieh are loosely t emd (1) syngenetis, (2) diagenetic, (3) epi- 

gsnstic and (4) late fault-related settings (Pig. 5.6; also refer to 

Fig. 1.6). 

or primary dolomites (Freeman, 1972) ere identifisd ae 

orystals which fomed f m solutions generated at ths surface. Dolordte 

I end the nucleii of Dolmite TI ere inelud~d in this group. Dolostone 

fr-nts of I and I1 in intrafomational conglomerates one karst 

breccia8 indieata their origin at or near the surface. The dolonitizad 

matrix of subsurface karst breocias implies that ayngenetic dolomitiza-

Piguce 5.6 Paragenetic Sequence 

Chart of paragenetic crystal steges ond their relationship to 

geologic events and the premed depth of burial and gwlogisal the 

scale.

Lion penetrated tens of metres below the surface. 

dolomites speoify crystals which fomd during burial 

and the change from near sudace to subsurface pare flulds. This 

definition differs f m others rnich encompass doiamitization after 

lithification or all early dolcnit?~ (chilinger at al., 1919). 

1R1 

Diagenetic dolo~nitiPatlon formed ubiquitous and stratigraphic dolaniten 

as carbonates reacted to c-ctian, pressure solution and fluid 

migration thmugh early dolostone beds. Typioal oompoaitc crystals of 

Dolmits I1 experienced partial solution, replacement and overgmmth 

Wing progressive burial to depths of pressure solution. Zoned 

precipitates of Dolmite 111 mked the final phase of dlagenetic 

crystallization from deep fomtional fluids. 

Bplg.naLic dolomites, types Iv. v and VI, crystallized In the deep 

subsurfa~e where they were locallzed along strusrures (nnparahle to the 

definition of Fricdman and Sanders, 1967). although these dolaniter 

occurred along faults and fractures they also extensively replaoed 

stratigraphic units such es the upper Cetoche Fornation. Tha dolaniti- 

zatien was distinctively hydmtheml. 

-- 

late faolt-related aolrmitss, type VII, were also structurally 

controlled. These dolanites, however, distincLiveiy lacksd abundant 

saddle dolomites and xenotopio textures that were typical of the 

hydmthenoal epigenetic dolomitss. Thsy crystallized along faults that 

fomd or reactivated during regional uplift. 'The dolmitization 

occurred hiring and after uplift when svbrurface brines and mteorlc 

waters migrated along the faults. 

Figure 5.6 graphically displays the relationship between these

li17 

diagenetic stages and other events (see also rig. 1.6). Mmt ayngcnetic 

Soiaites crystallized prior to karstificetion. oolmite I1 'rplacrd 

diagenetis ceicitea (nitrite. microspar and pseudospar) at this time and 

during burial. Calcits-cemented velniets, however. cut marly mttics 

of Dolmite I1 and were truncated, in turn, by prebrure soiulion (Pls. 

5.2; 5.3). Canpasted layers of insoluble inaterid along slylolites 

provided aites for growth of ODiwites 11 and I11 throughout burial. 

Epigenetic dolomites preceded end follnred sulphide minereiizatian 

as part of a tectono-hydrothed event. These dolmiter cemented 

fractures and replaced mrrounding carbonates following several fractur- 

ing events. extenhive secondary soiution preceded rulphlde minsrsiira- 

tion end, to a leseer degree, past-ore Wloaites V and VI. 

After pervasive Wlmite V a wide variety ot minerals precipitated in 

pares. The aaqxence of this mineralization is estimated as Pollovs: 

' [I) Saddle Wlomite 8; (2) msgacrystaliine calcite; (3) gypsum, barita. 

ceiestita and fluorite; (4) lnsrcaslte during and after scaimhedrai 

calcite; (5) galena; (6) red euhedrai sphslerite; (7) pyrobitunen; and 

(8) hsnatite. These crystals &obably precipitated from hydrothermal 

fluids at depth as pymbitmen fomd frm them1 cracking of hydrocar- 

bans (Evans et el., 1971). Late fault-reisted doimitar (Vll) occurred 

duriw or after regional uplift. Late calcites with yellow CL. the 

last ~9 cents, probably were coeval with similar Carboniferous 

cements (saundars and Strong, 1986).

5.11 hmmllry and Disoussim of Plnid Inclusion Data 

b.icrothemetric mearur-nts of fluid lnclurians ample e rpec- 

tm of parsgenetic stages frm early calcite ceaeots to spbaleritrs, 

saddle dolomites and late non-luminescent calcites (Appendix PI. hli 

carbonates and sphalsrites crystallized ftm hwcrseiine brines. 

Depression of ice mlting teweratures to -loOc LO -3vc mwly !he 

presence of 180 to 220 ppm total dissolved reite. Pluid lnclvsianr 

honogenize at lw to maderate terperaturea of 60' to 180°C. Ertinatcd 

burial depths of 2 to 3 kn for epigenstic minerals implies that car- 

rected honogenization tweratures should be 20. to 30°C laer (Potter, 

1977). 

A thermal high of 160' to 180DC during early sphalerite crystal- 

lization was prseded by cooler, but mderste, formtion temperatures 

with a mde of llS°C during late limestone diagsnesis and Lollwed by a 

IB.' 

omling trend to a rde of 115°C T,. Lor late sphaleriter and mst saddle 

doimites to s mde of 55% for late calcites and late fault-related 

dolostones (Pig. 5.7). me hiogenization temperatures of early 

calcites were probably reset hiring mluinnun burial (Prezbindowaki and 

Larere, 1987). 

salinity generally varies inversely vith T,, (Fig. 5.7). Ore stage 

incluaims with hlgh ThSs have 1w.r salinities than late stage in- 

clusions vith Iw %'%. IOL saddle dalmnrte and sphalerite inclu- 

sions, however, have similar salinities around 25 equivalent weigh1 % 

NaC1 and h-enize wer a btoad temperature range fro. 95O to 170DC. 

A-lws lw salinity inclusions vith high and lw T,, probably sample

Figure 5.1 Pluid Inclusion Salinities vs. H-eniretion Temperatures 

Plot of hanajenization temperatures of fluid inclusions versus 

thcir final mlting temerstuns, e mesure of their salinity. Separate 

or overlapping fields of data can be drawn for each crystal stage. 

Early calcite inclusions are less saline than other papulationa. Their 

high Tnta were pmbably reset during burial. Salinities of saddle 

dolomites and aulphides are gMerslly similar and their T,'s overlap. 

Inclusions in late calcites are distinctively different with high 

salinities and lor T,'s. Suggested iaochores are frm Konnerup-Madsen 

(19791 and Lindbla. (1986). They suggest that early ere brines wre 

light cornpared to Ulora found in late sulphides and saddle doldtes. 

More data is needed to eveinate the importanoe of low salinity in- 

clusions.

FLUID INCLUSIONS: SALINITY VS. HOMOGENIZATION TEMPERATURE 

FINAL MELTING 

TEMPERATURE 

(SALINITY) 

0. C 

50- C 100-C 150-C 200' C 

HOMOGENIZATION TEMPERATURE

186 

two or mre separate fluids as suggested by s m' workers 1e.g. Taylor et 

al., 1983; Lindblm. 1986). Populations of inclusions with low nalin- 

iriea and high T..'r occur in am- localities elsewhere on the Northern 

Peninsula (C. Sounders, pers. corn. 1988) 

Pluid inclusions from other HvT sphaierites and gangue carbonales 

outside Nwfoundland also h-enire at temperatures of 90 to 120°C and 

are hyparsaline (20 to 25 equivalent weight I Neci) (Roedder, 1968, 

1977; Leach, 1919; Taylor et 81.. 1983; Richardeon and Plnckney, 1984; 

Lindblom, 1986; nc~aughton and smith, 1986; Gratr and Miara, 1987). 

Inverse relationships between inclusion rallnities and homogenization 

tenpsratures are interpreted as mixmg of tm, solutions; one hot end 

saline, the other cool with In* salinity (Taylor et al.. 1983; Lindbim, 

1986). Conversely, invariant salinities of inclusions are interpreted as 

evidence of precipitation f rm a single fluid (Richardson and Pinckney, 

1984; Gratz and Misra, 1987). Wide ranges in temerature, salinity nnd 

density of fluid inslvsiws at Daniel's Herbmr, more than anything, 

displays vaxlatinn of fluid ompasition through crystallization history 

rather than concrete evidence of fluid mixing. 

5.12 mmcy and Dhweim of annm and Uvbon Isotope ma 

introduction - Oxygen and carbon isotopic data for ail the dolmit- 

es exhibit a pwressive depletion of 6'"O in moat younger cwrtala and 

depletion of 6'"C in late mimite VI and late no"-iuinescent saicites 

(Pig. 5.8, Appendix A). This simple overall trend is complicated in 

detail. (1) s m nattle dolomites of mlmlte I1 type are depleted in

igurc 5.8 ~elative 6"o and 6"c conpositions of the Dolomites 

colparative plats of 6'0 vs. 6'*C values for ell the 

dolomite rypes and calcites (data listed in Appendix A; also fro Comn, 

1982; Haywick, 1984). In Figure 3.m primary limestones olurter between 

-8 and -9 olm 6'*0 and -1 olw 6'"C. 6°C valves in mst dolanites are 

similar. Dolomite I has lhigh 6'"O values (-4 to -6 4001. Dolomite I1 

and 11; range between -6 and -10 olw. 

m Figure 3.88 of @genetic dolmites values. mestage 

saddle Dolomite A has depleted 6"O values (-9 to -11 ojw) cmpered to 

Oole-nite Iv end othsr aystelr of wlmite V (-7 to -9 0100). Serial 

rmplrs of cavity smntr in ore zones (ermva) chwe pmrlresaivrly in 

isotopic conposition im ire s' ige saddle Oolcmite a (-10 to -11 o/w 

6"o. -1 olw 6°C) to late stage Saddle Dolomite A (-10 to -11 o/w 

6'"o. -2 olm 6'"C) to Saddle Oolomite 8 (-7.5 to -9 o/w b'"0, -2 to -3 

vlar 6°C) to late calcite (-10 to -.I1 6'%, -3 to -4 6'W. 

In Figure 5.9C isotopio .,slue. of late fault-related 

&Idtea (VII) vary widely.

A. EARLY DOLOMITES 

6. EPlGENETlC DOLOMITE1 CALCITE 

i 

arl" 

C. FAULT-RELATED , POST-UPLIFT DOLOMITES 

ar?x - 

,h- 

0 --,.--I 

a ~L-""L--u 

., X --. au*." .. *.D 

rn Urr urmn rern 

-a. * 

,- 

8 0-.. I "IW .".".Y M. 

k

6'"o similar to late saddle dolomites, whereas Dolamiles 111 and 1v arc 

not. (2) samples of oolanitr 111 in the bat Harbour Formiion are 

aeplrted in 6'"C. (3) Some saddle dolomites and late fault-related 

dolomites are neither depleted in 6'"o or 6°C. Other dolostoncs, 

IW 

identified as Dolmite VII, denonstrate e wide range of 6"'o values. It 

1s necessary, therefore, to exaniine.separateiy the data of each 

diagenetic stage. Isotopic ewlutinn is thus described end analyzed 

with respect to four separate hlmitizing system: (1) syngenetic; (2) 

diagenatic mttle dolomites and zoned c-nts; (3) epigenetic tcotono- 

hydrothermal dolomitea: and (4) late fault-related dolomitizstion (Fig. 

5.8). 

muses of Practio~tion - Several fractiomtion lnachanisms operated 

in mnoert to produce ths observed isotopic variations. eoasible 

processes include: (1) equilibrium and kinetic fractionation; (2) 

degree af water-mck interaction or rmk-buffering of Fluids; (3) 

variation with temperature; (4) midation of organic or inorqanic 

oarbon; (5) diffelence of 6'"O fractionation in dolmites comared to 

calcites; and (6) deviation of '*0/'*0 activity ratio Pmm atomic ratio 

of water in saline brines (Taylcr. 1979; Ohto and Rye. 1979; Hoefs, 

1980). 

water-rrrk interaction significantly affects isotopic fractiona- 

tim, particularly because large volmes of fluld cherecteristically 

pass Chrovgh porrrua carbonate mcks (Land. 1980). Weter-rock ratios 

(WIR) express the change in 6'*0 and a'"C as in=-st. of water in an 

ideal e l 4 syst- pan through an aquifer and are represented by the

equation: WjR = log. (6,.~,,., + a . - 6,.,,,i.,) 

( ""'" -. ) 

I~A~*~..Z - 6 =2m.~ + 0 1 

I """ -* 

where the temperature dependent equilibrium c mstant ( a ) 

= . 6 " - 6 . 6 . - ex

~ig~ire 5.9 ~alculeted curves for varying waterlraek ratios ecoording to 

(A) variable 6'*o of the initial fluld and (6) variable fluid tenpera- 

Lure 

(A) curves of 6"c vs. 6'"o foe varying water-rock ratios are 

lotted for interaction between an initial dolomite of -4.5 o/w 6'"O 

and various fluids of initial isotopic c-anpositions ranging from -2 o/m 

lo 4 a/ao 8'*0. In ell cares the fluid temperature is 100DC. Note that 

hpersaline brines (3 0100 S'"0) equilibrets with the rocks at -7.5 

olao, aMilar to the standard cawsition of St. George doloatones. 

(8) Curves of 6'"C vs. 6'-0 for varying water-mk ratios are 

plotted far interaction between an initid dolmite of -4.5 olao 6'*0 

end an initial fluid at Snow. The two ecenarios are different tempera- 

tares 2f 75OC and 100~C. Note that a 25*C change in fluid temperature 

causes a. 3 01- shift in 6"O values, sMler to the difference bctveen 

ore-stage dolmites and other*.

WATERIROCK RATIO CURVES 

FOR VARIABLE INITIAL FLUID 2'0 AND FLUID TEMPERATURE 

192

an opes, fluid-dominated system prqressive c*nent,nl~oh or pul'r. leads 

to decreased wall rock interaction and illcreasing fluid signature in thc 

6''C of the cement (cf. Weyers and Lohrn, 1989). Tltu K"c of ~hc. he 

fluid, also, can be progressively depleted ar CU.,lflI. ralios tncreass 

during oxidation of inorganic or organic carhns in either meleoric 

waters or swbsurface Ihydrocilrbons (Ohmato and Rye, 197'1). 

1.11 

Synoenetic Dolmitization - nnth nicracryslaiiine dolostancs of 111s 

Aguathuna and Catme mmtionr mntsin enriched -4.5 o/w bl*O PIB 

relative to mntemporanwur lire mdstone and uackestone 1-8 o/a, 6"*0 

PDB). The b'"0 enlichnt ~sn be attributed to tw mng several 

possible nechaniwr: (1) 3 to I olau fractionation in cantemporary 

dolomites; or (2) enrichment of 6'"o in near surface pore fluids through 

evaporation. 

Diagenetie Dolomitiration - Dolonite I1 varies bmedly fran nadsra- 

te to depleted 6'"o and has invariant 6°C (Hawick, 1984). Hotlles of 

~rystals with ""depleted 6'% probably originated early in conparison to 

typical =-site crystals. Dapletion of 6'"o values in c-site 

crystals possibly leflects the equilibration between subsurface fluids 

and the host carbonates. The variable 6'*0 valuer can be explained 

several ways: (1) by the mount of water-mk reaction or (2) by 

changing fluid cwsition via mteoric mixing or increasing solxnity 

vith depth. Fluid incivsions E m equant calcite cements imply that 

pore fluids during early burial besme reline (20 equivalent weight % 

NaC1) end warm (IOO'C). &cording to water-mck ratio ceiculations,

saline pore fluids at 10'C end initial 6'% r.t mm lo 12 o/m W 

could react with dolmites of inltiai 6"'0 of -1.5 ojoo WB lo tom 

cry~te~s composed of 6'-u .a to -10 OJOO PDB irig.s.8). 

The feu known 6'"D isotopic values of brightly zoned crystals ol 

~lmite 111 cement are not depleted (-6.5 to -7 0100 POI). ~siile 

inclusions Imply that saline fluids were supersaturated with respect tu 

NsC1. Water-rock ratio calculatione for cquiiibration with raiitla 

fluids vith initial 6"'n of +4 swd and 75-C to 100DC reproduce a 

11.1 

similar range of 6'"O values for cement crystals. cements with deplctcd 

6°C (-2.7 to -4 o/w) pmbabiy precipitated from extrafornational 

fluids which possessed high water-rosk retlos and vrieoced minor wall 

zock iirteractioo. 

Ipiqenetic "~ectona-nvdrothemlii Dolomites - ~rpiacenant mlmlte 

v end early saddle Wlmite A cement display 6'"o depietlon and late 

Saddle Dolwnitea A and B are progressively enriched in 6'"O and depleted 

in 6'"C. Populations of early saddle dolmite have widely variable 6'*0, 

e.9 -1 ojm, -8.5 o/oo. -9 to -10 0100 and -11 oloa PUB. mient 

fluids, as preserved in fluid inclusions, homqsnize at 9O'C to 140eC 

and ara hypersaline (25 equivalent weight a NaC11. Lstc non-luminescent 

calcites, depleted in both 6'"o and 6'"C. are precipitates of dilierent 

highly saline [greater than 25 equivalent weight a ~acl), " sl" (50- to 

70.C) fluids. Sverjen~ky (1981) has explained a similar lsotapic trend 

and paragenetic sequence fm the Upper nirsisaippi valley Dirtrict by 

increased water-rock ratios. 

#ate.-mok ratio calmlations for initial water W"O of SHOW or 12

$loo smm end an initial dolomite 6'"a ul 4.5 cx/w I'D& generates rum1 

rack 6'"o betmen -9 and -11 0100 PUB. 

IQb 

The isotopic data for cpigcnelic 

dolmites suggest that this mdei is too silnple for several reasons. 

(I) Detailed paragenetic sample suites of alddle dolomite cementa 

dmnstrete progressive enrichnt aE 6'"o and dspletion of 6"c (~lq. 

5.9). This trend is not predicted by WIR calculations for a single 

fluid in a closed system. moling or different fluid types could have 

generated there changer. Calwlations shm that a 25-C Iiuid tempera- 

ture variation can effect a 3 per nil change in 6'*0. 

Existence 01 

several 6'*0 ,lopulations of Duimite v and varied fluid inciusion 

cowsitions of Wlmite v support the probatility of several fluid 

types. 'Them1 changes are supported by fluid inciurion data. 

(2) Water-rxk ratio relationships ass- challge in rock isotopic 

composition according to the volume of rluid vith which it has inter- 

acted. ~lthough the wali rock was exposed to greater fluid voluna 

through rim, saddie dolmite and calcite cements rather represent 

incremntel samples of changing pare fluids which probably experienced 

decreasing intoraction with the host raks. Fluid inslurxons and trace 

elements denonstrate the dynamic change in fluid chemistry. 

(3) d he depletion of 6"c correlates with the saddle dolomite 

cement sequence. Progressive cementation probably restrLied interac- 

tion between the fluid end the original bloatone. The cement as e 

result eryatalliaed In eymilibrim with a light carbon [luid und not the 

original dolostone. me light carbon is attributed to the production of 

m, either by midation oE hydmcarbons or reduction of auiphates, both 

knwn to exist.

Port-tectonic fault-mlat.4 dolcraitiratiot~ - Prull-related &lanil- 

es which replaced Ilmestoneu have varied 6'*0 isotopic c-rpaitionr 

between -4 and -11 oloo PDB and minor 6°C dcpletlon (data rrm Camn, 

1982). The Iuuited data on these dolmites suggests that different 

Fluids with varying proportions of meteoric water and connate brine 

muid have mixed along fault equlfcrs and crystallized dolmitcs vilh 

different 6'*0 smpsitians. Models oE water-rock revction between a 

oonstant carbonate rock type and valible initial Eluid 6'"O delnnrtrato 

that meteoric type fluids depleted in 6'"o (-2 doo WOW) generate 

depleted 6'"O 1-11 o/m PDB) in dolomite crystals at equiiibriun. in 

I'lb 

contrast, at8 inltial fornational or oil field brine cnrmhrd in 6'*0 116 

oloo smm) would have dolmltized carbonates st an equlllbrim of -6 

to -7 o/m FOB 6'LO. Alterndti~~ly, the dota set can be viewed as s 

broad field between -4 and -11 oloa PDB 6'"O rather than separate 

populations. In e singular enviromnt ""depleted values would repre- 

sent dolmltization from lhited vater-rock interaction 81th meteoric 

enrich& waters. Depleted doloatones crystallized along mjor faults 

which were conduits for large wolues af uster over en extended tba 

perlod. Lack of 6°C depletion and the replacement nature ot cryetalli- 

ration inplies that fluids ewletely interaoted with the precursor 

carbonate and aptillbrated with the mcll carbon.

5.13 Implications of Trace El-nt Machemistry 

and Cathodolu~in~ssense 

Intmduction - Cancentrations of minor and Lrace el@~ntn in Lhe 

uppet. St. S~orqe Gcoup at Daniel's Herbour are vary Low. This inr 

proverishent relates to the conaistitly gmd stolchimstric structure 

with 49 to 51 nalr % Cam,. Trace element coneentratlons in ex!stele 

ere s-nly at or below the detection limits of the micropmbe. 

Locally, PeO and Nc,o abundance rises to 0.20 to 0.55%. Sr is un- 

detected. variations in Fm and Mno fro. 0.04% to 0.15% ere considered 

significant on the hasis of correlation vith luminescent zones. Whole 

rock atdo absorption analyses of total F~D, vhish range frm 0.20 to 

0.93% include natrix plus crystal iron. 

Stmntim Depletion - variation in strontium concentration is a 

patentially useful indicator of changes in fluid chemistry and the 

crystallization prwer. 1e.y. Land, 1980; veiaec, 1983). characteris- 

tically, late dalmites are depleted relative to early dolostones 1e.g. 

veizer and ~avrvis, 1918; veizer, 1978). ~n the st. George Group 

dololanlnites and nattle dolostones containing Wlositr;~ 1, I1 and 111 

have moderate 135 +SO pp. ahundancas of Sr" cnaared to saddle 

dolomites end coarse spllrry dolmites of Wlmite v vith 66 m 535 ppm 

Sr (Hapick, 19841. 

Several PLOS~SSBS ot. environr:sntel chanyes have been proposed to 

account far this depletion. (1) Early dissolution of aragonite muid 

increase st" in initial dolomitizing fluids. mny mttie dolomites,

hwrver, crystellired at depth long after near surface arogonile 

dissolution (Hapick. 1984). (2) Pure mteoric fluids have small SrlC.3 

ratios relative to early fluids vith >I% sw water. Reactloll wlth 

mteoric water, thus, could reduce Sr content. Xost mndte lluids arid 

ail field brines, however, have elevated Sljca le.4 Whlte, 1963). 

Hypersaline fluid lnclvrions with cacl, suggest that sr" probably urns 

abundant in dolmitiaing waters. (31 Perfect atoichi-try could llave 

prevented trace elmmnt substitution. sr-depleted saddle dolomite6 in 

mst of the St. Gwrge Group in other regions are, however, non-stoich- 

lametric (55 nale % Ca) (Hapick, 1984). (4) Depletion of both near 

surface end deep subsurface limestones and dolostones by recrystailila- 

tion in sr-rich waters requires very low distribution coefficients for 

sr (urn-) OD the crder of 10.- (lend. 1480). Differencss in rate and/or 

1411 

style of dolmitization my have controlled D".. Hottle dolomites (11) 

and zoned dolomites (111) cry~tallized slaly and replaced limestone 

along stylolites with laoderate u"?. Late pervasive and rapid I?) 

dolmitlzation of precursor dolomites and limatoneir occurred et a 

possibls low Dm'. (5) Hsttes and Mountjoy (1980) oalcnlated that 

dolmites insorparate low Sr concentrations when they replace limestones 

under equilibriun conditirns. Replacement dwa not, howver, explain 

the composition of saddle dolmite cements. 

Felm Patios and Cathodolluoinascence - Elevated ooncentrations of 

mngmese and lov Fe"/nn" ratios correlate with lwninessent zones and 

phases. Other minor el-nts 1e.g. Pb", REE's, Zn", Ni") of unknown 

c~ncentration could mntributn as activators, senritizrrs or wenchers

(Macilel. 19861. In mulLipls zoned avionitca 1100 Lo 1700 lyll Hs ond 

Fe"/Mn" raLivs of 0.05 to 0.8 lfmm microprabc data) cocrclille will! 

bl'ight a bands (Fig. 5.41. Bright red CI. Saddle LblwiLc I1 eimilariy 

conlains twice Ule Mn of Saddle Dolomite A (600 pp. colnpsrcd with 250 

1'11, 

ppm) and p ress lover Fe"/Mn" ratios, 0.75 ccmporcd to 1.5. Correla- 

Lions and assumptions about phyricpl-chemical mndilions on tho lr8ris of 

lminescence and limited gmchedatry msL be nude with clniLion (Hallchui, 

1986). Machel has w has~red that besides standard Eh and pH inlcrprc- 

tations, ludnescence is effected by trace element pnrLitioning, organic 

and clay disgenesia and variations in trace element supply in dalmitir- 

ing fluids. 

me dolomite stratigraphy at Daniel's Harbour is sharrcterizd by 

four CL crystal types: (1) fins dull CL (I); I21 blue-zoned and 

replaced r hdr 111); 13) bright multlpie zoned c cnl 11111; and (41 

uniform bright to dull red replacement dolmite end cemnt IIV through 

VIII. The transition frcn dull to bright ronad celnents is canpacable Lo 

burial trends elsewhew (sf. Prank et al., 1982; Grover and Read, 14811. 

A change Era. oxidized to reduced waters wwld all- incorporation ot 

ths rBdllced divalent species of m into dolomite IFrank et al., 19821. 

Multiple zones and coarse pra-fziimg crystals suggest alov crystnlii- 

zation f mm a long resident fluid which undewent fluctuations in eh. 

Earlier dull CL dolomites 1- and 11) may have crysteliired fran oxidized 

waters. Dolomite 11 replaced linestones and nucleated m leyers of 

insolubla material in contrast to cements of later Dolmitc LII. Pores. 

"hioh Dolomite III.siarly cemented, may have been a reduced setting. 

Uniformly bright to dull red luminescence rhnracterizea both fine to

,.. 7,> 

rnv 

l~\eJilrn ~~em~orpl~ls cryrlols nrii coalre cmnl'cryrtaln ol lhr 01 rsn~lc 

dolaalt~s. Rapid, petwsive ~~YBhlli~~tlor~, almllor Lo early 

aolaaitae, could ncmnt for unlIorn htmlneacusce. nnt1gl8neos ncllvnllv~~ 

and #loderole lmn quanchlng produce tho ~mine~ll red al>crtnm. Uotll 

eienents are preae#$L and lnunqoncse mnrielmattt In l&nLilld In lio4dlr. 

Dolomlte 8. Dull red CL Doloallto V, porvilrlve ol'l.1. #icllplbldcs, #lay In 

_& anvlmnmental ly slgnl[lcant. Sllghtly oxidired lloids could Ihova 

11111ted maongilF...c substit~tion. 

Perrooc Dolaalte - Perroan dalaaltcs, revcitled Iby pola>mlum Cord- 

cyanide steln, ars dlutrlbuted laally withln aeverol dolomLLo phases. 

nwng ~~olonlto III typcli lerman dolmdte (2000 LO b000 ppm ro) canontn 

htcrcrystallilte areas ol nguollluno doluli!mlnltes. llad ~ynL~llal 

over(lrrmthe of lunlnescent colennvaus nuelsli in ti!* rock lmtrxii 

breCElas and slylo-nalUaS ul the lover Cilkmhe ~ormotlon. Tile couco 01 

Lhs cewnt in line nguuthunn rormtian ir unknown. Dolonltizatlon amu,#d 

calcite m$cleii appears to ham crreld o microenvlronmant lor re" 

s~bstltutlon in the crystallizati~n of the rim dolmitce. rC preciplto- 

tion were governed by bulk ~olvtion dissqulilbrlun (Vabrer. 1983). the 

chmical mnpsltion would b. contmlled by thln reaction rims around 

c~ystals. Chsrtges it, mncsntratfan of Fe" mid have been affected by 

repid precipitation around nuc1.eii 1e.g. larens, 1981) or elevated 

oxtaatio?. ~Leotial around arystaliizatim centres. 'The iron-rich 

residues 01 the bre~sias and stylolltes provided lmrl surplus of Fe". 

In epigsnetic dolostones, especially Oolaite V, deep discordant 

dolostones and outer marse .parry dolostones ?rz anmlously ferroan

3 1 1 

(1000 to 5WQ pm). Both W l e DUlwILos h and H vmlil~n ai;w?)o .ruoragc 

concentrations of re" 1600 to 3000 ppm). The incrpdre 11, iron n,~ert>- 

t~ation away from centres of dolostone bodles could be related LO 

ravaral variables: (1) decrease in temperature; 0) uridatiun; (11 

change in vatev chemistry; and (4) eetc or precipilrlion dnd dill~~;ilon 

across crystal ~urfasea IVeizer, 1981). 

5.14 Smrary of Dlmite Crystal Types and thsir Bvolution 

Seven generations of dolanites are distinguished Imn dirlerences 

in crystal texture and chemistry. Varieties of crystal textures 

includo: (1) n~crocryrt~lline textur~; (2) very Fine to medium euhcdral 

rhorhs which replace limestones and nucleate arwnd peiaids: (3) 

samrphic dolomites with syntaxial wergrarths and istergrovn, xenolap- 

ic contacts: (4) blocky cmnts; snd ( 5) saddle dolmltes. Iwrtent 

gsochemical variables include: (1) Fe" and Nr ' c:onsentmtion which 

respectively qurnch and activate csthcdoiuminescence; (2) crystal 6"'O 

which traces the fluid source, vaterlmck eqvilibrilm and temperature ot 

czystalliEetion; and (3) Sr" concentration which in progressively 

depleted in late dolomites. 

Dalonite - Mismcrystallinc Aguathuna dololminiteb and very fino 

crystalline Catache dolostones are distinctively enrichsd in 6'*0, -4 to 

-7 O/W PD~, and ST, 85 to i40 pp. licmcry~tais vhlch originated from 

micMdo1rxnite 0. fine lnud nvc1sii campare with "syngeatid' types 

descrlhed elsewhere (Matter, 1967; Behrens and Land, 19721. Fine

quigranuiar crystals, which replace Celoche mdstones, aro texturoliy 

indlst~oguish*,le Em Dolomite I1 crystals. Qield and retmjraphic 

relationships imply eealy doimitization prior 10 tho fornafiott of the 

St. George unconfomity and contewraneous Eine rock matrix breccias. 

Miolnite 11 - Very Eine to €ine crystals pervasively a1Ler rornlor 

burmved mudstonas and vackestoncs to fine sucrosle doiostones and 

medium rhnbs replace micrlte-microspar mttiea in 1in.stone. ubiqui- 

tous dolortone nwttles and some sxtenslve dolostone beds resulted. ?he 

purplish to blue cathodolminescsnce is slightly brighter than "on- 

luminescent Dolomite I crystals. nost doimitea post-dain Miumita 1 

because: I11 crystals replace diegenetic miemspar ca?sile, and (2) 

many crystals have grown near or within stylolites. Pressure solution 

.!U< 

Features developed a1 a minimum depth of 300 Lo I000 ntlatn.~. sLy.ui1tc- 

related doiolcites inply doimitiration by one or mre pmcrsses: (1) 

crystallization during chemical cmpaction; (2) flrrid mement along 

stylalites; and I31 preferred crystelliretion aro~nd organic carbon and 

other styloiile residues. Comn replacement and cormsion tcrtures 

signify that crystals nucleated in the shallow subsurface and hccme 

matastable at depth. OiEferences between Daniel's Harbour blue CL 

dolcmites and m t au Port finely zoned bright CL cryrt,%ls implies local 

variations in water chemistry or tim of crysi.lliratiol.. 

Isotopic signature differs fmn mlonlte I md 111. Widoly variant 

6'*0 between -5 and -10 0100 PUB pmbilbly relates to long tern crystal- 

lization fmn fluids of diffemnt 6'"o cnp~sition and equilibration of 

oriqinal sca water pDre fluids with the mk. Sanples wjth enriched

?m 

6'"O and Sr arc comparable Lo Dolomite 1 and probably crystallircd early 

during diagenesis. Rare petrographic features support ttin conclusion. 

POI: example, calaite c ants which pre-date pressure soh!tnat~ truncate 

sme early Dolomite I1 crystals (Hayvisk, 1984). 

Dolomite 111 - Fracturing and solution pmdueod a pomeahle nciwrk 

uf fractures and solution and lntersryatolline pores which was camsntcd 

by minor m n t s Dolanrite 111. In particular, fracturing along the 

faulted margins of fine rock matrix breccia. generated local co!#cenLro- 

tions of fracture pores. Dolmfia 111 pervasively crystalllzcd in the 

pornus brBcoias surmundinn thess fractures. Thane zoned dolanjlrn also 

precipitated xbiymitoualy in stratigraphic dolostones and along stylo- 

lites in limestones where verv fine to medilmrsizsd, block", finely 

zoned crystals srnented pores, and thin syntaxial overgrowths partially 

replaced Dolmite I1 r Ms. Uediun-sired crystals selectively replaced 

want calcites in burrvw cores and fractures. Dolomite 111 was 

subsequently stale and resistent to dissolution during stages of lato 

dolomitizetiun. ~lthough a minor constituent, Dolonite II! cemsnts are 

s peragenetis lnarbr of rubsurface dissolution, fracturing end change Is 

pore fluid chemistry. 

The nvnoruvs thin cement layers precipitated over a long yeriod of 

fluctuating pore fluid ~hemistq. Reducing pore waters clmtrihutrd to 

nn" concentration ii bright c-nta. Famationel brines saturated with 

salt and enriched 6'*0 (+4 ojoo sum) pmbebly account l ~ r the un- 

depleted crystal B'"0 (-6 to -1 oloo WB). Light cerbcn c ants 

precipitated in epilfbriun with the fluid.

?O.I 

~olc~~nila IV - upper catmhe coarse dolostone cmplrxes cryrtolli~cd 

during several successive generations of tectonic fracture and fluid 

migralion (Chapter 9). 111 !he first of threo phases o I dulamitiznlion, 

medium nemrphic crystals and intarcrystalline cements of rcd CL 

Dolomite IV cryrteliizcd locally ingrainstoons. burrwid sackestonas, 

some Asvsthuna breccia horizons, end extensive portwns or dwp dircor- 

dant dolostonas. crystals cnnnanly replaced earliar dolornitus. 

Althwgh only relict patches of Uoimile Iv remain in pseudobreccias, 

Dalam;Le Iv's ubiquilms distribution in gray daibdtones avggests that 

most of the marae dolostone conple~es were dolam~tiaed durinq thls 

phase and later were extensively replaced by Doimite V. Intermediate 

crystal 6'"o of -7.5 to -8.5 aloo PDB implies that Dolomite LV crystal- 

lized from formational brines in eguilibriuln with the host carbonate 

rock. Xsnotopic textures suggest that these were hydrotbemai 

dolonitas. 

-- nolomite V - Faults, fractures and solution by fluids along there 

fractured ptlths collectively crcated extensive porosi:y in the Upper 

Catoche Fornation subseyment to crystallization of Dolomite I V. 

Multiple layers of sulphides partially celmnt these secondary pares and 

==place dolestones. Several genepations of fractures interrupt and 

pat-date sulphide presipitetion. (Details of this g*.li-y are deacrib- 

ed in Part V.: Dlwite v, the dominant spigenetic dolomite, extensive- 

ly c-nts msopres and replaces precursor dolostones and limestones. 

Coarse to ~negacryrtalline idiutopic saddle dolomites CemenL pores. 

Xenotopio replac-nt crystals grade between fine to medium dolomites

with plane extinction to nedium and coarse kaddle dolaniles with 

u~dulose extinction. euhedral rhmbr ol replacement saddie dolaaite 

embedded in residues replaos geopetai muds at the base oI tormsr porcs. 

UlarSB sparry dolostones replase limestones at the periphery of marre 

dolostone c ~ l e ~ e s Within . these latter dolostones Cine lntlle 

dolaite crystsis are nemrphored dnd intcmttlr. lilaestones are 

replaced by equigranuler fine to coarse saddle dolomites which have 

nucleated srovnd very fine pelolds. In replacemant dolaatones uniform 

luminescence end masses of fine nucleated crystals inply ralatively 

rapid dolomitizatien. coarse zoned pore cants on the other hand, 

appear to have crystallized graduaily. 

~luid-rock equilibrium at elevated tenpsratures prdueed deplete4 

crystal 6'"O 01 -9 to -11 0100 PDB. Variable tevretures and fluid 

cmpositions may have generated crystals of varying 6'"o cmposition, 

betwscn -6.5 and -11 0100 €96. Late cements were enriched one per mil 

durinq late stage cooling. Cements isolated the fluid from interaction 

with the precursor dolostone such that latest crystals vith depleted 

I03 

6°C were in equilibrium vith l'ght fluid carbon. Sr, 40 to 70 ppn, was 

dapleted by (1) partitioning during neomrphism of dolomite and (2) 

cycling and equilibration of fluids within the ssdimntary pile. law Sr 

content may have resulted from s low D"- during psrvasive axd rapid 

crystallization. 

Dlomite VI - Megacrystalline Dolomite VI locally cemnted mso- 

and mapores and fumed ubiquitous thin wergmvths after late fractur- 

ins and brecciation of veins and dolostonen. The =dined influenca of

increased fluid-mck IRKLiM, cooling, long fluid residence in pores, 

plmgreaaive cementation ad change in fluid source, helped to enrich 

crystal 8'*0 and deplete crystal 6'"C. In particular, the cooling ol 

fomtianal fluids was s >major contributor to 6"'o enrichment and, as 

cementation limited host mck-fluid interaction late cryntals took on 

the light carbw pignature of the fluids. Reducing conditions, which 

developed during isolation end decreased rates of water flw, led to 

Hn" substitution in the bright CL dolonrites. Further fluid waling, 

salinity increase and oxidation led to the crystallization of late 

cal~itea and aulphates. 

Ooldte VII - Wring dnd aubasquent to late regional faulting and 

displacsmnt, fine to medium crystalline Dolomite VII replimed lim- 

stonen peripheral to late regional faults. luhedral crystals nucleated 

on fine pcloids and left intercrystalline parosiry. Solution along 

stylolites and oalcite spar left distinctive mesopoms which were 

partially cmentad by saddle dolmite and late luminescent calcits. 

Variable sources of pare fluids fram connate brines to iaet-ric waters 

produced widely variaot crystal 6'"O of -4 to -13 o/oa PDB. 

706

6 AND WIl% SJLFLQTS PB3AaSIS 

sulphides were precipitated wlth epigenetic dolomites. On stage 

sulphideo partially cement vain8 and mres which out dolostones of 

Dolmite N and they predate Saddle Oolaaite A (P1. 6.la.g). The ore 

stage thns represents only a mll portion of the paragenetic sequence 

dicus~ed in chapter 5. SIX discernible crystal types are stratified as 

m~ltilayered millimtre thick omants and c-site crystal clusters in 

a variety of pore types, e.g. veins. cavities and wgs. Veins and 

fomr large pores prrswe the most cwlete stratigraphy of these 

~rystal types. 'mo gmps of early end late sulphides are separated by 

a signifioant phase of ftatasturing and bnosistion. no younger crystal 

tmes, galena and auhedral red sphalerite crystals post-date saddle 

dolomite cementa (Table 6.1, fig. 6.1). 

Cryshl types are distinguished by mlaurs: red. tan, brown, 

yellow, yellow-bmm to ahre, end yell* crystals with black patches. 

Each crystal type possesses a distinctive sonbination of crystal habit, 

trace element and sulphur isotope conpsition end fluid inslusian 

hmgenisetion t-ratures (Pig. 6.11. Table 6.1 outlines these 

aspects for nine crystal typs. Discussion of each crystal type in the 

following sections is divided into petrography and diatribution, 

geochemistry, fluid inclusions, evidence of timing and Interpretation. 

General di~cussions at the end of the chapter swer topics of fluid

Plate 6.1 Colaur Phases of Sphalerite 

a. colloforrn early sphalcrites line the walls of a vein fonn the L 

700s which is occluded by Saddle mlmites A (gray) and B (white). The 

~earlicst aulphidee are layers of pyrite and yellow aphalerite followed 

by rd-brown to tan-brawn fibrous sphalsrite and prismatic, yellow 

crystals with layers of bmn orystallites. Saddle Dlomite B cements a 

breccia of earlier dolmiter end sphaleriten. Scale in milliastres. 

b. The core of a 0ryBtsl rosette Contains plwchmie bmrn aeeor 

zones typical of tan-brow aphalerite. PI. 6.2a presents a larger scale 

prspective. Smpla f m the K Zone. 1 m scale. 

c. Pleochroio sector zones conononly occur in layers, relics of early 

crystallites that are now incorporated by coersa. elongate crystals. A 

close-up of thin bands in yellow nphsleritc in PI. 6.1. 1 m scale. 

d. Cross-hatched twinning (gray) in early fihmur sphderites (under 

plarired translnitted light) overprints Eibmus pleashmic incluaiona 

Irea-broun). Quarts (white) mours between dendrites. 100 lua scale. 

c. Late yellow-bram sphphalerites replace dolostones (brown) and are 

wsrpmnn by coarse, prismatic a n t o of yell-black rphalerites with 

black hector zones. Zoned Saddle Dlmite A c-nts over the sphalerite 

and is follwed by Saddle Dlmite B which cements i breccia of yellow-

.!IU 

black rphelerite and Saddle Dolmitr I. Swle Irom UUtl b.10 a[ Lhc Long 

Hole Stope of the central L Zone (lacation in Piqs. 1.4, 10.2 itnd 12.5). 

Scale ," rn111h"etr*a. 

f. areccia blmke of early massive, ten-brown rpl~eleri!e (I) arc 

rhed by late yellnr-brown sphalerite 12). all of which 1s Ir.ctlrre.4, 

dilated end cemented by saddle delmite. An underground wall in the 

east end of the T Zone (location i n Figs. 1.4 and 10.1). Scale in 

tenths of feet. 

g. Late spheleritea form "snow-on-the-mf" deposits on the bases of 

subhorironteI veins. Crystal msettes at the top are probably breccia 

fragments with ovaqrowtha (similar to P1. b.1e.h). An underground wall 

frm the southern drift of the west L lone. Red knife measures B an. 

h. Faceted, blue-white CL and hM, no"-luminescent rphelerite 

wergmms a sphalerits fragment surrounded by Saddle Dolaaits B cement 

which lmincrcer red. This dolomite flllr em11 solution pores In the 

older generation of sphelerite. Cathodalminesence photmlcrogreph of 

s sphalsrite fragnent in PI. 6.la. 250 la. scale.

ig~~n 6.1 paregenesis of Pigenetic sulphides, nolomites and Calcite 

A cmplete epigenstic sequence of pore cements is illus- 

trated on the left. me cmcnt stratigraphy of early and late sphaler- 

itlts and saddle oolmitsa A and B correletes thmughout the mine area. 

lwortant implications of this oorrelation are dia~usacd in Chaetsra 12 

and 14. Early and Late Sphalerftes cmmniy occupy separate vein 

sy~tems, hw~er. and only locally werlap (illustrated in Fig.12.51.. 

P1. 6.la shm Early Sphalerites follaved by Saddle Doldtes A and 8. 

In Pls. 6.ie and 6.19 Late Sphalerites are svccssded by both saddle 

dolmites. The tvo sphalsrite stages m dap in P1. 6.lf. 

variations in gemhemistry and homgsniretion tmppratures of 

fluid inclusions are displayed on the right. 6'.s values of sulphides 

r,enerelly decrease through the parsgenetic sequence. Imn is abundant 

in early svlphider in contrast to oaMm content which increases in 

late sphaleriter. Imn increases is late saddle dolomites. Honageniza- 

tion temperatures pmgrssrively decrease thmugh the parageneti. 

seymsnse. Note that T. des of late sulphides and saddle Dolmite A 

are riailar.

lnclusionr, sulphur and lead isotopes and an overview of Lhe sulphldc 

paragenesis. A description of Lhe setting of tne svlphidea is deve1qed 

in Part V and is based en the paragenetis relationships estabiislad in 

this and the previous chapter. Ore zones, referred to in thc rsxt, are 

locatzd on the map of the mine area (Fig. 1.4). 

6.2 analytical ll.thode 

Thin sections were finely end doubly polishod with 0.001 a. grit 

to improve detail for emmlnation under plane and polrrizsd light. 

Rbvndmoe of Cd, Fe, N, Aq, Zn and S were examined on detailed traver- 

21.1 

ses on the JBOL electmn probe microanalyzer using the Nagic Pmgrm For 

sulphide standards. No other significant elements were ikatlfied by 

multi-element ICP geochemical analyses and hld-matter KDAX on the 

esenning electton micmrcope. mnty-twr, analyses of sulphur isotopes 

(ceochmn Laboratories) checked eight ~ulphide phases and revs~al 

solphates. Micmthenaxnetric measu-nts of 160 t n phase fluid 

inclusions yere urreied out on a Fluid Ins. Digital Freezing and heating 

stage. 

Petmgrahy and Distribution - Very fine Franboidsl, or hexagonal, 

crystals of pyrite are dissemineted in gray dolortone beds or mottles 

within pseudobreccia [Pl. 6.2~). Cryatals cormnly coalesce in m-thick 

rim around pseudobreccia mottles (PI. 6.2f). Outer crystals of these

a. 

riare 6.2 Early Pyrite, Rerl and ran-bram Sphalerites 

crystel msettcs of tan-bmn sphslrrite porssrs replacive cores 

with fibrous, pleffihmic brown sector zones and outer rims of prismatic 

lo equant ycliw rphaletite. Sqle f m the K mne. 5 m scale. 

h. 

nendritis grnths ef early red sphalsrite are overgrown by -110- 

form fibrous ten-hmm to prismatic yellow sphalaiite. sample fm. the 

H mne. 5 om scale. 

c. Very fine, Eraohidel pyrites (grey) a n disaeainated in dolcrmits 

(black) and interlayered with whalerite (white). This is e back 

scatter eleotror! i~age f m the SEM. Sample f m the L Zone, sane as 

PI. &la. 1 m scale. 

d. Fibrous crystals of tsn-brm sphalerits. PI reflected light view 

of an acid-etohed polished surfecs. sample frm the L mne, same as P1. 

&la. 250 pm scale. 

e. I probabls dissolution surface (arrar) between fibmus crystals in 

the lower right and later primtic ones in th- upper left. Swle f m 

the L Zone, sane imge as in P1. 6.26. 11 reflected light view of an 

acid-etched surface. 1 m scale. 

f. Pyrite (blacK) m urs ar thick byen on top of gray dolostone 

mottles (gray) and as disseminated cryetels around the remining edges. 

Saddle dolomite (white) occludes the pores. L mne. 1 ap scale.

ims cmsnt sutfases of wgs; the inner ones precipitate along inter- 

crystalline pores and also replaoe dolomite. Pyrite and marly sphaler- 

lteb on top of dolo~tons frawente, wattles and tho bases of horizontal 

veins grow in a patter. refrrred to as "mow-on-the-mf: (Met and 

Hook. 1950) (PI. 6.2f). Coaraon dissehinstad crystals within doloscones 

fill intarcrystalline pores and eon poikilotopic inolusions within 

yourtger dolmitc (v) (PI. 6.29). 

~eoshemistry - Positive 6'*S values oE 23.1 to 23.1 o/m are 

211 

mOpDarable to swenetis eally sphaleritee with values ranging Crm 22 to 

21.5 olm (Fig. 6.1, Appendix D). No other geochemical data have been 

mllected from pyrites. 

. -- Evidenoonce of Ti.ina - Pyrite form the first sulphide crystale 

along the edges of meaqores and in lusoeeded by a sewnt semrenco of 

pale yellow, red, ta~brnm end yellow sphalezite (P1. 6.lal. Pale 

yeliw mhalerfte is omnly essociatad and intercalated with Pyrite 

(PI. 6.20). 

Internretation - Very fine crystalline py~ite precipitated before 

mrt sphalarite. Pals prllav imn-poor sphalerites with similar 6'-S 

rreluma 123 O/OD) precipitated after pyrite. Association of pyrite with 

gray dobatone nattl.8 end beds implies that reridusa within the 

dolostones could have pmvided fmn, sulphide nucleii or H,S in reduo- 

tiao of sulphates by organic. material.

6.1 ~a.1~ Red sphlerite 

Petrwraph~ nd Distribution - Nicrocryrtaliinc rn very line 

fibrous red to black to gray-bmn crystals ocrnr in three habits: (1) 

nucleii of rosettes I rm in dismetsr; (2) linked oryatals Encircling 

dolostone mottles; and (3) inclvriona and interstitial cryatala within 

aolostonea (Pls. 6.lb; 6.2a). Eeriy red sphalorites typically surmuod 

dolostone oottlss, partially replace dolmltea and co-lesca to form 

rosettes. Very fine Eibmvs crystals radiate 5 to 10 m from corer of 

crystal rosettes as dsndritic growths and are concentrically overgrown 

by mn to m thick bands of fibrous; ten-brown and prismtic yellow 

sphalsritea (PI. 6.2b). Under polarized light in doubly polished thin 

sections lirmellar twinning is visible parallel to long crystal axes of 

21s 

the fibmus forms (PI. 6.ld). This nicmstructure overpdnts fibrous to 

dendritis red bmm to black pleochmic colouration, prt of which 

cmprisas very fine miarometre-eid dark inclusions. Pine evhedral 

quarts crystals an, included within and between sphalerites. Coarse 

galena camoly is associated with red sphalerita which it partially 

replaces. Red sphalerita form massive beds in n e w erratic lenses 

in the uppar paxts of ore zones and nuclei1 d Ewaite 8phalsziten al- 

sewhere. maaive beds contain pyrite and minor galena, and generally 

are eemnted aod replaced 41 only minor saddle dolmite. 

Geoshemistq - Imo enriched I1 to 5% PeO) early sphalerites leek 

detectable oadim and contain minor traces of 0.1% copper and 0.1% 

silver (~ig. 6.1. wpendix 0). Positive C'S veluss P m tm smles of

15 ~/rn and 27.4 o a, arc comparable to later Lan-brwn sphaleritcs 

:!I9 

(Pig. 6.1. Appendix Dl. Associated gelenas hove lighter h*"S values I21 

olrm to 15 VIOO). 

midense -- of % - ~ibrous re4 oryslels am the oarllorl 

sphphalerites. Locally red sphalerites cement over or ere interlayered 

with earlier pyrits (PIS. 6.la and 6.20) and fibrous tan-brown and 

prismatic yellav crystals form younger, outer rims on -n rosettes 

(Pls. 6.la and 6.2b). 

~ntemretation - Imn-rich, fine, red sphelerite nucleated on many 

points in d i m to coarse grey dolostanas and rapidly accreted radist- 

ing and brmching fibmus and dsndritic grwthr and mismcryrtaliine 

layers. These crystal forms with abundant impurities ere characteristic 

of rapid crystallization (e.g., Buckley, 1951). nassive beds rsplaced 

gray dolostone and were subject to minor subsequent solution and 

cemntation by later sphaierites snd saddle dolmite. Disseminated 

orystals grew on mesopores in surmunding beds and fomd nvclcii for 

msettas of later tan-brown and yellov sphalerites. 

Pet-raohy and Distribution - Tenlbmm sphalerites acour as 

dissdnated individual fine crystals. coqoaite msettes and discon- 

tinuous millhetre-thick Isminations (Pls. 6.la.b; 6.2a). Individual 

crystals are dispersed wng intercrystalline pares of gray dolostones.

Crystal rosettes, 5 fo 20 m in diameter. vary t m dispersed cluslcra 

amund lneaoporss to malesfed spheres in beds of mssive, b mn 

aphslsrlte. minabd sphalerite. cement horizontal veins and sheet 

cavities (PI. 6.w. marha crystals, 0.5 m wido by 1 to 2 m Long, 

which radiate outwards fro. dolostone nottlcs, are stubby, triangular 

forms with nsrmv bases and broad outer ends (PI. 6.lb.c). A Cibmus 

texture is rnacrorcDpically visible as alternating plsochmic b mn end 

tan crystals (PI. 6.2b, c). Similar to the red crystals, ths brown 

colmr is acquired Em inclusions of iron-rich impurities. The bmrn 

crystals are concentrated at the base of rosettes and along separate 

multiple growth bands (Pls. 6.la.b; 6.2a.b). A11 crystals have a 

fibrous to cross-hatched lmllar twinning which ovsrprints the colaur 

fabric (PI. 6.16). 

>?n 

Fihmus tanlbmwn crystals are ubiquitous throughout ore lenses of 

early sphalerite. They locally €om massive, brown sphalerite beds 

along fracture =ones where crystal rosettes replace up to tn-thirds of 

mars= gray dolostone beds. 

Geochemistre - These relatively pure sphalerites contain FaO 

rwing between 0.5 and 2.O%, but no other measureable traces (Pig. 6.1, 

nppendiv E). Sulphur isotope ratios of 27 to 28 olw Bas are heavier 

than later rehalerites by 2 to 10 per mil (Pig. 6.1. Appendix D). 

Tested awlss m e frm deep stratigraphic ore in the western C and 

eastern T zones (location, Fig. 1.4).

-- 

Fluid Inclusions - Five fluid inclusions ho~nogenirc oL man 

221 

temperatures IT,,) of 141°C with a range frm 1ZPE to 155°C and sallnity 

0E 24 equivalent weight I NaCl (Pigs. 6.1, 6.2, Appendix I). Irregular 

shaped dark inclusions are associated with pleochrois aoner in these and 

yuunger sphalerite crystals. 

-- Evidenoe of Tidnq - Fibmus tanjbrovn sphalerites lie sequential- 

iy between early red and prismatic yeilow crystals (Pls. &la; 6.2b). 

Tm-brown crystals for. the cores of rossttes outside the range of aarly 

red cryetals (PI. 6.2a). 

Intaroretation - Tan-hmn sphelerite precipitated rapidly and 

extensively in potws dolostonw, veins and large solution pores. Both 

the fibrous crystal form and layers of pleochmis bmn rphalerlte imply 

rapid grorth rates 1e.g.. luckiey, 1951). Centimtre-scale crystal 

rosettes malesoed irm nmemus nuclestion rites on surfacer of 

dolostone mttler. Ilsewhsrs, fine crystals pracipitsted as nvlltiple 

m-thin iminations in extenrive horizontal cavities. 

Petmraohy and Distribution - Yellow sphalerites am ubirmilous 

throughout the mine area in early rulphide bodies. They -cur in four 

different habits: (1) dirsmhated 1 to 3 an thick crystal clusters 

munding gray dolostons mttles In pasudohreccla: 12) 2 to 5 on thick 

auitilayared coliofom growth bands along vein walls and fomr cavities

Pisure 5.1 Fluid Inclueion Dab from Sphaleritas 

l'hc histogrents display eutectic, melting and h-eniastion 

Lemperetvres for fluid inclusions in ephalerites. Data is listed in 

Appendix I'.

(PI. 6.lal; (3) nasvive crystallizaLion of up to two-thilds or coarse 

224 

dolostone beds by 5 to 10 m thick crystal canporites and mscttes uhicl, 

cement microcavities and partially replace dolostones (PI. 6.2o); and 

(4) dirsmimted fine to medim euhedral crystals wlLhin gray mottled 

and lminated geopetai dolostone (PI. 6.3e). 

The ooarse pale yellow crystals, in contreat to earlier fine 

fibrous sphalerites, have gram in extensive opsn vugs and veins (Pls. 

6.1% 6.2a). C-axes of elongate prismatic orystals are oriented no-1 

to void walls (PI. 6.3a.b). A microstructure of radial and inverted 

twin fabrics of nillhtre long lenellae contrast with the short fibmus 

and cross-hatohea l-llae of earlier sulphidaa. Post-crystaiiization 

freturea around the outer edge of crystals include (1) cross-cutting 

isotropic twin lamellee; (2) fractures emmnted by saddle dolomite and 

late lminsacent sphaieriter; end (3) corrosion of crystal surfaces 

prior to saddle dolomite omentation. 

80th fibrous t anlhm and pale yellow rphalerites contain milli- 

metre-thiok gmwth bands of alternating in colwr f m mixed tan and 

brovn to llcnogeneovc brown to yellow crystals (PI. 6.13). A microstra- 

tigraphy of multiple paired bands and nicmcrystaliine layers tracsd 

slw ore zones and th-hwt the mi- area imply that precipitation of 

millhtre-thin deposits is regional. This dcrostretigraphy is 

illustrated sohemtically in Fig. 6.1. Stratigraphy observed in the T 

and I, zones (PI. 6.le) can be correlated up to 7 !m sway in the other 

zone8 (PI. 6.2% X m e; PI. 6.2b. H zone) (locations on Pig. 1.4). 

similar phemna are observed in the Upper Mississippi valley District 

of Wisconsin (mclhens et el., 1980).

a. Gmth layers of prismatic crystals are seen on acid etohed 

polished rorfacss in oblique reflected light (Wmrski Interference). 

sample Prom the L Zone (Pl. 6.la; Pig. 1.4). 1 ma scale. 

b. mica1 prismatic yellow crystals in contact vith saddle dolmlte 

cement in the upper left. sample f m the P Zone (Pig. 1.4). 1 m 

scale. 

c. spherical fluid inclusions, 2 to 15 !m in diameter, fmn the B zone 

(Pig. 1.4) have high hnnogenieation temperatures (lWsC to 18S°C). 25 

IM scale. 

d. Fluid inclusions in PI. 6.3d are evenly distributed thmugh 

patches like this one. 100 !m scale. 

r. Disseminated, equant yellow crystals occur at dolomite crystal 

boundaries. Saddle dolomite cants a late dilatant fracture. sample 

f m the P Zone (Pig. 1.4). 1 m scale.

Deochmistry - The yellow sphalerites characteristically contain 

laisor iron (0.20% FaO) end moderate cadmium (0.20 to 0.35% OdO)(Tnbic 

6.1; Fig. 6.1, appendix El. Intercalated brown sphaicritcs en rele- 

tively iron-rich (0.8 to 1.5% FeO) and cadmium pmr (0.051 CdO). 

sulphur isotope data for yellov sphelentes frm this study and 

coma (lsez) range widely ht*reen 25 o/w and 20.5 oleo @'% and have o 

nleen value of 22.4 o/w 6'.S (Fig. 6.1, Appendix 0). Teat swles 

suggest that crystals in peripheral areas are depleted in :"S relative 

227 

to wergmrths of early aphalerits rosettes. Late brmn spholerites em. 

the K Zone (Fig. 1.4) possess heavier 6=*S values (23 olao) than 

earlier, underlyiw yellow crystals with 21 ola, V"S. 

-- 

Fluid Inclusions - Abundant two phase fluid inclusions, I to 10 pm 

in size, occur in yellow rphaleritsa of the B and H Zones (Fig. 1.4). 

They are hypersaline and hmgeniee at a high man and nade of IlYC 

(PI. 6.3c.d). Hoooganhation temperatures raw* E m 150°C to 1 8 s 

(Figs. 6.1, 6.2, Appendix F). Salinitiss range emm 20 to 21 equivalent 

4t. % Nacl (rig. 6.2). Rnmlous lower temperature inclusions, llVC 

T,,, have relatively lm salinities of 20 eguiv. vgt. % NaC1. In 

contrast to inclusions f m tha B and H Zones, those fmm on F Zone 

sample (Pig. 1.4) have lover hmgeni~atisn tweratures of 92" to 115°C 

and comparable high salinities (Pig. 6.3). 

Evidence of Thins - Yellw sphalerite comnly eoms wergmwths 

on tan-bmun whaleriten (Pls. 6.la; 6.2a.b). Solutlon contacts occur 

between there sphalerites (PI. 6.2e). Yellow sphalerites aleo xurr in

Figure 6.3 Distribution of Fluid Inclusion H~mgsnization Tegeretures 

in the mine *rea 

Uighest hmgenization tweratercs (110' to 115') occur 

losally in early yelm sphalarites in the B and H Zones. Sinilar 

sphelerites have lmer T,'r elsewhere: 92' to 115' in the P Zone and 

138- to 145' in the L Zone. Late yellow-blaL shalerites in the L Zone. 

noted by brackets, vary fmm loOD to 130- in nodal 4. The ore .ones 

are identified in Fig. 1.4.

igare 5.6 Field Relationships Between Early Sphelerites 

and Saddle Dolmite 

present beds of early sphalerite developed in three pha8ea. 

(1) Massive tan-brmn sphalerite ~ryatalliaed in porous dolostoner. 

(2) Yellow ephalerite precipitated in aolution megepares which fanned 

ammd the margins of the earlier ~ulphide bodies. 

(3) Late veins and solution cavities dissected ths sphalerite L%dy 

pi-ior to extensive saddle dolaaite cementation end replacenent. 

This view is the pmsent dey awaranee of a wall in the G Zone 

(location of the zone indicated i n Fig. 1.4).

SPAR BRECCIA 

1:iD"E:ED51'A%n 

YELLOW SPHALERITE 

TAN-BROWN SPWALERITE 

COARSE GRAY DOLOSTONE 

EARLY FUME DOLOSTONE 

EVOLUTION OF AN ORE BED 

2

lacga solution pores outside bodies of Lan-brown sphalerite (Pig. 6.4). 

The prirmtic yellow crystals generally cmnt the cdgoa ot fo!rn.r vugs 

2J1 

that were rubseymsntly filled by saddle dolnite. Ao early b ~ ~ Late n , 

yellow-brown and late yellow-black sphslerites locally ovsrymw yelia 

orystal*. 

Interpretation - Yellow sphaieritea precipitated on roreltca of 

early sphalerites in pomus dolostones. Crystals in largs pares 

coarsened as rates of crystallization and, possibly, Iluid fLou elwd. 

Pleochroic brnm crystals, in contrast, cv,stsllired rapidly bdora 

diffusion of iwueities (e.9.. Buckiey, 1931; nollister. 1970). A 

aillhtra-scale stratigraphy of bmvn and ysllar sphalerite layers 

precipitated througbmt the region. Each layer, with varlabls iron end 

6'.S, regionally preslpitated fro. separate "pulses" of metal-bearing 

fluids. 

Petmsraphy and Distribution - Medium to coarse, U.5 to 10 mn. 

equant crystals are either disseminated thmugh pseudobreccier or 

massively replacs medium cryetallim dolostones in a similar fashion to 

early sphalerites lP1. 6.4a). Fins, fibrous cwtal farms, harmer, are 

absent or dnor. Crystal habits may he categorized into tw groups: 

(1) pore oenentr of linked cwrae primtic crystals which sit on tap of 

and around dolostone wtt1.s and fragments, and on walls of veins (Pi. 

6.le.f.g); llnd (2) mediva to soars. disseminated uyrtals, linked 

dendritia ehllin6 and o-site msettrs which interstitially cement and

a. 

Plale 6.4 bate Sphalerites 

Medium to coarse (200 to 500 p) yellow-bmwn sphalerites walesce 

in nLlDive ore beds. Exmple from the eastern L Zone (Fig. 1.4). 1 m 

scale. 

b. Irregular patches of fluid inclusions in yellow-black sphalerites 

.re associated with large opaque inclusions up to 40 p in diameter. 

The irregular, opaque inclusions possibly represent inclusions destroyed 

during recrystallieation. S-le fmm the L Zone. 100 pm scale. 

E. Micmnetre-sized inclusions comprise black pleochroic, sector zones 

in yellow-black sphalerites. Smple from the L Zone. 100 pin scale. 

d. Two phase fluid inclusions in yellow-black sphalerite range in size 

from 1 to 10 p. Sanple from the L Zone. 25 p scale. 

e. Banded, black sector zones outline crystal f om and tend to occur 

st the base and outer portions of crystals. Smle frm the L Zone. 

500 w soale. 

E. Iung lanellar growth twins, visible in polarized light, overprint 

black sector zones. Smple E m the L Zone. 200 pin scale.

wplace medium crystelline gray :>lostones (PI. 6.4.). Gmvp 1 cemenlx 

are emniy a~s~ciatad with veins and pseudabresola that contain 

239 

greater than one third vhite saddle dolmit~ cement in veins aid paeuda- 

beeccia, in mntrest to group 2 beds which urn'ain only minor spar. 

These sphelerites are colonred an overall light bmwn to yeilow- 

bmwn to orsngiah ochre. Elongate, 1 to 2 m, rectangular to L~.langular 

brw pleochroio patches are scattared throughout the crystals. similar 

to tanlbmm sphaierites. A microstructure of cross-hatched lmblisr 

twinning overprints this fabric. Minor pyrite is locally disseminated 

at the base of crystals at gray dolostans contacts. 

Gemhemlstz - re0 cantent varies from 0.5 to 2.5%. Cadmium 

abunrlancea of 0.2 to 0.6% aro distinctively higher than thore of esriier 

sphalerites (Fig. 6.1, Awndix E). Sulphur isotopes ratios of two 

samplas, in addition to four smples f m Coronss 11982) study, range 

fm L4.5 o/m to 19.9 0100 6"s with a mean at 21.9 olw. This range 

is comparable to that of pale yellow sphalerites (Fig. 6.1, Appandix D). 

The nast positive values occur in the centre of the L Zone and deerease 

tnrsrd the edge of the ore bedy (Fig. 6.5). 

-- 

Pleid Includans - Fluid inclusions have been mneasured in only ons 

sample fm the T-Zone. Hmkyenization tenperatures of six inclusions 

LMge fi-m 125°C to 170°C with the nade st 1392. One inclusion with 

high T, of llO*c is a l a salinity inclusion (-10°C 2. and -30°C T.). 

ma: tempratwe inclusions with a 4, d e of 138°C have rare typical 

high salinity, U1C1,-bsaring fluids (-25-C T. and -60°C 2.) [Pig. 6.1,

~.lgure 6.5 variation of Late Sphelerite d"S P.cLcmse The L ?me 

6"s values for late yellarbrown sphalerite v~cy across the L 

zone (location. ~ig. 1.4). Highest values occur in the ore hody's 

central core to the northwest and the lmeat values ere fmnd on the 

outer flank to the southeast. Three cloaely spaced senples wnstitute a 

detailed profile across the Long Hole :Lope, the thickest portion of the 

L Zone. These swles also suggest that 6 9 vauea Becrease sway from 

the centre of are zones. Data in appendix D and in Won 11982).

VARIATION OF LATE SPHALERITE Sa'S ACROSS THE L ZONE

-- Evidence of - Yellow-brawn sphalerite occurs with yellow- 

blaok crystals in separate ore ie~lssr in the L and T Zones vh~re ~t 

€oms the aarl-t mnts along veins and vugs (PI. 6.le.g) or replece- 

mnt crystals in massive ore beds. These late aulphides also occupy 

veins and pores which locally cut bodies of early sphalcrite. In these 

areas yellow-bmm sphalerite overgrows early yellm crystals and 

precipitates mvnd fragments of massive tan-brow ore (Pi. &if). 

Interprstatbri - Medium to coarse yeliow-brwn crystals nucleated 

on fraotvre and solution pores generated after early aulphides. The 

styis of lnineraliaatim "=led frm aassiva crysteliimation of saatre 

dollostones psripheral to fractures to caarsa crystal growth along 

abundant veins and smitics. me aoerse crystals grew ~mre slovly than 

the early fins, fjbxoun aulphides; but, mre rapidly than late, very 

coarse yellow-blaok crystals. 

Petmrs~hy and Distritntion - Yellow-black sphalerite =cure in 

late sulpbideli and also as ubiquitous, disseminated crystalrwith eariy 

sulphides end mtside ore zones. Pine to mgacryrtnlline, 0.2 to 8 m, 

crystals of pale to bright yellow and black sphalerite vary in habit 

f m disseminated individual crystals to linked prismatic vein and wg 

cents (Pl. 6.19) to massive clusters of crystals which replace ~nediwn

crystalline dolostones (as in PI. 6.4.). There texture. arc conparable 

to those of yellow-bmm crystals (same plates). Caarse crystalline 

open space cuwnta are typical (Pis. 6.le.g; b.4c). 1" Cheee cenents 

palisades of coarse prismatic crystals nucleata on yellow-bmun or line 

yelln* black crystals (Plr. 6.le; 6.4e). 

nlask, plsmhrois seotor zones for. central inclusions ~n yella. 

crystals and give the crystals their distinctive yellow-black colourr- 

tion (Pls. 6.le; 6.4s,e). The sector zones vary fro. cubic to rectan- 

gular, millinetre-scale patches to very thin laminations which outline 

intern1 crystal £aces (el. 6.W. Blsok roriaues along crystal 

cleavage ere outlhed by bright yella sphalerite. The bleck mnes 

comprise lminations of bluish-black pleochmic stein end very line 

139 

bead-ilk* inclusions (Pl. 6.40). Millimetre-long growth tdna overprint 

the sector zones (P1. 6.4f). 

Geochemistry - F a content ranges fmm 0.15 to 0.25% ir pale 

yallow crystals to 0.4 to 0.6% in black patches. Abundsnces of 0.4 to 

0.6% eahim and 0.1 to 0.3% fopper are higher than earlier crystals 

(Fig. 6.1, Appendix E). 

Sulphur imtope ratios, whish range between 18.4 0100 ana 22.4 

01~0, have a lower man value o£ 19.6 olw than earlier aulphides (Pig. 

6.1, Appendi. 0). The most asitive isotopes are assockred with 

crystals in the core of fracture zones, such as the Long Hole Stop of 

the L Zone. The 6".S of yellar-black crystels are one to three per mil 

lighter thao 6'"s of asaaiated, prscvrror pilow-bmvn sphalerites in 

smpled oenent sequenoes (this study; comn, 1982).

-- 

Fluid Inclusions - One to Lventy pm, two phase €laid inclusions 

ere CaC1.-bearing 1% -55°C) with high salinities of 20 to 24 eguivei- 

9.10 

ant weight 8 NaCl and variable hmgenization temperatures between QWC 

and ib8'T with a mean of 12J"U and a rode of 10S'C (PI. 6.dd; Figs. 6.1. 

6.2, Appendix F). Irregular black 10 to 50 pm inclusions, possible 

significant hydrocarbons, ere abundant (PI. 6.4b). 

-- evidence of Timing - Yellow-black crystals am ths last of the 

paragenetic sequence of ~re-forming sphalerites. 'L'hey clearly follow 

yellw-bm crystals in en apparent eontinuaus and gradational preeipi- 

tstion sequence (PI. 6.ie). The faces of yell--black crystals are 

slightly corradsd and werqmm by addle Dolmite a. Minor w-sired 

lead-like sphphalcrite inclusiens oomr looally in Baddla Dolomite A. 

Saddle Dolomite B cmnts frewntr of yellow-black sphalerite vhich 

were broken during postlrre fracturing (PI. 6.18, 9). 

Interpretation - ate cmling are fluids pervaded extensive 

secondary porosity, which developed during earlier fracturing and 

sulphide precipitation. Late precipitation in viderprsad veins and 

:rorous dolostonea occurred as slow growth of coarse crystals with 

depleted iron and "s punctuated by periodic rapid accw~letion of 

inclusion-rich sector zones (Dwty, 1976: Lindblorn, 1986). Cadmim 

enrichment and depleted 3% cheracterised late ore flnids in general.

6.9 Luminescent Sphalelerite OvergmNs 

Thin faceted overrjmwths; or fine euhedral crystals of light blue 

to yellm luminescent to "on-CL sphalerite coat bresciated crystals 

within saddle Dolomite B cement (PI. 6.lh). The bright luminescence 

-ard to the "on-luminescent character af mat of the sphalerite, may 

be attribvtsd to trace variations in minor elements. Nicmpmbe and 

WAX analyses smund rims of crystals did not detect any alewnt 

differences. 

Interpretation - sphalerite frawnts dthin saddle Dolomite B 

contlnusd to grow as lanescent and "on-CL overgnnrths. The faceted 

crystal structure suggests sryrtelliaatian in fluids generally under- 

saturated rith respect to sphalerite. Gregg and Hegni (1981) demn- 

atrated this iaseted crystal stoctura in ore zone aolomites. 

Petrarra~h~e Distribution - Hinor galena oolyrs uith early 

ephalerites in local areas several mstres in dimter. Fine to coarse, 

1 to 5 m dismeter crystals cement ,ugs and intercrystalline paras, and 

partially replace both rehalerite and saddle dolemite. The anhedral 

crystals have slnbayed to irregular "fuzzy" edges, where they replace 

dolmita and aphalerite and penetrate ~rystal cleavage (PI. 6.5a.e). 

~eochmistq - The galena is a pure lead rulphide with no sig-

lrlate b.5 Mtt-Ore Sulphates, Sulphides and Pyrobitmn 

e. Earliest sphelsrite (gray) is left with ragged edges after re- 

placement by dolwite (black) and galana (whits). Latest galena also 

partially corrodes euhedral dolomites. Sample fro. south of the X Zone 

(Fig. 1.4). 1 m scale. 

b. Fl&es of ~ymbituen cover the silrfaes of a vug (arm), 

partially forming s black film an hsddle dolomite crystal faces. 

Collofon sphalerite and neg~sryatalline white saddle dolomite surrounds 

the vug. Siunpls fm the L Zone (Pis. 1.4). &ale in oenthtras. 

c. Fine narcasit- needles (dark ovsqrowths) have grmn on the 

surfacer of saddle dolanites, sample f- the L Bne (Pig. 1.4). Soale 

in millimetres. 

d. Euhedral eelmnites (large crystals) and oelsstites Ism11 

crystals at bttom) are precipit=tad on saddle dolomite and locally 

include mrcasite. Smples from the L and T eonas (Fig. 1.4). 3 no 

sca1s. 

e. Yug-filling galena 0-nt (black) past-dates saddle dolmtte. The 

crystals fill cleavage in the saddle dolmite. Swle f m lead sharing 

south uf the H Zone (Fig. 1.4). 1 on scale.

PLATE 6.5

lnlficant trace olmnt abundance=. 6'9 values range from 15 o/m to 

2'2 0100 and are 1 to 12 per nll lighter than associated sulphides (fig. 

6.1, Rppendix O). 

744 

lead Isotope analyses reported Fmn Four samplas by Svinden ct el. 

(1988)(mndix G) and five samples by Comn (1982) have low urilnoganls 

lead (206 , and 207,) and relatively high thorngenic lead (208,.). 

206- /204,, ratios range between 11.8 and 18.2, 201,,,/204,., aruund 15.1 

and 208,,/204,. between 38.4 and 38.7 (Fig. 6.6a.b). Daniel's Harbour 

data cluster in a tight group end, along with other Catoche Poimation 

data, fom the intsmdiab portion of a positive linear trend for 

galenas hosted by all Cambt'o-Ordovician fomations. Oshna hosted by 

cmbdan strata is the least radiogenic; whereas, crystals in the Table 

Head Gmp have the high-st uranogenic lead (Pig. 6.6a.b). 

206d204, ratios ere plotted vs. 6".s data for Elve samples E m 

mron (1982) and this study (Fig. 6.7). Swler Yth 19 to 22 o/ao 6"s 

tend to be more radiogenic. mese galenas are essoclated with early red 

aphaleritea in upper and central portions of the ore zones. Less 

rediwnlc swles vith 15 to 16 o/oo 6"8 are asraciated with yellon 

sphalerites where they fill RIBS within saddle dolomites (PI. 6.5c). 

-- Evidence OF - Galena fills late pores in saddle &lomite 

(PI. 6.5e) md parrially replsces rphelerite and saddle dolodte (PI. 

6 .J-). :- me relationship betwen galena and ather late mlnerela is 

unkoun.

~igure b.6 Lrad-isotope compositions of Zn-Pb deposits 

in Cadre-Ordovician carbonates of the Northern Peninsula. Zartnvtn and 

Uoe (1981) mde1 gmwth Evrves are shown for reference. Rbb~~vhtions: 

UC, uppar crust; 0, omgene; H, mantle; end LC, lower crust. Daniel's 

Harhur samples plot in the shaded area. Data are f m svinden at al. 

(Isen).

40.0 

n 

* 39.0 

P 

m 

N 

88.0 

TABLE HEAD GROUP d 

-PORT AU PORT GROUP

Pigvro 6.7 ""-PbIX'*Pb of Gslenaa at the nine plotted versus 6"*S 

Galenas at the mine segregate into tw gmupr on the hsis 

of occurrence, 6''s composition and lead cornpsition. Galenas which 

replace early red nphaleritss contain heavy 6 9 values and are slightly 

nwre radiogenic than crystals that oement pores in saddle delmitea. 

Data ere form this study, Comn (1982) and Svlnden et el (1988).

GALENA 

WlTH 

EARLY RED 

SPHALERITE 

GALENA ASSOCIATED 

WlTH YELLOW SPHALERITE 

AND SADDLE DOLOMITE 

17.5 17.7 18.0 18.3

Intezrretation - Galena crystallized after ore sLage sphalerita 

and saddle dolomites and partially replaced bath there predscessars. 

The ordinary or nen-radiogenic nature oE lead at Llunlcl'r Herhr ~n 

similar to nmemus uw deposits (Gulron st al., 1983: Sangstar, i n 

prep.) with tho eIception aE radiwenic, crustally derivsd MW leads of 

midcontinent North hrica (Hey1 et al., 1974). 

Relatively high thorngenic 208, and lor ureneqenic 206,. and 

207, fingerprints the gelena'ti principal source as the evolved high 

grade natmzphis terrane of the Grenvilie basement (Cam", 1982; 

minden, et. sl., 1988). High Th/Pb is not characteristic a€ other 

potential source ereas, e.g., mantle, oceanic crust and sedimantary 

bssins (Ow and Zsrtmm, 1979). Increase in radiwsnic lead with 

stratigraphic height -lies that as the lead-bearing fluids rose they 

assimilated increasing quantities of radiogenic lead Erm: the sedimen- 

tary pile. Variable lead canpositions at stratigraphic horizons are 

1.19 

products of uneven mixing of the two end &era (Sdnden et el., 1988). 

The two separate gmups of galenas at the mine are interpreted to 

contain different proportions of these end ambers. Galenas with mre 

radiogenic (fornational?) Pb auci pritive 8"s values pmbabiy precipi- 

tated from frm fluid. dominated by "basinal" belnes. Replacant oE 

sphalerita alternatively accounted for the sulphur mporition. The 

lisht BAS ~elues of galenas with leas radiogenic Ibasment) eb suggest 

cqstsllizetion f m fluids wrs typical of the bas-nt source. The 

sulphur derived f m this deep swcc was probably light compared to 

that of fomtiond waters. Alternatively the light sulphur of late 

gelenas, sphphalerites and sulphstea !nay be attributed to fractionation

&ring oxidation ot formational fluids. 

251, 

kltornative interprstltions of the lead composttion such as u Lead 

growth curve or secondary isoshron sro mjccted tor ncvcral masons. 

(1) Linear regression analysis of 201,,,/204,,. vs. 206,,./20d,, data giver 

a steepi slope (0.1113) than Phanerozoic lead gmwth ouwer. (2) 

Projection of seoondary irochmns require a source area of 1500 na age, 

greater than that of the radimetric 1250 Ha age of the basemnt. (3) 

mpositianal variation of heterageneoua leads transprtsd end deposited 

in the sedhmntw succession should be independent of stratigraphic 

paartion (Swinden et a1.. 1988). 

6.11 late Red sphalerite 

Petmaraphy - Euhedral coarse to megarrjstalline deep red to 

orange sphaisrite is scattered on open wg surfaces. The crystals sit 

on euhedral saddle dolodtes and share wg surfaces with late pyrite, 

loarearite, calcite, barite and gyp-. 

Geochemistry - Rbvndanees of 0.1 to 0.6% c eMm and 0.1 to 0.3% 

copper -re with the yellow-black rphaleriteb (Appendix E). Variable 

sulphur isotope ornaporitions are light relative to other sphalsrites. 

nn analysi~ of 6"'s by mmn (19821 fmrn an A Zone sample at 10.8 oloo 

@.S, is lighter than a X Zone swle at 20.5 0100 (this study). No 

fluid inelusions were found.

-- 

Evidence of Ti.ing - These latest. sphnleritcs form euhedral cryn- 

tsls in vllgs on the surfaces of saddls dolmiter which thcy post-date. 

Their age relationship to other vllg crystals is unknoun. 

Intereretation - Late red s~haledtes crystallized in open vugs 

after both ore stage sulphides and port-ore saddle dalmite. Allhough 

the trace eirment minpoaition is similar to yellow-black sphalerites, 

6-S isotopaa lighter by up to 0 o/ar iwly e diIFerent. fluid chm- 

istry. 

6.12 Late Pyrite, Wrcaelte and Herrmtite 

2'il 

Similar to late red sphalerite, auhedral oubes and needles of fins 

to coarse pyrite and mrcaaitr fam a glittery "dust" aver saddle 

dolomite surfaces in open vugs (P1. 6.5~). No geochemical data have 

been gathered on these mlphides. Althwgh widespread throughour the 

nine srw, there imn Gulphides are p3rtisularly c-n along late 

faults over stratigraphic thicknesses of 5 to 40 metres. This distribu- 

tion implles that the crystals precipitated fro. fluids migrating along 

late faults or relate to redox fronts aio:~ faults. 

Hamtite has a similar distribution. It c-nly stains doloatone 

hds underneath and outside sulphidss eest of the 0 end F Zones (Fig. 

1.4). It also oscurs along late faults in all areas.

Petrwra~h,hp and Distribution - Euhedral ntcgacrystais of salellile 

gypsum, barite and celestite ovemrw saddle dolomites in !ergc uugs. 

Gypsum locally cementa prsr in pseudobreccia an8 rock-mtrix breccia. 

These aulpllatss are mmmn along northeast-trendlng faults and the 

intersection of ore zones with north-trending cross-faults. 

Geosheaiatrr - Sulphates have both heavy and light 6'"s veiues 

(Appendix 0; Coron, 1982). Barite, celsstite and some gypsum have 

highly posfiivr values, 26 to 30.6 o/oo, which appraxiwte thass oE 

Ordovician sea water sulphats (Claw1 st 31.. 1980). Othor cenents 

and euhedral orystals of selenite gypsum have lon positive values of 9.8 

to 10.5 0100. 

-- Evidence of - Selenite overgmvs saddle dolomite ad mar- 

caslte. Relationships to late sulphides are unknown. Occurrences along 

faults suggest that the ecyrtals precipitated fro. fluids migrating 

along these structures. 

Intemretation - Sulphates crystallized in wgs peripheral to 

faults after precipitation of saddle dolomite and late m-asits. Hesv 

C's values inply that mst crystals fomd from saturated formational 

brule8 which experienced minor fraotionation. S- gypam, however, 

precipitated f m sulphur sources that experienced nigniflcent frsc- 

tionation by, for example, oxidation of sulphides or mldatlon of H,8

along faults by netcoric waters. 

6.14 Disntssirm of Pluid Inclusion Data 

General conclusions concerning fluid inclusion data fmm both 

carbonates and sulphides are reparted In section 5.11. Five specific 

characteristics of sphalerite inclusions are discussed hers. 

(1) riuida mntain an mixture of unknown ploportions of CrCI,, 

Nacl and probably HgCl, end Kcl. Most fluid eutectic trnpersturos range 

frm -60°C to -4l"C and a few lower salinity inclusions in ssddla 

dolonits have s T. of -33°C to -3b"C. Luck of halite drughi-. ~~anerals 

in the tluids imply that they am underraturated in necl. 

(2) Final mlting tmeretures of sphalerite and ore stage 

doldte rwe between -2Z"C end -28°C which connote salinities of 22 to 

25 eqival~nt wight % NaC1. & few inclusions nelt at -30 to -33°C 

and -12 to -15'T. 

(3) Homqenizetion tewsraturas of sphalerites range widely 

between 90'T and 180°C. The mde of T, neasur-nts for ell sulphide 

inclvsionr ia indefinite, hut the man is 140°C. The limited survey of 

the paragenetie sequence shows an extreme variation in rodal T,, Fma 

17S'C in early yellow crystals to 115°C in late ucllw-black rphalcrite. 

(4) 

Amng early yellow aphalerites, samples with high 

hmoenization tmperaturer of 170°C c m fmn passiblc "hot spots" in 

the B and H mnas where stratigraphically deep ore is associated with 

deep fracture system (Chapter 12). In contrast, samples fro. Lhe K and 

L zones have hmqsnization tempeeatura nadea of 140°C. Wre wtensive

mmpling across tho nine urea is needed to Lest for Lheri~l asomnlicc 

and "hot spot" potential. 

(5) Two possible types of hydrocarbon incluciions arc I I ) isLcr- 

connected nctuorks of secondary black Lo dark blown "ingl" phase 

inclusions (Pi. 6.3c), and (2) light b mm, tuo phase inclusions in 

which dark vapor bubbles with a high refractive index do not hmgcuize 

when heated above 300°C. Although methane inclusion8 arc comn ill nW 

deposits (Rwdder, 1984), the mporition of the ones hero are unknawn. 

Recent studies have found abundant CO, inclusions in othcr n n deposlts 

(nod nandell. 1987, personal cmunication; unpvblished USGS atudiea). 

Interpretation - Fluids trapped by inclusions at Newfoundland Zinc 

nines ere typical of other HVT deposits. raCi,-baaring brines with a 

relatively high salinity of greater than 24 equivalent weight % NaC1 

were trapped at a fnoderately hot temperature range of 90°C to 185°C and 

at Th mder of llSDC to 140°C for the various crystal stages. Burial to 

depths of 2 to 4 ka, as suggested by canodont alteration indicss 01 2 to 

2.5. m l d require pressure rorrestion to even higher hmgeniration 

tenwrstures. sme hydrocarbons such es CH. and pvssible CO, usre 

probably contained. Fluid densities were greater than one. mslly 

around 1.10e. 

Relative varletion of h-enizatlon temperaturea and saiinllics 

m y lend insight into the composition and variety of fluids in the 

subsurface (Fig. 5.8). In systems of tuo or more mired fluids m ny 

inclusions are considered hybrid mixtures of several original brines 

(e.9. Lindblom, 1986). The majority of m ntqrery sphalerites and 

saddle dolomite inclusions which have similar salinities I23 La 25 w t 'r 

:?;.I

I 

NBCI) and a bmsd T,. rsnqe (7YC to 105°C). probably cl~ysLallieed rrni 

ono hybrid or single fluid. 'The total array ot dote from cnlciLo~, 

saddle dolomites end sphelerites dlsplay a wide variation along an 

irlverse trend of hiah T..lderate salinity to 10% '?,,/high salinity 

inclusions and c fw dolmite inclusions whish represent a third mdo 

a~ili 

l w T./derate salinity. These variable cu~oritions swle either an 

evolving fluid throvgh time andlor two or mre fluids before nixing. 

each of which had variable salinities and densities. Thcsc variations 

are not adequately eqlained by single fluid modela. Similar con- 

cluianr were made Ira avch lamer data sets by Taylor et ol., (19831 

and bindblon (1906) in sbiler settings. 

S- mixed fluid mdela propose sonbination highly saline metei- 

rich flulds with low salinlty "meteoric" waters 1e.g.. llall and fried- 

man, 1963; Taylor at ai., 1983; Lindblm, 1986). salinities or inclu- 

sions at Newfoundland Zinc Uinea, particularly of pra-ore and post-ore 

calcites, ere greater than 20 equivalent weight 't NaCl. These hyper- 

saline bnnes suggest no meteoric dilution. Plots of DIH end 6"o 

isotopic composition of inclusions could better eveiuete meteoric 

influence. 

Introduction - Similar to other HVT deposits, sulphur isotope 

ratios are Pritive and slightly depleted (1 to 10 olao) relative to sea 

I Mater sulphate of the host raks I20 o/m 6"s) (Cleypwl et al., 1980). 

I 

Main ore stege whalerites vary frm 21.5 olm to 18 o/m (Fig. 6.1).

Ute red sphelerite is "aiatively depleted at lU.n o/ua (Coron. 1982). 

Ldte qalanes form two gmups at 19 to 22 ojm and 15 o/oa. LaL. 

sulphates separate into three gmups: 11) enriched qypsum wit11 21.9 

0100 and 30.6 olon (Comn, 1982); 12) barite end eelcstile riLh rerpcc- 

tlve 26.2 olm and 28.2 olm close to Ordovician sea water sulphate; and 

(31 depleted qvpsm vith 9.8 0100 to 10.5 olm. 

Ore Stage Sphalerite - Ore stage rphalerite 6"s values progre3- 

Sively decrease through the paragenetis requencc, but individual 

substages have bmad ranger of 3 to 6 o/oo and successive crystal layers 

fluctuate in cawosition (Plq. 6.1). Early tan brwn end red sphalsr- 

Ites are only slightly depleted relative to the 27 to 28 ojm ol 

Ordwiclan sea water sulphate. Bath red and yellov sphslerltsa ranqe 

widely aver 3 to 6 per mil, 22 to 19 olm and 25.9 to 20.4 e/w respec- 

tively. F m one exqle, s bmun sphalerits band with 25.9 olm 1s 

snriched 5 per lnll reletive to preceding yellow crystals with 21 olm. 

svlphur iactopes of late avlphidea are, likewise. variable. 

Isatope ratios of yellm-bmwn and yellar-blnok crystals range from 24.5 

0/m to 19.9 01-, and 22.4 o/oo to 18.4 olm respectivaly. LeLe 

olystals of individual s-~F= are depleted 1 to 2 per mil relative to 

earlier ones. In both sryrtal stages, 6"s vvl- tend to be depleted 4 

to 5 per mil laterally away from fracture me=. 

Post-Ore Sullrhides - Galena. and late red spha1erites, vhi~h p t - 

date saddle dolomite, fall into three isotopic gmupa: (I) gaienus with 

early red rphalerite vith 22 olm to 19 0100 are only 1 to 3 per mil 

lighter than the sphaleriten; (2) galnaas vith a asparate sigrrturo of 

15.5 olm to 14 olm with 8 to 12 per mil depletion reletive to as- 

'i!,

cociated ruiphides; and (3) late rod spllaierite at 10.8 olw. 'rhc 

sourcefs) or sulphur were depleted relative to the orc stngc, rxeepl 

where galenas replaced sphalriter and incorprstod their sulphur. 

Sul~hide Pairs- 'fie only possible cagenetis slllphid~ pairs Irom 

petrographic evidence are early pyrite and sphalerite. Pyrite ia 3.5 to 

4.2 per mii lighter than cogenetis sphalerite pairs. Cagenetic pyrite. 

h-er, rhovld be heavicr then its spheierite pair according to the 

relative strength of the netal-sulphur bonds (&chinski, 1969). '~hup 

the early pyrite end sphalerite are either (Ilnot cogenetic and proelpi- 

Lated in two different stages or 12) cogenetis but not in eqriiibrium. 

The vccurrencc of interlayered sulphides hvpporrs the later hylnrhesia. 

wllenas 1 to 3 p r mil lighter than early red apheierit~ pairs ere 

determined to be much youwr on petrographic evidence (section 6.10). 

If e cogenetic origin or similarity of conditions of precipitation is 

assumed, calculations frm equations for equilibrilui fractionation 

lohmoto and Rye, 1979) W ly high tqeraturss of crystallization around 

216°C or greater. Such a temperature is 30°C vamr than knam T,,'s of 

fluid inclusions. 

Intemretatlon- The sulphur of Nsv€oundiand Zinc suiphides and 

suiphstes, similar to other llYT depoaitr, is derived fm basinai, in 

th:., Ease, cinnbra-Ordovician sea water sulphate with 31 0100 to 27 olaa 

B".S (e.9. Clami et. ai., 1980). The pasltive B"'S values of the 

suiphldes range fran 21.5 o/w to 10.8 0100, or 0 oloa to 17 olm less 

than Ordovician sea water alphate. Both early ten-bmwn rphalerite and 

barite preserve unfrsctionated sulphur. In the fonnatian of H,S and 

x!:,

crystallization of sulphides sulphur fractlanated by one or mare at 

?.ill 

several processes: (1) by depletion of 6'*S according ts rile ii~cmasing 

l'atio of ~:'/5S of a hydrothemel Iiuid; (2) by kinetic aIlertc, Lo., 

nare rapid reaction rates for light isotope species; (I) hy Inorganic 

sulphrte reduction to "light" H,S which is anhar~ced in Lhe presence of 

His and organic cwounds; (4) by bacterial reauction of suiphatc bclw 

50°C; and (5) by concentration of "*S in fluids as clay-rich seainen18 

absorb "'S (Ohmto and Rye, 1979). Practionation was zest likely 

effected by inoqanio sulphata reduslion end kinetics because knan 

homogenization temperatures place reactions in the 9W'C to ~80°C range 

(Ohmto and ye, 1979; ~obinson, 1980). These reactions generated 

avlphides enriched in ."S and depleted in "6 relative to sea water 

aulphate. 

Post-ore sulphates fractionated according to relative insalubility 

of minerals and by the reduction and oxidation of fluids. Bari:e is 

~elatively inoaluble in water end tends to precipitate rapidly prior to 

significant fractionation (Sangsbr, 1976). Bsrrte should provide e 

true sample of the Isotopic canposition of the fomtional fluids. In 

contrast. the lnre solubls, isotopically heavy. gypsum is a later 

precipitate fro. waters which wets enriched in 3's as kinctics of 

sulfate reduction wncentrated "'S in H.S, suiphideh and clay residues. 

Such ohanges occur within closed fluid systems vhers crystallizetion 

selestlvely and rapidly remws "'s. (TMs and Monster, 1465: ohnata 

and Rye, 1979). 

Isotopically light gypsum fm. pseudobreccia vugs and cement of 

mck-mtrix breccie pmbahly amired its sulphur by oxidation of 1,s or

~redminanee of SO, over H,s. Near surface oxidation of li,S Iormr an 

isoto~icelly light "fresh water" suiphate (Robinson, 1980). his 

crystallizetion may have been oonteworary with hr*natita oxidation and 

migration d freah oxidized waters along Late faulLs. Liqhl and heavy 

gypsum is indistinguisheble in the Iield and petrqrophicaliy. 'Pile tw 

types my have been contqorary end oxidizing vatera along faults 

caused 105.1 oxidation. 

6.16 Siymifi-ee of Lead Iwtopes 

Lead isotope date and their interpretation have been presented in 

section 6.11. In general. the lead isotopsr give essential inlomation 

on Potential sources of lnetais end mnfigurationn of fluid transport 

SYStm8, Which my be sunnarized in three points. 

95q 

(1) The pronounced non-radiogenic, thurogeoic c~wpo~wpoition of the 

galena iwlie. major contribution of lead fmm the high grade mtmr- 

phis basement, where fluids resided, leached nstals. and subsequently 

circulated thmugh the sedimentary pile. Fluids and their cements In 

basins elsewhere contain g-hmical sigmtures, 0.9.. imtmper of DjH, 

Sr and Pb, which suggest or dwonstrate that basinal brines circulated 

tltmugh the baseiaent and egvilibrcted with it (Heyl et al.. 1974; soley 

et al., 1981; Kelly et al., 1986; norm et al., 1986). 

(2) 

The linear array of lead isotope date on compositionalplots 

(Pig. 6.6) shows that deposits at various stratigraphic levels *ere 

intsrreleted by one hydrolqic system in which fluids with "basement 

lead" acounulated increasing ymsntititss of rediqenic lead as they rose

thtough the sedimentary pile (~uinden et al.. 1908). Thrr fluid could 

lbave leached lead from the redlmentary pile andlor !nixed with L'olm,lion- 

a1 Fluids bearing rad!.ogeolc lead. 

(3) 

"611 

variable mixing ot "on-radiqenlc "basemnl" and radiqcnlc 

9"sedimentary't lead generated a range of cmposit~ons at each rlrsll- 

graphic level. I\ heterogeneous network of vertical and horironlal 

fractured aquifers probably accounted Tor inhmqcnmua mlxmg of leads. 

6.17 6- of the Paragenasis of the alphide8 and Sulphatea 

spheleriter ~rystallired in two general sequence8 identified as 

Early and Late Sulphides. Major fracturing presedd Dth sequences. 

Dissolution, which generated extenaivo porosity prior lo suiphide 

deposition, continued throughout the process. Lr early sulphidc bodies 

precipitated, rsmltlns acids or undersaturated fluids portly dissolved 

mrrounding dolostones. Later sphaleriter precipitated in these 

secondary pares. 

early sulphides crystallized in four distinctive phercs: (11 

initial srystalllzatlon oE fins pyrite In gray dolostones; (2) rapid 

presipitetion of PLS heavy and iron-rich red sphalerite and msettea of 

fibmus ten brown crystals; 1.) precipitation at varying rates ot 

millimtre-thick fibrous crystal layers f rm repealed fluid pulses; and 

laslly (4) slo* centation in wids of palisades or coarse pr~ronatlc 

yellaw crystals. Throughovt the sequence 6"s va!ues decreased. In 

detail, however, d aS fluctvated in successive crystal lminstiona as 

deqraes of sulphur fractionation in the source I?) varied with each

lr~flux of metal-bearing fluid. Variations in homogan~zation tempera- 

tare6 of yellow sphelerites across the mirm area suggcst. that certain 

""1 

zones, such as the B and H, reached higher tamperotures 01 16s' Lo IHST 

(Fig. 6.3). 

In certain respects, the transition betvaen early and i.lLe ore- 

stage sphphaleritor was e continuum. ,ilow and yellow-bmm sphalcritcs 

precipitated f m fluids of similar tmperature and sslinity. Early and 

late sulphidas contained o continuour array of sulphur Isotope -081- 

tions between 2s o/w and 18.4 0100 and ranges of 6'"s or crystal stagar 

overlapped signifiaantly. Only the lnean value of 6"s of each crystal 

stage was depleted pmgrerrively. Fractures and brecslar, howwer, cut 

early lulphides and vnrr cmnted by late ones (Pl.b.!f) (see chapter 

12). 

Ute ole-stage sphaleritea dlifered from their predecessors in 

several ways: (1) a general lack of fibrous crystals and miiiinctrs 

lminationa in cents; (21 enrichment in cahium; and (3) 6 to 10 per 

mil depletion of 6'"s relative to tan-bmn spheleritee. The cryatel- 

liretion of late rphalerites occurea in two phases: (1) Yellow-brown 

sphalerite leclested at a mderste rate as fine Lo coarse crystals 

within dolostones end along vein and pore walls. (2) Yellow-black 

sphalsrits then precipitated slowly as coarse, prlsnstio crystals from 

cwling fluids (decrease in the T,, f m 135°C :a 115°C) as ".S Mas 

depleted In the rwrce. The crystallization of the generally yellow 

crystals wae punctuated by growth zones with dark [hydrocarbm-rich?) 

Inp~rities. mew sactor zones s cmletsd during t-wry periods of 

rapid cry~tel growth (Hollister, 1910: Wvty, 1916). In general, the

cd 0: mineralization in both early and late rulphide sequences uas 

merked by cryatelliaatian of coarss prismatic cements in pores. 

LC2 

Hercasite, -rse galena and suhedral red sphaleriter srystallizcd 

in vugs and cavities along vith sulphetes after post-ore saddle dola- 

nitea. Inass late crystals uiLh dapletad 6"s precipi:.rLrd I1.m 11,s 

vith a high '"S/"s ratio, which could have resulted Irm (I) Loibg ten 

dccv~~lation of H."S relative to 8,:"s due to reaction kinctlza, asdjor 

(2) depletion of fluid '9 during oxidation and sulphate crystailiza- 

t1on. 

Lead isotopes give 9- clues to the source of metals etld con- 

figuration of psthvays of metal-bearing fluids. Fluids with the 8'"s 

seawater signature of tha Lwsr Paleozoic swiiments !nigrsl.ed into thc 

basement or overlying arkoms where they leached high thorogsnic, law 

uranogenic isad Irm feldspars of the high grad* mstmrphlc Lerrans. 

Thess fluids rocirculotad up section and In the proselin rzquimd 

radiogenic lead from leach4 sedimnts endlor fomtion fluids. The 

ridng fluids deposited leads which linearly increase in rildiogeriic 

content vith greater stratigraphic height (Swinden et si., 19BS).

INTBWUCI'ICW TO PART TY 

Part IV describes the ccmpaitian. q-try, oriqis and rrlintive 

time of formation of the various dolostones md breecias Llrt pre-date 

the epigenetic doimites and suiphides. We rock bodics thot charac- 

terize the early dolostones and brecoies ere separated into three min 

groups: (1) micmrystallins "syngenetic" doiostones; (2) mck-mtrlx 

breccia*; and 13) early burial dolostones (Fig. 1.1). Figure 1.6 

displays tbrir relative timing. Nicmryrtaiiins doiosto!~es Corn the 

extensive, 8:ratabound peritidal beds typical of the Aquathuna Fornu- 

tlon. They developed near the sueface prior to incorporetlon into 

conq~m~rates and karst brecciar. Rock-mtr~ breccia. originated 

during subsurface karstifination when caves Eomd along growth faults 

metres to more then 200 m below the surface. The ceystallizrtion or 

early burial doiostones spanned the time of prwresrive burial and 

initietion of presswe solutim when doimite nusieii eccleted zoned 

rim. This process swieted dolmitiaation of nicrocqstaliina bods, 

converted mck-matrix brecciar into dolostone bodies and Cared rattles 

and beds in iinerto!i~ favations (Cetoche and Table Point). Thla 

frmework of sesied, brittle dolortone bodies constrained the later 

psition and development of epiganetic doiostones and sulphides. Thc 

terminology used in thi- description is compared and related to the 

cleesificatia of Haywick (1984) in Teble 7.1.

A ~1088-~.~0ti0n aembs the L Zone ore body end the Trout 

I.ake mck-matru breccia illustrates the canfigvration of ths various 

dolostone bodies that comprlse the dolostone mmlans of the upper St. 

George GmUp. (1) Early fins dolostones are stratigraphic bodies 

forming mst of the Awathuna Yometion. (2) Pine mcit-matrix brwclaa 

ark Lath localized stratebound end discordant forms. Em11 bvriel 

dolostones consist of (a) a medium crystalline overprint of the fine 

doloatones and breccia%, (b) ubiquitous mttles nnd beds in the lh- 

stone formations and (0) bcdies of discordant Mostones (3) along 

fraftum zones and margins a€ rmk-matrix breccies. migenetic &lo- 

stone bodies include stretabund pseudobrecciea (I) ud coarse sparry 

dolastones (5) and dismrdant, late fault-related dolostones (6).

A 

CR-8-SECllON OF DOLOSTONE BODIES

COMPARISON OF DOLOMrrE AND DOLOSTONE TYPES WITH CLASSIFICATION OF HAYWICK (1984) 

WLOSTDNE CUSSIFICATION 

WAYWICK. 1981 DlSTRlBMON DOLOMITE TYPE. ML SNDY DOLOSTONE TYPES, MB 

STUDY 

I. WLOULOINITEG VERY RNE CRYSTALLWE: 1 lUl0 MMDR 11. 111 EARLY RNE DOLOSTCUE 

IIOUATHUNA FORMATION 

2. MATRIX OOUMOITE DISSEMINATED TO II 

EAALY BURIAL DOLOSTONE - 

CLUSTERED CRYSTALS IN 

ONLY DOLOMITE NUCLEI1 IN 

LIMESTONES 

LIMESTONE 

S. MOmE DOLDMlTE MORLES IN LIMESTONES I1 AM) 111 EARLY BURlU DOCOSTONE - 

SELECTIVE REPLACE- OF 

BURROWS, MlCRmC M017LES 

1. PERVASIVE A 

WLOSTONE 

FlNE CRm/\LLNE 

I. 11. Ill EARLY RNE DOLOSTONE OR 

DOLOSTONE SELECTlVELY 

LATER BUAlAL DOLOSTONE 

REPLACES MUDSTONE AND 1, la 

BEDS IN LlMESTONES OR 

WACKESTONE BEDS 

CO&RSEOOLOSiDNES 

5. PERVASIVE B COARSE MATRIX DOLMDNE 

IV 

DOLOSTONE 

OR 

COARSESPARRYOOLOSTONE V 

B. CAVi,Y+lLLWO VERY FlNE c?OLCSlONE IN 

CAVITIES IN A AND B 

DOLOSTONES (RARE) 

7. SADDLE DMOMm PSEUDOBRECCY. SPAR 

BRECCIA VEINS 

11011 - V 

VI. "I, 

PRWRE AND PaST.ORE 

EPlGENETlC DOLOSTONES 

REPLACE LIME GRAINSTON" 

WACKESTONE MATRIX 

EOVIVALENT m EPIGENrnC 

GEOPEIAL WLOMITES 

(GENERALLY COARSE 

CRYSTkLLINEI 

POST-RE EPBENETIC 

DOLOSTONE FILLS PORES 

AND REPLACES PRECURSOR 

DOLOSTONES 

A, 

m

7.1 lntmdostiw 

mis chapter describes and interprets dolostons bodies ~ o m d at 

or near the surface (Fig. 1.6). msse include (1) the microorystallina 

doloatones characteristic of hypersaline legaon and tidal flat settings 

and (2) Ilolmitizsd mek-matrix breccias associated with subsurface 

karst. 

7.2 Bmly Fine Dolostone 

Early fine or Syngenetic dolostones, cwrissd of microcryatalline 

Dolomite I with enriohed I 'b, selectively replace mudstone beds in the 

Ilguathune and uppsr Catache Fomtions. 'Ehe cryatal characteristics arc 

dssoribed in chapter 5, restion 5.3. The auhedral crystals raplace end 

overprint peloids and other prhary textures end structures. These 

dolanltisod mudstones include beds of supratidal dololiupinite to sub- 

tidal, massive or burmrrcd mudstones and comprise the mud matrix of some 

subsurface mekmatrix breecias. This type of dulostons mken up mst 

of the npathuna mation, and occurs aa distinct 0.5 to 1 rn thick beds 

bctween otherwise grainy linastones in the upper Cstoche Formtion. 

These stratigraphic dolostones ere mre pervasive along the northwest 

mast of Newfoundland than to the south and wst IHayvisk, 1984). 

A variety of features, discussed in Chaptsr 5, demnstrate that 

the dolostones fomd at or near the surface. The mt imprtent 

criteria are the occurrence of the doloatones as intraslasts directly

170 

above the St. George Uncontomity and their incorporation in rack-malrix 

braosies. 

IntemnrMion - syngenetic dolomites generally crystallized at or 

just beneath the surface as indicated by fragments incorporatad in 

intrafonationel ronglmrates and rock-trSn brsccias. The dolmiti- 

zatian extensively affected supretidal huathuna Iithologies similar to 

sabkhas (cf. Patterson. 19721, but also extended into subtidal loud- 

stones, subsurface rack-matrix breccia. and along faults to depths of 

2DW. The replac-nt natvre of the ryngenetic dolostones is unlike 

dolostones beneath Newene sabkhas which are composed of presipitated 

microdolmites (Yon der Borch end Jones. 1976; Petterron end Kin-". 

1982). Present models for similar replacement dolostones suggest long 

ten alteration (1 10- yr?) in the near-surface plattornl under the 

influence of atable gmund water-flaw system (Sass and Katz, 1982; 

Smr, 1984; Hachal end muntjoy, 1986; Hardie, 1987). Northeast- 

trendlng fracture system and a regionally elevated platform probably 

contmlled the distribution and navenent of these dolomitiring fluids. 

Rl~poration on the elevated platfom probably accolmted for the 

extensive supretidal aolostones and the enriched B'"0 value. of the 

dolomites. Utsmstivoly, kinetic and equilibriw effects caused '"0 

concantration in dolmites (Clayton et el., 1968). The gansral absence 

of dolomites in peritidel deposits of the Spring Inlet n&r suggests 

that avaporstion an llguathuna flats played en Wrtant role in dolornit- 

izatim by increasing W/Ca and m,jca ratios in hypersallns ground 

waters. Sea wetcr (and meteoric water?) oirsvlating beneath the

platfm along regional fractures probably caused replacencnt dolwiti- 

eation over extended tim periods (Sass and Katz, 1982; ~ein and and, 

27 1 

1983; sinnns, 1984; Hardie. 19871. It the time of the unconfumlty fresh 

Nater dilution of sea water also covld have caused dolmltization an it 

increased MglUl end m, ratios (Land, 1983). 

7.3.1 Defiaii3m1 

The tern "fine rockwtrix breccia" is defined and applied to 

brec~las of the Iaver Ordovician Knm Group of wt and Central Ten- 

~~SSBB, which POSS~SS fragmntl of angular, micmcryrtalline dolostone 

and chert in a matrix of finely crystalline. sray to gresn to red 

dolate and minor silica end clay minel'alr (Kendall. 1960; H~agland et 

al., 1965; Kyle, 1976, 1983). Mussman and Head (19861 refer to these 

bodies as intraf-tional breccias. It Daniel's Harbour, slnilar 

breccias with andax framnts of early fine dolostone have an altered 

matrix of euhedral, very tine- to medium-sised crystals of mlmitos I, 

11 and 111. The brecoies (Pigs. 4.6, 7.1, 7.2) occur lmvily in the St. 

George Group and laremst Table Point Pannetion in hdies of varying 

shapes: (I) large atratabound -1-s within the upper Catcche 

Formation which are circular to 0-1 in outline and extend up to 400 rn 

in width by lODO m in length (Pig. 1.4); (2) dismrdent, linear badies 

which 0- within the stratahnd -1uer and penetrate vertically 

core than 2DD m (Pigs. 4.6, 7.1, 7.2); (3) mall atratabound tndies. 

tens of metres in diameter that occur outside the laqe smlexes; and

Qiqura 7.2 Dlatribution of the five breccia types acmsa an ore zone, e 

large c-ite ruck-matrix breccia and a chimney breccia. 

Intrentratal rwk-mabix brecsias (Bx 1) wsur extensively 

In the Agusthuna Porntion. 

lacal cormsite bodies of rock-matrix breccia include 

stratabound oligomict bodies (Bx 2) in the upper catochn Foxmation end 

discordant polmict baaies IBx 3) along faults. These ccnplens a* 

characterized by stratigraphic collapss of the upper St. Gaorgs Orwp 

and sediloent-filled dolines dercribsd in Chapter 1. 

Chimney bresoias outside major bodies enhibit minor collapse 

end affect the lower Table Point Pornation. 

Spar brecciea IBx 4) and pseudobreceiaa (Bx 5) with saddle 

dolomite occur in the uppar Otoche mmtion pripheral to the rock- 

matrix breccies.

(4) dislinctive ahiansy breccias that cut both the $upper sl. George 

Gmup and the iwer Table Fomt Formation (~igs. 7.1, 7.:). 

Several lines of avidencs suggest that nort of the fine mk- 

maLrix breccia$ at Daniel's Hsrbwr are related to dibaolution and 

deformtion of strata below the contemporanmi; St. George Unmnfomity. 

(1) The bmcie bodies are situated below fsulted dspressions and 

dolines (sinkholes) which have been filled and levelled by the middle 

and upper mmhrs of the Wuathuns Formation as described in Chapler 4 

(Figs. 4.1, 4.6). me rewnition or the stratigraphy conrrrains the 

71.1 

dcvelopnt of the bre~ciar.(2l neasumnts of stratigraphic tl~iskness 

bet~ssn the "wm" and chert marker beds in the Catochc Formation 

indicate that brecciated strata have been thinned to one-third of 

original thickmesh (Fig. 7.3). (31 This stratigraplric thinning is 

restricted to ihestone beds in the cpper catoohe mrmtren. ~hin 

arglile~~~~s residues and mncentratcd silica nodules are the remsnts 

of these partially or totally disaalved beds (Fig. 7.3; PI. 7.1). (0 

Peagoants of the Lwthuna Formation are d~splaced up to 120 a below 

noml stratigrephis position (Fig. 7.3). (5) lud-supported mbble 

breccia* fill fomr dissolution cavities in the catochs Porntion. One 

expare of the well of ons pal-ave reveals that corrosive dissolution 

pmhcsd an irregular, scalloped surfass (PI. 7.lb.d). The lack of 

dripstme or florstones suggest bat the cave was never part of an open. 

vadose network. (7) The interplay of normal faulting, fracturing and 

dis~~l~tion is apparent frm their spatiel relationship, displaced 

breccia stratigraphy, linear and graben gastry of stluctural depress- 

ions and abundant collapse-breccia infilling d cavern systems along

Figure 7.3 A pmEile of flne rock-mtdx brescias that shows the 

geometry of the variove types of rock-matrix breccia bodies reconstme- 

tad fm drill caro. ?he cress-section between drill holes is schema- 

tic. The looation of the drill holes is ahwn an the map on the lower 

right.

Plate 7.1 Underground lvposurss of a Poly,tict Rock-mtrh Breccia 

The lower portion of a chirney breccia was cmss-cut by an 

underground drift in the T Zone (Fig. 1.4). The g m t q of this 

breccia body is raconstructed in Figure 7.3 f m a central drill hole 

and !horizontal vndergrwnd workings. 

as. A polymict breccia in the centre of the hdy fills a fomr cavity 

where Catoche limbtone was remved. Light gray fragments (5 to 20 rm 

in dimeter) of the llgvathuns Fornation and msdim-gray blooks (20 to 

100 cn in diameter) of early fine EEitoohe dolostone, are surmunded by 

grey rock matrix and by gypam-cemented fractures. The field h k is 7.0 

an long. 

bed. Pseudobrffoia beds on the right in abrupt -"tact with a rock- 

matrix breccia on the left. Rn early fine dolostone bed collapses in 

the breccia where dissolution of f m r limestone beds has left only 

thin, laminated beds of shale. These shales also fill steep extensional 

fractures which dip outward fm the brecsia. The field Dok is 20 om 

long.

fault zones (Figs. 4.6, 6.7, 1.3). 

7.3.2. Parography of Fine RocL-UatrLx Breccia* 

Pine rock matrix breccies am c~iexos of multiple dolomite 

gensrationa: (;) Oolmite I occurs in =lasts of pw-karat, fine 

dolostone; (2) Dolonitel I1 and 111 occur in early dolomitized matrix 

and olests; end (3) clear Doionite 111 is ubiaitous as remndary 

overrJra*rha, replac~~-nt crystals and pore ownts (PIS. 5.4s. 7.2d). 

278 

In addition, epiganetic dolmites IV end V partly replaoe the fringes oE 

breccia bodies. The breccia cwlexes can be subdivided into several 

generations based on the follwing cherasterietics: (1) the oligmictic 

or polmictis cmmaition of slast lithologies; (2) crystal size and 

tVpe of dolmlte(6) that replace matrix and clastr; (3) the abundance of 

intercrystalline, insolvble residues and stylolites; and (4) the 

relationships of breccia bodies to stratigraphy and structure. 

The fine roel-matrix breccias can be classified into two garreral 

litholqical twr, flne-crystalline polmist brecclss end mdlw 

crystalline oligmtst breecias (Fig. 7.2, P1. 7.2). 

Typical polmict bnccii. contain egular fraglnente of four ts 

five lithologies of very finely crystalline, pre-karst dolostone, finely 

crystalline secondary dolostone and ohert. Where the rock is e brescia 

of Xguathuna framents assenbled in a maais of =lasts that show 

disruption, its swosition my he oligmlot or mnanict. Pragnerrt size 

vsries f m I m to 2 m dimter, but is mmmnly bimodal with 1 cm ta 1 

n diameter fragments surrounded by 1 to 5 m clarta end mtrh (PI. 

7.2b.c.g.h). The abundance of matrh varies within and betmen breccia

Plate 7.2 PeLragraphy of Rmk-Matrix Breccias 

a. Oligmict breccia, Catoche Formation. Hedim-orystslline clads 

end mtrix that an out by fractures filled with clear Dohite 111 and 

gypm cement (G). Stylolites (3) and black solution residu~s (R) are 

abundant. Mike Lake Breccia, DOH 66, 132 m (Fig. 1.4). Sale is 1 cn. 

b. mlynict breccia, Catoche mmation. Light-gray frewnte frm 

the mathuns Pornation (A1 are supported h a matrix of msdimcrys- 

talline (100 ym) dolmite and ndllimetra-sired dolostone frapnts. 

Nikc Lake Breccia, ODH 66, 90 D (rig. 1.4). Soale is 1 em. 

E. mlyrnict breccia, Aguathuna Formation. PI light gray, very flnely 

ctystalllne (mlmite I) matrix surrounds dark and light fmgments 

of the Aguathuna -stion. F m disoordant breocia north of the L 

, zone, undcrgnund angle hole, ODH 1003. 120 m (Fig. 7.3). Scale is I 

cm. 

d. Oligwlist b-cia, Catache Formtien. Zoned dolmite (I1 and 111) 

cryd%la whish overprint the brecsia vary in sfae fm 100 ym in 

fragments (PI to 300 ym rhde with thick, clear rims (111) that 

replace mtrix (MI. Mike W e Brwcia, rwe sample es PI. 7.2.. scale 

is 100 p.

e. Oligwict breccia. Catoshe Fomtioa. Mostly of fr-nta (I) 

that are indistinpishable frm mtrix (M) after pervasive dolmitiaa- 

tion (Mlmites 11 and 7.11). Stylolites (5) are c a n . South mrgin 

of ths Trout Lake Breccia, DDH 1236, 188m (sout of DDH 492 in Pig. 7.31. 

SF.~. = 1 ER. 

f. Wonmist breccia, Table Point Formation. Lithified parts oE 

m2 

former noduler lineatone beds which are dolanitired, broken and rotated. 

Chimney breccia sdjaaent to the North 1. Zone(Pig. 1.41, DOH 2377. 112 n. 

&ale is 1 on. 

g. 

R matrix-supported polymict breocia which contains refts of clusts 

within a debris flw fabric. Table Point Pornation. T Zone chimney 

brsccia. DDH GH-I. 100 n (Pig. 1.3). Scale is 15. 

h. 01ismi~t breccia. Table Point Porntion. Solution-aoslioped 

clarts are suppa~ted Bx a very fine dolmite wtrix with some akeletal 

frawnts (arrml. Cemented dilatant fractures in fragments. T Zone 

chimney breccia, WH GH-I, 150 m (Pig. '1.3). Scale is 1 cm.

odies, but brecciaa comnly are matrix-supported. The matrix is 

enposed of micmcrystalline to very fine (10 to 50 pm) rhmbs of non- 

luminescent Dolomite I. blue n wlomite I1 a d raned CL Uolarite 111 

with nimr interuyrtalline residues. In placcs, msdlum 150 tu 200 w) 

crystals with turbid DDlomite I1 corer and clear wiomlte Ti1 rim 

cawrise the entire matrix. In nast cases, however, vug and Iraoture 

fillings of Dolomite 111 cross-cut a finely crystalline, nolomita 1-11 

type natrix (PI. 7.2s). 

Hedim-crystelline oli-t brec-3~. in contrast, contain small 

1 to 12 m-sized, subrounded fragments which are altered. 1.ike the 

natrix, by fins- to medium-sized =-site crystals of Dolornitas I1 and 

111 (Pl. 7.2a.o). These breccias occur in only the Catoche and Table 

Point Formations. The fragments include me to four locally-derived 

lithologies: (1) dolomitired iimrtone slasts; I21 dolostone nattles; 

(31 slastr of early fins dolodone; end (4) chert. Forsign fragments 

fm the agu~guathuna Po-tion are generally absent. Zoned, euhedrel, 

dolomite rhombs overprint mat clasts and matrix end overlap their 

283 

bwndaries (PI. 7.2 d,a). Dolomites I1 and 111 fom mdiun I100 to 300 

pm) crystals with turbid cores (11) and thick clear rims (1111 in 

matrix, fractures and pores. line (50 to 100 pm) crystals which raplace 

fragments have only thin clear rims IIII) devslopsd on ferroan to bright 

n calcis corsa (11). The urlcic corer suggest an origlnel limestone 

precursoc. modant dark intercrystalline material in the matrix give6 

the breccia a dark gray to black oolour. puwtr silt content inoreases 

to 6 to 10 weight \ twwd the base of breccia bodies. where 1 to 3 nr 

thic* shale layers of black residuals on camon (Pig. 7.3). Abundant

stylolites separate fragments and patches of medim-crystalline matrix. 

Stylolites arm also nnmon in =last-supported, polyrnist brswiaa. 

The petmgraphic differences batween the tva breccia typea 

indicate diatinct origins. The medium-crystalline. oligdst breccia 

originated by partial dissolution of limst0na and mndensetion of the 

stratigraphy with minor cam Crralapnent. This pmcecs left only -11 

284 

rounded fragments in a residue-rich matrix, all of which was dolcmitired 

during burial. In mntrast, tha polynict breccia formed fmm framnts 

of early fine dolostone which collapsed into caves in the Catoche Forna- 

tion. I gravelly lmd elther filtered down between mllapaed fragnnta 

or arcunnrleted with clasts as md-sllppwtsd debris (PI. 1.29). During 

burial only the mtrlx was atered to fine- and medium- crystalline 

dolanite. Pam of the original mtrix nay have been a dolomite silt and 

md which filtered down from the surface (Knight. 1986). 

Fine mck-mtrix brecciaa (PI. 7.2) differ f m "tecLonisv fault 

zone brscciss and saddle dolomite-cemented "sparar" bresciar (Pl. 7.3; 

Teble 7.1) (Lane, 1984). Pault.one or "tsotonic" hreooisa are confined 

to narrow mps (1 to 10 w vide) that ocm st steep angles to bedding. 

They me w e d of mltiply-frastured frawnts and very fine "gran- 

ulated" fragmnts in a very finely crystalline matrix of white dalanite 

flour" (PI. 1.3b). several generations of fractures and veinlets 

cmssont bath matrix and fragnents. wr brecch vhhh omaa-out 

steatigraphy are c-nly arranged in masics of partly oollapsod to

Plnte 7.3 Other Breccia Types 

a. Fault breccia (F) showing subvertical planes, several oenthtras 

wide, offsets bedding. Nwrous saddle dolomite veins oronr-cut the 

surmunding rocks. Hest end M the T Zone (Fige. 1.4. 10.1). The 

length of the field bmk is 20 m. 

b. Mi~mbZe~eis I L a ~ fault zone. Fragments are outlined by black ink 

lines. Typical of all fault me.. Dale is 1 m. 

c. Late spar b-ia. consisting of broken dark gray dolostone beds and 

saddle dolomite cement. B-ia fabrics include iq mosaic brffsir 

tion (M) and collapsed frapnts (C). adjacent to cmss-fault in the 

I "eat L Pane. ~ h scale s is 2 m. 

d. Early t'cck-mtrix breccia showing its matrix (II) locally replaced by 

saddle dolomite. Sqle of the saddle dolmita fUls late veins (v) and 

oegaporar (P). mere L Pane intersects Tmut lake mck-matrix brsccia 

at a cmsa-fault in the nest t Zone (Figs. 1.4, 7.3). The scale is 1 I.

TABLE 7.2 

BRECCIA TYPES 

VARIETY OF FRAGMENT SHAPE AND 

m?E FRAGMENTS S(ZE CRYSTALSIZE MbIW 

Fine 

Rock-Matrix 

Oligomia 2-3 13 cm Rounded, medium Medium crynalllne 

cmalline (l1.111) ~11.11l) 

PolymiR 4-7 1 cm - 1 m Angular, very Cne Fine (I) to medium 

crystalline (I) wystalline (11. 111) 

Fault Zone 1-2 1 mml cm Angular Whiie rod( tloour 

Spar Breccia 1-2 up to 1 m Angular Megactystalline 

saWle dolomite 

Pseudobreccia 1 mm - cm Imgular, Medium to mega- 

aggladational crystalline saddle 

replacBment dolomite 

Stratabound in 

limestones 

Dismrdant. 

"Cave Filling" 

1 to 10 cm wide 

along faults 

Dismrdant, along 

veins and faults 

Stratabound over 

10oO's of metres _ 

B

2as 

nm~ollapsed, atlgular Fragments "supported" by white saddle dolmite (PI. 

1.3c,dI. The saddle dolomite in these brecoias occurs as a pars-filling 

cement between fragments. In contrast, atratahand pseudobrsccias 

contoin abundant d ite saddle dolnilte which both cencnts networks of 

solution wres and partially replaces gray blostone. The remaining 

patches of gray dolostons leavs a breccia-like fabric (PI. 5.5a). The 

aaadle and "whits rock flwr" dolmitea are younger "deepm burial 

dolomites (V and VI) conpared Lo Dolmites 1.11 end III which cmprire 

the mck-matrix brescies. The relative timing of the dolomites is 

enalyred in Chapter 5 and the t-rsl reMionnhips of dolomites end 

breccia types is graphicslly presented in Figure 1.6. 

Four types of fine rock-matrix breccia badies occur in the mine 

area (Table 7.2). h mplex histoq cf seueral -vents of bncciation 

end faulting durlng nwr-surface karstificetion generated overlapping 

relationship= between these various type (Pigs. 1.6. 7.2). 

1) Intrastmtal Breccilu - Intrastretal breach, 10 ta 30 em 

thi*, occur an r~innally extensive atratabmnd layers that represent 

disconformities in the nguethuna Formtion (bee Chapter I for details). 

By urincidence, however, they my form pert of breccia cornplexas. In 

addition, they are also loceuy ~verpdnted by collapsed dolcdtonea 

assocleted with sagging of overlying beds w e the disconlomity 

surface (~ig. 4.4). 

The breccia matrix has undergone several episdes of dolwitiza-

TABLE 7.3 

BODY TYPES OF ROCK-MATRIX BRECCIA 

BODY TYPE GEOMETRY COMPOSITION SFIATIGRAPHY INTERPRETATON 

lmmlfisl mensb nmlormalbnal mmdCt 10 mhuna Formaion: wae~read dbs3lutbn of 

bed (70-50 om lhiCI0 0UgadCt shalecongbmerae mnglamemle-evapo~e beds: 

evamrite-ho#mns unrelated to olher Miel stratabound suatamund 1-30 m tidsr: oll~mfit m upper Camdls Formatm subsidem doline csused by 

oi@m!d to to 1000 ;I?: elliptical bc.4 powm geomslrically mlaIed lo early and hcomplele 

area bodies redimenlatbn ot the middlt, dissolution 01 Ihe upper Catoche 

Aguathuna mmter orm mat ion 

oiwdm 

Polymm 

~armw (3-49 m wide): 

w lo 200 m deep: elongale 

polpa 

lnoblding bw 

abng lauk related lo 

sinkholes lilled w'W the 

muapse doh mdwd by 

cave tormaran abng laus 

abng fauna blow nab of 

emgamin 

Upper /\guathuna 

formalion 

beneath the St. George 

Unconbrmky, lollowed by 

mllapse 

cnrmey w~~ndrrcal: so-so m generally oulsupper80~oge 

dlrsohltin along fmmr B d a diameter up to 200 m deep poWi lo Gmup and the lower Tablt, formed -1 deep mes beneath 

locany pain! ~ormatbn 

Table Point planon 

oligamid

tlun. Dolomite I c~onooly forms the natrix which is locally cut by 

veinlets and pores cemented by medim-sized, cornpositc crystuls oe 

uolmites 11 and 111 (PI. 5.ld). In sne places these early burial 

dolomites replace all of the natrir. Late megaquartr locally roplacea 

these dolmiter and minor saddle dolomite mainly fllla late veins (PI. 

S.ld). 

190 

Intemmtation - Intrastratel breccia8 are the remains a€ beds of 

shale, quartz congl-rate and evaporite which acccunletsd at regional 

int~1-119~athVna dihmfomities. The beds originatad initially as 

conglomerates and brecsias at emsion surfaces (Chapter 4), but later 

shalla subsurface vatws are interpreted to have dissolved evaporltes. 

limestones andlor carbonate md mtri. cansing wedying dolostones to 

founder and partir'ly collapse into solution cavities. The presence of 

Dolmite I matrix in these breccies suggests that collapse was early, 

asarring only mtres balm the d*pnitionel surface. This nore 

pemeble mstrix war then subject to dolmitia~tion and ailioification 

several times during burial. 

2) Stratsbauld 01-t Breccia - Broad, aligdct breecias, up 

to 1 km* in areal extent, occur in the upper 10 to 64 m of the Catoshe 

Fornation (Figs. 1.4, 4.6, 7.2. 7.3). The bodlea srs oval to circular 

in plan and elongated dong northeaat-trendlng faults Wig. 1.4). The 

breocies coincide with strvstural depressions, but extend over 100 n 

beyond the -ins, where they are displaced along faults that bound the 

depressions (Fig. 4.6, 7.2). Brecsiation, in these mwinal areas, is 

omnly restricted to the upper 10 to 15 m of the Ultoche Porntion.

Tile lower nrelabsr of the Armathuna Fomtion abovs the breccios is 

fraotured in its lover 10 to 20 n but is otherwise relatively undis- 

torbed even though it settled or sagged to form structural depressions 

which were filled by the middle meher of the Aguathulla Porntion. 'rho 

211 

middle maenber gradually thickens frm 5 to 25 n over the nnrginr and 

. reaches a mh thickness of 70 mover the centres of hraccias (Figs. 

4.6, 4.7). Ths marginal faults also offset the middle &r. mall 

(20 to 30 n wide) oligmict breccias also oomr along northeast-trending 

tauits and are associated with minor or no structural collapse (Fig. 

1.4). 

oiigaoict breccia is distributed thmugh vertical sections of the 

upper Cetoshe Formation eithse a. 10 m thick uninterrupted b r ~ ~ i a 

sections or intsrcalated with 20 to 50 m thick wrly fine dolostone 

beds (Fig. 7.3). 11) these sections the upper Catache mmtion between 

he "no-" marker end chert markers has comnly been thinned up to 30 

a end eqiiiaceaus residues are the only remainder of linestone beds. 

This ergillaeeous material occurs in a mtrix of Doimitss I1 and I11 

between dolostone Eromnta, fons prminent layers at the base of 

hressia "bedsv and fills fractures in underlying limstones (Pi. 7.1: 

Fig. 7.3). 

Looally these oligmict brescias are cmss-cut by poimist brec- 

cias, 4 to 10 a thick of uokm gametry (Fig. 7.3). Mnporitio~ily 

they range from mtrir-supported breccias to upward-worsening, clast- 

supported brecsias. 

Intenwtdion - The rtratabnvld oligmict breccia* foned during 

the deposition of the middle m&r of the ~guethum Pornation when

' 

faulting, low1 subsidence and uplift began to effect the platform. 

During this time, subaurfese grounhrater flowed thmugh the Mrentic 

zone along northeast-trending fractures and into permeable, early Pine 

dolostones. These fluids probably travelled in the subsurface Irw 

distant recharge ereas in uplifted end erposed portions of Lha platform 

(sf. deep gmund-water ~mdels for the Florida Peninsula, Back and 

Hanshau, 1970; KoMt at al., 19171. These ground waters ~rtensively 

affsoted the upper Catache Fornation in closed, cirmlar to elliptical 

areas (up to 1 W) along the fracture me.. Ths waters pmbably 

297. 

migrated throughout these areas along networks of mll fractures, pores 

and intercalated dolostone beds. Partially dissolved and "condensed" 

lincstone beds collapsed into oligdct breccias of local dolostons and 

IUnestooe fraqnts and insoluble residues. This phase of subsurface 

&st pmbably resdled the immture stage of diffuse fluid mvwnt 

described by fiite (1969) and Ford (1988). The fluids aventuolly 

fooupred along fractures, where they amavated local caves vhlch filled 

with collepaed, polymict debris (sf. Darure stages of White, 1969; 

Parireit, 1976). 

one or rmre reasons account for the dissolution m the upper 

p&im of the Ilnesteae Catoche Formation. Waters probably travelled 

through dolostone beds that were abundant within end above the upper 

Catoshe Pornation. Those fluids were nrt cormsive where they eon- 

tacted and mixed wiffi near aorfsce vaters and nlxing of the fluids 

caused then to hecone undersaturated with resnspt to calcium carbonate 

(EqU, 1980; Ford, 19881. 

The broad and gradual diseolution of the upper Catmhe Wrmction

ceussd subsidence of the lower mbsr of the Rguathuna EDmation. ?ha 

293 

resultins subsidence dolines (Jennings, 1971) allwed laaal flooding and 

the deposition of the middle d e r of the Rguathuna Fomtion. he 

elliptical geometry of the dolines and their nvlrginel sag imply n karst 

rather than stmctural origin. 

(3) Dismdat mlnict 8-Lea - elonsate vertical bodies of 

polymict breccia penetrate over 400 metres of section f m the top of 

the Rguathuna to at least the base of the Cetoche Formtion (Figs. 4.6, 

7.2, 7.3). They fom along faults which cut oerliar bodies aE ollmict 

breccia and also displace the middle menbar of the Apuathuna Fomtion 

up to 50 n. The width of the bodies "arbs f m 10 to 100 metres elong 

strike and they can be treracea laterally 500 to 2000 m. The breccias are 

steepsided end o-sad entirely of framnts of wiguethuna h'omtion and 

mck matrix. They out surmvndiq 30 n-wide haloes of oligmiet breccia 

which replace Catoche limestones (Fig. 5.3). The breccia. are overlain 

unmnfomably by argillsoeous limstones of the upper &r of the 

Awethvna Fonmtion (Fig. 4.6). 

Large breccia bodies, 50 to 100 m in width, include large blocks 

of the ngethuna Formtion tens of metres in diamersr, but narrower, 

vein-like balies, 50 to 300 om wide, are Filled vith polymict clast-sup 

ported bressiaa (Fig. 1.3). Brrcis with abundant matrix occurs in the 

sheltered mains of bodies (Fig. 7.3). 

. ImmtaUoa - stratigraphic and etruotural relationship dmn- 

strate that these breoeias past-date the stratabound o limict types and 

the deposition of the middle whet and were oontmlled by faults that

displaced both the middle menher and the oligomict bodies. Initial 

faulting and incipient breccias may have been coeval with stratabound 

types,hovever. mere breeciaa rtaped upwards to the surface of the St. 

George Unconfomity they flmred collapse dolinss which ware later 

fillad by sediment of the upper Aguathuna Formation (refer to section 

4.5). Slumped beds within there deposits suggest that wllayae can- 

tinued during the deposition of the uppar menher. 

The faults which displaced the middle m d r feciliteted gmund 

wster mv-nt. Incr-in9 volumee of ground water excavated narrow 

cavities along the faults deep into the Catoche limestones as flvid 

mixing and turbulence enhanced dissolution (Thrsillkiil, 1968; !hite, 

1969; Bcgli, 1980; Pmd, 1988). Ground waters also pervaded 30 m 

29.1 

laterally into surmundi~r~ limestones to partially disintegrate the well 

r ~ and k fom haloes of oligomist breccia. 

The Rguathuna Pornation collapsed and filled the cavities either 

as large Eracturad end tilted blocks or as a plyminnict debris of small 

fragments. The natrirsupprted polymict brsccias and lack of vadose 

dripstones suggest eubaq-uuur dsposition in the phreatio zone. Pinal 

wllapse of the Aguathuna Pornation into the cams my have occurred 

during the St. George Unconfomity when supportive ground vat- drained 

fro. the cavities (might et .I., in press). This collapse along fault 

lines created linear slnkheler up to 50 m deep on the unconfomity. 

These collapse dolines were filled hy terrestrial md. and subtidal 

rhythmiter of 'he upper &er of the mathuna Porntion as subsurface 

karst and faulting probably sontlnurd.

4) Chinw B-c& - Chimney-shaped breccia. occur along frec- 

tures and faults outside the large breocie cmpleier dessribsd above. 

They ere n- and cirmiar in plan with an approximate diameter of 80 

m and penetrate mre than 150 m of section from within or below the 

Catonhe Forntion to 20 m shove the base of the Table Point Porntion. 

The chimney brecciss at thmvgh noml Aquatmna stratigraphy that has 

only thin middle and upper mmbers. These relationships suggest that 

ths development af these breccies had no effect on llguathune Porntian 

and probably post-dated deposition of the St. Gwrge Group. 

295 

The brscoiss possess an hourglass gemtry which rsflects vertical 

changes in their structure and smposition (Fig. 1.31. In the Table 

Point Fomtion, the breccia. are up to 80 rn wide and include oligdet 

brecsiaa (PI. 7.Zf.h), loc~l polmict cavity fills (PI. 7.29) end 

intercalated unbroken beds. The brecciar narro* to a 30 m width in the 

Amthuna Fornation where the stratigraphy is broken and prtially 

collapsed, but exhibits only minor evidence of dissolution. Frapnts 

of the Table Point Fornation ocm locally within this pert of the 

Setion. In the Cstoche Fornation where the badier broaden out again 

they consist of mlpict breccia3 includiw large fragments of the 

Aguathuna Porntion and broken dolostone beds of the Catoche Fomtion 

(Pl. 7.la.c; Fig. 7.3). Linescone beds are smpletsly ranvlved except 

for abundant ecc~lations of black, insolvble residues in fractures and 

stratified layers (PI. l.lb,d; Pig. 1.3). me c-sition of these 

b~oias is indistiymiehable tron earlier ones, but the abrupt save . 

walls suggest that a lithified and cemented well rock resisted disinte- 

gration to oligaaist breccia.

Internretation - The chimney breecias are interpreted to have 

296 

fomd during deposition of the Tabla Point Formation when ground waters 

migrated thrwgh the subsurface along ve~'tical fractures. 'This event 

may luwe occurred dUring an interval of reqional exposure end defoma- 

tion of the plstfom that occurs 20 rn above the ba- of the Spring Inlet 

rider (s. stenzel, pers. cm. 19881. Dissolution at intersections of 

vertioal fractures r-ed limeatones of the catoahe Porntian to for. 

cylindrical caves. The Dgvathuna Pannation fraotursd and partially 

eollapried to form polymict, rock-matrix brecoias that filled the 

underlying phreetic caves. subrurface waters entered the basal 20 m of 

the Table Point Tonnation where they l~sally dissolved limestone beds. 

7.3.5. The Riatory of Pins R&-llatrir Bmoaiu 

The m&-matrix breccias in the mine area have a conplen but well 

domentsd history that swgests they fornud by dissolution in the 

phrestio mixing m e generally close to northeast-trending faults and 

fractures. Dnnnrent with tidsl flat deposition d the middle m&r 

of the Rymathw Fomtion the plstfonn ra. disreeted by northeast- 

trending fractuee zones. Meteoric fluids (andlor 0:kr subsorface 

saline waters) infiltrated and migrated along these fractures, beme 

undersaturated vhere they mixed with near surface raters and dissolved 

lbstone beds in the upper catoche Porntion. This resulted In the 

loci1 developmnt of subsidence and mJ.lapse dolines along mrthsamt- 

trending fracture zones.

247 

Fracturing and ~ubsvrface karat occurred in five stngca (~ig.7.0: 

Stage 1 - Fracturing of the platform probably initiated during the 

deposition of the larer rider of the Aguethuna Yomation as localsub- 

nidrnce and flooding of the tidal flats occurred abave fracture zones 

(Fig. 4.11. 

stage 2 - Fractures became wsli developed during deposition of the 

middle nrdw of the Aqguathuns Fornation. At this tine meteoric waters 

migrated along frasturer, pervaded the upper Catosha Porntion along 

networks of small fraaturcr and partially dissolved and transformed 

lhstone beds into strathnd olimict breccias. Progressive 

dissolution localized fluid mvslnent through fractures end lame pores 

where local atratllbound cave* were fomsd and filled with polymict 

breooia. Dissolution of the upper Catoshe Formation in concert with 

gmwth favlte caused gradual subsidence of the I\gusthuna r-tion and 

local flwding of contenmorsnwus tidal flats of the middle menber. 

Tidal flat sedimentation kept pace with subsidence creating an anomalous 

60 to 10 m thickness of the middle ndar wer the subsurface breccies. 

Stage 3 - hlring rubaerial exposure of the Ordovician platforn, 

regional faults displaced ths middle e r and the ntrathund olignr 

ict bmcciaa and fecilitated migration of incressed volmsn of mteorio 

water. 

Stage 4 - Dissolution a€ limestones along faults to depths as 

great as 100 m excavated cavities in the Catoche Porntion. lame 

blda and polmiot fpnents from the Agusthune Fornation collapsed 

into these caves end left 50 n deep. linear sinkholes on the aukrial 

sllrfaoe of the unmneomity. A succession of terrestrial and subtidal

Yigvre 1.4 Possible chmnolagy of events during the fomtion of fine 

tock-matrix braccias. Subsurface fracturing and karst ossvrred in five 

stages which are correlated with the depocition of coeval sadinentam 

formations. 

Stage 1 - Increased rates of subsidence of the platform along fracture 

zones resulted in a thicker, nare subtihl lower lnambsr of the Aguathuna 

Fomtion rslativs to adjacent areas. 

stage 2 - stratabound dissolution of the upper Cstoshe mmtion and 

initial faulting resulted in the famtion of oligmiot bread- and 

subsidence dolinoa vhioh were gradually filled and levelled by the 

middle a dst of the Agvathuns Porntion. 

stage 3 - As teotonism continued faults displaced stratebound oligmi~t 

brecsias and the middle & of the Aguathuna Formation. 

stage 4 - At the time of the St. Gwwe Uneonfomity dissolution of 

: lhstonss along faults pmhrced deep discordant cave. vhich filled with 

polynrict brecsias. Pbmpt mllapse of the Aguatbuna Borntion pmduced 

collapse dalinea (sinWlole tmughs) which were filled by ahales and 

rhytlunites of the upper a-r. 

Stage 5 - Late nerm cbilnnay brecsiari rhioh penetrate f m the 1-r 

Table mint Formation to tha Catoche Fomtion did not affect Lguathuna 

sedimentation and probehly developad later.

EVOLUTION OF KARST BRECCIAS

300 

muds of the uppsr menbe? of the dguathuna Formation fllled the ninkholes 

during Iste stages of faulting end solution collapse. 

8-B 5 - During deposition of the Spring Inlet Member rcglonsl 

faulting and marine regression renewed neteoric elrculatian through the 

CaCoche PomtiDn. Chinnay caves formed along the intersections of 

steep fractures separste fmn earlier breeeias. Subsequently, lgvathune 

dolostmes fraotured and partially wllepsed to fill the caves with 

polynict mck-matrix breccia. This probably facilitated upverd nxlvenent 

of grouna waters into the lmr Spring Inlet Werner where Eurkhur 

dissolution and brwiation tmk place. 

In ~ncluaion, the rsgional distribution of mk-matrix breoeies 

and early fine dolostenes along northeast-trending faults of wrthuest 

Newfoundland inplies that a mnplex system of subsurfaca ground water 

novuant strongly influenced hrrtifieetion and dolomitization. 

Regional flactures served as conduits Far the flor of lnetcoric waters 

which dissolved catwhe limestones adjacent to faults and more than 280 

m below the surface. These meteoric (and/or fomtional brines) waters 

pmbebly becans undersaturated and particularly corrosive at mix- 

zones along faults ad ~tratigcsphic dolostones. Fracture conduits also 

may have enabled warm salirne waters to circulata thmgh the svbsurfaea 

and cause early &l~tizition of the mtrix of discordant b-ias and 

portions of limestone formations (of. Florida Peninsula, Kohout at al., 

1977; and the East T-8 Basin, abet, 1975).

8.1 Intmhlction 

me formatinn of early dolostone Ddiss wati completed during 

initial burial to depths greater than 30. with tha developlncnt of 

crystals of Wlmite I1 end 111, the ubiquitous cloudy-core, clear-rim 

orystals which are interpreted to have gmwn during burial (restions 

5.4. 5.5) (Pig. 1.6). This phase of dolmitization entalished tho 

dolostone framework which constrained defomtion end fluid mvenant 

during epigenetic events. Although mny crystals nucleated early during 

diagenesis, their final devslopment Dccurred concvrrently with pressure 

solution at burial depths greater than 300 m. The detailed crystel 

pstmgraphy describmd in Chapter 5 denanstrates a multistage history of 

cryatal gmwth. corroded, dull a cores of Ooldts I1 ere partially 

replaced and overgrown by pink a dolomite (P1. 5.1L;. Wlmite 111 

farms clear-rim overgmwths on sme of these crystals and pore ceinentr 

with multiple layers (Pls. 5.la; 5.4a.b). 

8.2 Distribvtim 

Bvidenee of early burial ddomitiaation is widespread in all 

formations. The widespread nsturc of theae doloatones contrasts to the 

Eault/fracturs-controlled distribution of later epigenetic dolostones. 

The dolostones composed of these dolwnites vary f rm massive doloalons 

beds to disseminated crystals in limestonas (Pig. 8.1). In the Aqua- 

thuna Porntion Oolmita I1 replaces s- laminations and mrtions of 

hrrmcd beds (Pl. 5.la). Ubiquitous cmnts of Wlomite 111 fill

~iguce 8.1 Dolostone Evolution from 

Near-sul'Eece to Burial Dalmitieation 

The illustraUon depicts the dolmitilation hismry of 

liihologiea of the upper st. Gcorge ~mup f m early on the loft to late 

on the right. Five oenthetre-scale lasgnificationr illuatrete ths 

overprinting effects of burial &Imiti2atioo. Finely crystalline 

dolostones, fine mcklnatrix breccia. and dolodone mttles within lim 

wackesbne. end packatones fomed in the near-surface with the crystal- 

lization of Dolomite I and nucleii of Dolomite 11. During early burial 

the low tern growth of Wlmiter I1 and I11 resulted in campsite 

crystals, and beds and patches of d i m srystalUn~ dolostone. The 

~.rystalliaation history of finsly crystalline beds end rosklnatrix 

breccias virtually ended after closing of pares hy mlmite 111. 

Epigenetic dolomltizatlon (Dolomites Iv, V, VI and VII) selectively 

altered limsstons beds adjacent to fraoture sptw and cemented 

fractures cutting earlier dolortone M im. DurLng the firat epigenetic 

event coarse matrix dolostone replaced linestones a d early dolostone 

mttles. ore-stage and post-ore veins and solutlon pmcs then cut pre- 

ore, coarse matrix dolostones (IV). After sulphide deposition, mega- 

crystalline saddle dolmitcs (V) filled pores and pervasively replaced 

pre-ore dolostonas to form pseudobreocias. late fault-related dolomites 

(VII) replased limestoner along the latest faults. Subsequent disrc- 

lvtion of incmpletely replaced limestone left ubiguitoua parositp.

secondary pores in these dolastones (Pl. 5.la.d.e). mpocitc crystals 

104 

OF ~lonite I1 and 111 pervasively repiace rock-mtrix breceias in both 

the Aguathuna and Catache Formetions (PIS. 5.ld; 5.la; 12.2dl. Dalmilc 

III also cements nunemus fractnres which cut ~hu brecciss (~1. 12.2a). 

The lack of later dolmites in these dolostone bodies indicates that 

wlomlte I11 ultimately sealed the rocks. 

In the Catoche Fornation Dolonitas I1 and TI1 occur as pare 

eenents (mostly 111) in finely ccystoiline dolostones (fomer mudstone 

beds) (PI. 5.le) and (most.1~ 11) replace varying portions of other 

lithologies fro. entire beds of bvrmved wackestono to smll pelehes or 

rotties and disseminated crystals in grainstones as discussed in 

~ections 5.4 and 5.4 (rig. 8.1; P1. 5.3a). Dlomite I1 replaemnt of 

bUmo~8 and compacted mud layers pre-dates calcite veinlets (PIS. 5.2~; 

5.3a). Dlomite 11 also occurs along later stylolites. cments of 

mlmite 111 along the vertical sutures of stylolites suggest that there 

crystals precipitated mnt-raneously with pressure solution. 

Dolonits 111 is c m n in dolostone beds where it csmcnts intercryr- 

tolline pores and replaces bvrmu xnolds of cosrs~ calcite. In tha 

limastonea it does not replace these calcitm mlds and its distribution 

is sporadic as pore-fillings in veinlets and around the nergins of 

patohes of Dolomite 11. 

wly burial dolomitrs (I1 and 111) also €om pervasive dolostono 

bodies in the camhe mmtion. stratabound dolostones occur exten- 

iively in the upper 10 m of the Catcche orn nation and are recognized in 

the mine stratigraphy as the OIvk Gray mlonites (section 3.2). 

Discordant bodies of dolostone iocally penetrate the entire Catoche

mnmtion. They occur in several Corns: us cylindrical or Lobular 

todies along faults or fracture zones or as envelopes around rack-mslnr 

brecsias (Pig. 8.2). 

The distribution of Dolmites 11 and 111 imply that fluids 

primarily algrated along stratigraphic dolostonca und vertical Fracture 

6yStm8. At increasing depths of burial subrurfaca fluids rewtcd with 

Dolomite I1 crystals end Pennant limneetone patches, cauaing dissolution 

and sesondary porosity. Dolomite 111 cements subsequently filled these 

psms and significantly reduced the permability. 

8.3 1ntupretatian 

The widespread distribution of these dolastones as mortlea and 

beds in all limestone fomtions end compaite additions to earlier 

dolostones 11npiy that limestone fomtions partially or completely 

dolmitized during burial as a result of pressure solution, change in 

pare fluid chemistry with burial endlor long tern exposure to 

fornational waters. Much of Lhe dolomitization was probably generated 

by waters which cir~ulated along the s m northeast-trending tracturea 

that influenced karstificstion. Dolmnite 111-cented fractures within 

?a!; 

the mk-matri. brecsias and elongate bodies of discordant dolastone are 

evidence of this later fracture-eontrolle< fluid mvment (Fig. 8.2). 

Abundant solution fsatures end Dolmite TI1 cements within stratabound, 

fine crystalline dolostonas also indicate that fluids migrated laterally 

through there beds. 

Early burial dolmitization can be amrized in four stages 

eeperatad by two events of fracturing end dissolution. This history 1%

P~(JUIE 8.2 Dlbtribation of Deep Discordant Doloetones 

Elongate patches of nedlun arystalline dalortone (black) 

penetrate the middle Catoche aonvrtlon alw northeast-trendlng fracture 

zones and €om oontinuous bodies peclpheral to mek-mtriu brscciea. 

Linear bodies of late epipnetic, coarse sparry &lostones also reflect 

dalomitiratlon along steep Eault/tractu2e zones. 

The map was prodwed frcnr e pattern of marre than 500 drill holes 

whloh penatrste the #middle Catoche mrnation.

DISTRIBUTION OF DEEP DISCORDANT DOLOSTONES

llared on detailed petrographic relationship= doscribed in aecl.ions 5.4, 

5.5 end 5.10. 

10R 

Stags I - Dolmite I1 replaced compactad muds and burrous prior to 

pressure solution. Thcse early repiocemsnt dolomites llT) cryatnllired 

from fluids in equilibrium with salsiLe and gained their turbid texture 

frm numerous inclusions and iocwlete calcite vepiacsmant. ~~.ncrully 

these crystals first appeared as disseminated nuoloii In limestones. 

stage 11 - The preceding replacive dolonitization continued during 

initial d~veloment of stylolites, but en event of fracturing end 

calcite cemntation separated Stagsa I and 11. Final stylo-inottle 

textures of euhedral dolomites displacing insoluble residues suggests 

that the cryatelo were styio-reactatas or stylo-cumlatea (PI. 5.1~) 

(wan end Sminiuk, 19761. 

stage I11 - oolmite I1 crystals becans unstable during continued 

burial as fluids corroded rims and later plnk a phase dolomite partial- 

ly replaced cores and overgrew rims (PI. 5.lb.e). This resuitsd frm 

the changes in the fluid chemistry either (1) as pmgressive buris: 

encountered mre lallne fluids at depth (Eonham, 19801 or (2) as renewed 

fracturing facilitated the introdustiion of ellochthonous fluids. The 

evidence of fractures and discordant dolmitiration support this later 

scenario. The emplacement of the Taconic Lllachthon, which abruptly 

buried the st. George Group, probably generated the fracturing. 

stage IV - zoned c-nts and o~rgmvtl?~ of mimite 111 cioaed 

pores in massive dolostone beds and mck-matrix breccia=. 4 signillcant 

change occurred in ths subnuface as dotmites began to mainly form 

cements rather than taplac-nt crystals. Dolwite I11 gradually

cnnented pores as variations in the regional fluid flow and the rate of 

preoipitation created fluctuating redox conditions resulting in s zoned 

crystal chemistry. Fluid inclusions with negative crystal lnrphology 

suggest that Stage I11 followed rignif!.cant burial of the st. w ~ y e 

Group benes1.h the Taconis Allochthon. The absence of Latcu doknnitc 

overprints in mst finely crystalline dolortones Inply that cernenta a€ 

oalmite I11 made these d:lostone= impervious to later fluids. 

309

Strnta'nd complexes of epigenetlc, caarre cryt:tillllnu dolostatlea 

and sphalerites sowrise apprarMately 75 8 of Lhc uppor 50 m or tho 

Catoche Fornation. They locally penstrate the entire fomtion as 

narmw, discordant, tabular and chinnoy-shaped dolostones. The dolos- 

mnelqhalerite (D/S) cowleuas range from 300 to 1000 m vide and 

slrrmnnd early rubvertical faults and linear system of stratabouod 

veins. These vein system enclrsla early, karst-related rock-matrix 

breccia bodies. prallel faults and occur on the flanb of gentle folds. 

These dolostone/sphalerite wlexos are offaet by late Caults related 

to the long Range Uplift. Ute stage dolostones replace limatones 

arljasent to tnese structures, forming narrow, tabular bodies that cross- 

cut the antire Catochs and Tabla Ispad aection (Plg. 7.1). 

In Part V coarse dolostone / sphalcrite caapl-s constituto Lhe 

entire epigsnetis bodiss of mck. The mck bdies consist of several 

main compon~nts. vein systems (described in Chapter IG), camposed of 

severel generations of fractures, charaoterire the cores of cvlsros. 

sulphida bodies (described in Chapter 12) generally overprint pertions 

of the vein system. Coarse dolostones envelope all these cmwnenta 

and extend well beyond the vein systems. The coarse doloatones arc made 

up of ps-ore dolostonec (described in chapter 11) and post-ore dola 

stonas (described in Chapter 13). which overprint and generally replace 

the earlier carbonates. A series of figures llllletrate these reletion- 

ships. Figure 7.1 is a 'ypical cmss-section of the dolostones and ore

zon-a. a IMP DE the sac area (Fig. 9.1) shovs the dirtrihullnn oE 

dolantone facie8 in the upper Catoche Porntion. Mundant saddle 

hlmite 040% in coarse dolostone beds) occurs locally along ore zones 

and vein systems. A map of lllr mine area (Fig. 9.2) exhibits the 

intimate relationship between linear ore aonea Md rmk-matrix hrcccias. 

The structural oontours demonstrate folding around these bodies. A11 

gener.atim8 of faults and veins closely mnEom to the distribution ol 

112 

ore zones (Fig. 9.3). Discordant dolostones are distributed along these 

structures and the boundaries of msk-matrix breccias (Figs. 8.2, 9.4). 

Petrqraphic and Eicld relationships r-nstrain the origin of 01s 

cm~Iexe8 to D period of tectonic fracturing efsr early burial dolo- 

mitization (Dlmites 11 and Ill) and pr-eding folding and Euuiting 

assosiatsd with the uplift of the Long Range Inlier Iptmgraphic evi- 

dence discussed in sections 5.6 thmugh 5.10). The tbml maturation 

of conadonts la1 2 - 2 112) probably occurred at a bvriel depth between 

1000 and 3000 m. a themal maximum which nrrrarponds to the 140°C T,. 

me of fluid inclusions in the sphaisrites. Sans regional uplift 

probably occurred between mimm burial and sphalerite deposit~on 

(sangster et al., 1989). The age of initial uplift oE the Long Range. 

detemihed f m mermorphic cooling ages east of tho Long Range, was 

Middle Silurian to Dewnian (375 - 130 : 10 m.) (Dalhyer, 1977; 

Hibberd, 1983). The youngest date far the uplift. determined Em 

carboniEems radixants thet onlap the Low Rmge Inlier, is carliest 

carboni,ferous (Tournainian 345 - 340 ma.) (Hyde, 1983). Ruthigenic 

ptaasiu. feldspars in carbonate veins suggest that earlier sulphide 

mineralization was Devonian or older (Ar"/Ar"' ages, Hall et 01..

Figtllo 9.1 llpp:~ Catoshs Dolostone Nlcies at the Ore Horizons 

A map of the upper 50 n of the Catosha Fomtion in the 

vicinity of the L Zone and Trout Lake Rock-Matrix Breccia (looation map, 

Fig. 1.4) demnrtrates that arena of abundant saddle dolmlte occur 

locally vlthin and around fracture zones and they are surrounded by 

b-d areas of gray dolostana with leas than 20 \ patches of white 

saddle dolomite. Zones of mrse *parry dolostone arc a light gray, 

medium crystalline rak without patches of white saddle dddte. This 

lithology is nramnly transitional with limeatone at the margins of 

coarse dolostone complexes. Limestone remains in local patches dietant 

from fracture zones and mck-mtrix brecsias.

UPPER CATOCHE DOLOSTONE FACIES AT THE ORE HORIZONS 

\~ 

1 

"C 

GRADE OF 

PSEUDOBRECCIA I 

> 40% SADDLE D 

20% TO 40% SADDLE DOLOMITE 

< 20% SADDLE QOLOMITE 

0 500111

'lrure 9.2 Rciatiollahip between Sphaleritc Bodies, 

Stmcturdl conlours and Rook-Hatrix Brecciar 

Linear ore zones i n th? "peer Catoshe Pornation occur along 

inflections in stmctural contours which represent deformation along 

fracture zones, faults or margins of fine mk-mtrix breosies. Major 

ore me8 occur along the southem nargins of rosk-mtrix breocias. 

Rlth~gh the L Zone in the srruthwert &ends for a length of 4 h, all 

ore bodies arc discontinuou~. Nmsa of ore zones and rock-matrix 

breccia. are identified on the location map, Fig. 1.4).

Plgure 9.3 Clenerations and Distribution of Faults and vein systwa 

A m~nimm of three generations of faults aiong fault 

runes. Synaedimntery faults contml the Dundaries of mck-mtrin 

brecclas and influsnce changer in thickness of the upper Wathuna 

Fomtim. Ore-stage faults constrain the position of ore lenses and 

coarse dolostone facie.. Vei!~ system svrrmnd thesa fault zones. 

Post-ore Easlts diplace warre dolostone/pDhalerlte cqlores.

~iqure 9.4 ~istribution or bate Fault-RelaLed Oolostanes 

in the Table Heed Group 

Discordant halies of flnely cq~talline dolmtme composed 

of oolmitite VII replace the Table Point Fomtion elow late atsap 

faults which displace Eoarse dolostonelsphelerite owisxes of the upper 

Catoche Pomtlon. The pattern of them dolostones in otherwise 

tmdolmitiaed Table mint Formatior. definer the areas of influence of 

late fluids which nigrsted along the faults. The distribution of 

disoordent coarse apsrry dolo-stones which replace Catache limestones 

along late faults is illustrated in ng. 8.2.

1989). 

The epigenetic history of the UjS complexes post-dates nmiy 

311 

buriei dolomitiration (Dolanitas I1 and 111) and pre-dates uplift (after 

Dalanite VII). This hlltary is divided into seven events: (I) Regional 

deformation faulted and fractured the area. (2) Porvssive dolonili- 

ration (Dolomite IV) "round these fractures converted dolostone-toottlod 

liwatones loolanites 11 and 111) to coarse 1mt.h dolostone. (3) A 

second episode of faulting and folding facilitated extsnsive dissolution 

of the cadmates by "pre-ore" fluids. (4) Two main stagss of 

sulphidcs (early and late) crystallized mncurrsntly with fracturing and 

carbonate dissolution. (51 extensiva replacwent and cmntstion br 

saddle doionrite and calcite occurred after post-ore fracturing. 

(6) During the uplift of the lang Range Tnlier regional folds ana Eaults 

Lilted and offset Dls cqlexss. This rotation is recorded in poet-ore 

geopetal seabeants. (7) Ute dolmitization (Dolanite VII) of limos- 

tones along the faults aosurred during or after uplift. 

Bpigenetic D/S -1exes are described in detail and interpreted 

in the next five chapters. lbe nature and evolution of ths strustural 

fruae~rk is established in Chapter 10. The descciption of tne dolo- 

stone/sphaierite bodies ix divided into three chmnoialio chaptare: 

Chilptel. 11 on the preare dolostones, Chapter 12 on the sphslerite 

bodies and chapter 13 on the post-ore dolostones. The history and 

genesis of the D/S -lass Is synthesized in Chapter 14.

10.1 Relative We Rslatiships ot Strvctvres in the St. Deoqe Omup 

Faults, folds and veins in the mine area range fmn faults active 

during deposition to structures fomd during regional uplift. !.ate 

structures ~(XIODO~Y overprint earlier ones along the sane trends (Pig. 

9.3). The various structures an separated into four different ago 

gmps based on theIr relationships to both large scale stratigraphy and 

to celment stratigraphy (Fig. 9.3). 

(1) SrlMedhnrW Faults - The sediloentary thickness of the 

Ayathvna Fomtion end Table Head Grmp varies abruptly ecmr struc- 

tural linearnentr ruch as the Torrent River Fault (Pig. 1.3) 

(Knight, 1986; Knight et 111.. in press). Ths middle and upper members 

of the Rguathuna Formation rsach their maxlouun thickness over rock- 

mtrix hreocias developed along early northeast and north-trending 

f~olts end fractures (sections 4.3 to 4.5; rigs. 4.1, 4.6, 4.7). 

Variable regional thicknesses of theaa units imply differential subaid- 

ence rates in fault blocks which swented the platform at the end of 

the Lower Ordovician and during the early Middle Ordovician IKlappa et 

al., 1980; Jms et al., 1989; Stenrel and James, 1988; Stenrel et al., 

1990). 

(2) 

Esrh Burid Rachva~ and Paultn - Dalostone bodies canposed 

of Daldtes I1 and 111 and fracture cements of blecky calcite and

Uoimites 111 formed along verricei fracture system during early burial 

1'11 

(refer to Chapters 5 and 81. me of these dolomitized Eructuro systems 

cut the previously feulted margins of mck-matrix breccia.. 

Is) miqanstic Veh and Faults - Linear vein syatams contem- 

porary with D/S mpiues 'racture the uppr Catoclje t'omation over 

widthe of 50 to 500 m along the mqina of late faults and omund rosk- 

matrix breociaa (Fig. 9.31. Lacliy there veins deeply penetrate the 

Catoshe mmtion. Associatel! faults oriented northesst-sc hwst, 

east-west and northwst-southead exhibit small-scale (1 - lorn) vertical 

displacements. Northeest-trending fold axes and southeastcriy dipping 

reverse faults imply northwest-diroetad rsgionsl conpression. 'lhe 

dirfering gsnerations of vain cements fran early sphalerite to saddla 

doinlte dmnstrate that fracturing accurred thmughout the crystal- 

lization of DjS canplexes, fmn Fractures cuntrlling distribution of 

blornite Iv to veins cemented by Saddle Ooimite 0 (me graphic illus- 

trations, Figs. 1.6, 5.7. 6.1 and 8.2). 

The assooiation of tectonim, dilatent fracturing, dolmitiaation 

and sphalerite precipitation is based on several observations: 11) 

Faults laally contml dolostone fasiar (Fig. 9.1). (2) Suipllides end 

saddle dalmited teminete at faults lotserved in the K, L and T Zones, 

Figs. 10.1 through 10.5). (3) some sulphide mineralization post-dates 

feuits and overprints them (observed in the I', east L and T Zones). (4) 

suiphide and saddle eolmite-cemented veins are localized along flexures 

end faults (Figs. 9.1 to 9.3). 

(4) 

mte cmss-mttb Rnrlts - '~hrse generations of faults 

displace dolosrons/aphalerite canpl-s up to 53 m. Early northesst-

trending reverse and thrust faults 1%. Klii "evil Fault, Pig. 1.3) and 

77.1 

later north-trending n oml to steep reverse faults (eg. ~rien's Yaul~, 

Figs. 1.3, 1.4) displace west-dipping flanks or aamctrical anticlincr 

such as the Mike Lake Anticline. Lote right lateral atrika-slip accinrr 

on ram of these faults, such as Ibrrent River Fault (~lg. 1.3). 

Narrow, linear vein systems vary in width Emn 20 to 70 n, are 

stratab3und aver thicknesses of 3 to 40 m, and strike hundreds La 

thausal138 of metres along the gently folded nargins of mck-matcix 

breccies and Peults (Figs. 9.3, 1D.1). 'me veins arc distribvtsd over 

tl~ick ~tratiglaphi~ intervalB (10 to 30 m1 adjacent to faults and 

bTeEEia margins, but occur in prqressively higher stratigraphic levels 

and in thinner stratigraphic intervals away frm these stmstures (Fig. 

10.2). This mttern is also repeated along the strike or vein systems 

(Figs. 10.2, 10.3). 

Fracture zones parallel not only the boundaries of main trend 

faults (IS, Pig. 10.4) end rock-mtlix breccia* (In, Fig. 10.4). bul. 

also Imp around 100 to 300 m-long northwest-trending crass-faults (Ill\, 

Fig. 10.4) and follav the axial treees of folds between these cnms- 

faults (111, Fig. 10.4; Fig. 10.5). Vein system also reflect the 

discontinuous and en echelon neture of main trend hinge and scissor 

faults (Pig. 10.2). Inflections in trends of vein system cross-wer 

from the end of one fault to another en echelon fault (Fig. 10.2; 1IB. 

Pig. 10.4). Fractures in theas areas deeply penetrate the Catoche

Figllre 1O.i Structure of the T Zone 

~slo~i~~ship betwren Sulphidea, veins. Faults and Roek-Matrix Breccias 

a. The T Zane ore bady (loacation. Pig. 1.4) flankn faulte and the 

margins of mk-matrix breccia=. Sles?es of pyrite war between these 

.iLructures and the ore. The bale of sphalerite ore in the T Zane varies 

rystemati~ally frm local deep areas 1120 feet below the Wmme mxker) 

along northeast-trending faults to 95 feet 1b.w.m.) between faults and 

05 to 15 Seer (b.v.m.) in parallel ore lenses sway Im main structares. 

0. In crass-section A-A' stratabound veins in the upper Catoshe 

Porntion occur along major structures. 

C. vein system are shaped as-tricslly. Cross-hatching 

indicates zinc minexallzation. 

D. Sphalerite occupiee inclined veins in finely crystalline dolostones 

ibiack) and sheet lnegaporeb in pseudobreccia beds (white). Part-ore 

veins are steep and cemented only by saddle dolomite. 

E. vein* in the T Zam .V~Q prefersntially dip to the southwest.

Piaura 10.2 structure of ths East L Zone 

nslationshlp between are Bdly Isopachs, Hinge Faults 

and Structural contours 

urn lenses and coincident vein syztems occur along the foldsd 

flanks af faults and rock-mtrix breceias and cross-over between en 

echelon fault Lanes and along cmsr-faults. me era occupies a W b OF 

fractured strata in section A-R'. Thick, deep ore acurs along faults, 

whereas, thin, late ore occupier upper beds along the swthern flank d 

!he L Zone (seetion 8-8'). Section II - A' is Illurtretea in larger 

scale in Fig. 12.6 and section B - 8' is shnm again in FL~. 12.4. The 

L mil 1s located on Figure 1.4

- 

Figure 10.3 Southwest L Zane 

natalled Cross-sections a€ an Upward Migrating Vein System 

The southwest L Zone (lmation, Big. 1.1) tenninatsl along e 

cross-fault. At this msition the ore occupies a 13 n thickness d 

frsctu1.4 d0lost00e~. Plle vein system besmss narmm and linear in a 

northeasterly d~rsction where fracturing is restricted to 3 to 6 m of 

strata at increasingly higher stratigraphic levels. Ssction A-A' 

ulustrater the lacelizetion of ore/fracture zones along faults and 

flexures. Dolostona zebra bands are inclined toward faults (section A- 

A'). Finely orystalline dolostone beds (black) ere s-nted end 

displaced along reverse faults lsestions &-AG, 8-8'). Fracturing and 

mmr.ra1ization is confined balw and/m between 1.5 to 3 n-thick finely 

crystalline beds (section C-C').

~igur~: 10.4 ~istribution of ~yper of vein Syetema 

A mp of ura distribution denonstrates the vnrisd relation- 

ship 01 vein myst- to mck-matrix brsccias (shaded), faults and 

structural contonrs. The psition of vain systemscan be oategorired 

incta five types. 

I &long major Structures IR Breccia Margin 

IB Fault margin 

11 Deflections IIR cross Fault 

IIB Between Hinge Faults 

I11 Between Major strvctvres on the limbs of mooclines

j~urr 10.5 SLructvral mntral by a Cross Fault at the K Zone 

A northwest-trending cross-fault alters the northeast trend 

of a vein system which hosts the southwest K Zone (lacation, Fig. 1.41. 

The trend of veins as;3 +he strike of bedding is mtatsd parallel to the 

aroas-fault. The ore occupies fractured dolostones in the vicinity of 

the cmrs-fault and along fracture zones (section A-A'). Alocq the 

Iault (inset) mineralisation replaces the upper portion of beds and 

cementa eastward dipping and horizontal veins. mat-are veins, c-nted 

only by saddle dolmite, are both vertical and wed-dipping (n dlagra~11. 

The change in fracture orientation aver t he indicates e change in tha 

direction of extension as displacement occurred along the cmrs-fault.

'omation. Mineralized velns ore related to early deformation along 

Uleae structures, prior to significant Iault displacement. The discon- 

tinuous, en echelon faults reamble fault brirlges and the corresponding 

132 

inflections in vein systms are cmmreble to transfer eotlos between the 

faults (R-y and Wsr, 1981). 


Vein systems are mgosites of several generations of structures 

from Initial cmpressional fractures to late diletent ones. A gently 

folded stratigraphy is extsnsively fractured and brecciated around steep 

reverse and "0-1 faults (Figs. 10.1, 10.3, 10.5, 10.6). Nie fractur- 

ing is confined to thin, gray dolostone beds, 10 to 50 cn thick, over 

vertioal sections of a limited 5 to 30 m thickness. One to two metre 

thick beds of gray dolostone ccmanly iwede the vertiml penetration of 

veins, and thue, they caa~nly form hawing and footwalls of vein 

systems Wig. 10.3, section C-c'). 

In detail, vertlcal and lw angle veins segment the thin, grey 

dolostone beds into 0.5 to 6.0 m lenmhs which ~no~nly display o 

reverse sense of displac-nt (Fig. 10.6; PI. 10.1). Horizontal veins 

part the tops and bo*tm of these W s end inclined veins flatten 

toward the bases (Pl. 10.la: Figs. 10.1, 10.6). Host veins do not 

S~ODS-CU~ EOII~S~ dolostone beds, but instead merge with sheet megaeores 

' 

and irregular solution cavities (Pig.. 10.2, 10 .6).

~ig.~r~ 10.6 structure OE the F Zone 

oetalled Nap and Cmss-section of a Vein Colplex 

The F zone (looation, Fig. J.4) parallels the faulted margin 

nE a msk-wtrix breccia and makes a right angle bend along a crosr- 

fault. Fr?stUring occurr; amund reverse faults in the centre of the ore 

zone (aectian A-A']. nost of these fractures ere inclined to the south 

in diagrm). Sphalerite mineralization OEN~S along reverse feulte and 

is mnfioad shove bands of =*bra dolostone, convex upward features which 

meqe with veins in overlying beds (sections A-A', 8-8'). Mineralized 

thrust faults displace finely crystalline dolostone beds at the bend in 

tho ore zone. Plates ~O.la, 13.1~ and 13.1s illustrate portions of wall 

seetion B - B'.

;I. 

Piate lo. I Veins and Vein-Brrscies 

iau angle veins in e Finely crystalline dolostone flatten towardo 

the base of the bed where they merge with a sheet cavity in the underly- 

ing pseudobreccia bed. Reverse view of the left side of section A-A' in 

pig. 10.6. F Zone. I n scale. 

b. A reverse feult offsets dolohtone be& which locally fm dilatcnt 

vein-brsssias. A view 09 pert of section A-a' in Fig. 10.7. North L 

Zone. 1 rn scale. 

c. Finely crystalline dolatones end sphalerltes are bncc~ated almg 

dilatent veins adjacent to a fault I sm as inset In Fig.10.5). 

Sblinter breccies in the upper middle suggest hydraulic Eracturinq. 

Adjacent to the croas-fault In the southmst K Zone. Pen waartes 15 

L' .

Figure 10.7 Crosa-section of Reverse Fault - Sear Breccia Structures 

Ilm underground drifts north of the L Zone exposed rare 

~~orthwest-south~a~t cross-sections of fracture zones. Beds ere gently 

Ialded and displacsd along reverse faults. Pinsly crystalline dolostone 

be

Thlee gemrations of structures, which comprise the vein systems 

include early cqrearional struoturea and ore stage and post-orc 

dilatont fractures. The nature of each of these generations 1s describ- 

ed end interpreted in ths followin? three sections. 

10.3.2 Early Cmpressionalstlucbe 

Reverse Faults, the cen:ral structures of mst vain systems, occur 

within open upright Eoid structures (Fig. 10.7; P1. 10.lb). I'hese 

structures are senerally northeast-trenaing end aip to the southeast, 

they locally diverge around rock-matrix breccias and other Eeu1l:s (Fig. 

10.1). Hany low angle fractures in gray dolostone beds are probably 

related to the reverse faults (Pig. 10.61. Gray doloston. beds are 

locally buckled and displaced in a reverse ssnse along these fractures 

(rig. i0.3). Mineralized bedding plane thrusts also cut these bedr 

(Pig. 10.6). 

Intamr&ation - Northwest-directed region(r1 CwRresbion gently 

folded and displaced beds of the upper rtotoe Fomtim along reverse 

112 

Eaults. Deformation pxopqated outnard fm these faults by fracturing 

thin, brittle bedr of finely crystalline dolostone and was confined 

betwen thick be&. The fracture systems confornad to the gmetry of 

thick dolostone bodies leg. msk-natrix breccies) and to large faults 

which both caused looal rearrangement of canpresaional and extensional 

features.

10.3.3 Dilatat On Stage Fractures 

Netwas of sphalerite veins vary €ran horizontal to subvertical 

($0') and are generally discontinuously ~lustared (Pig. 10.6; Pl. 

lo.la). Inclined veins generally exhibit preferred orientations, 

343 

dzppine the sane direction as revsrre faults and opposite to the ganeral 

Inclination of bedding (Pigs. 10.1, 10.5, 10.6). 1,-diagrms oP over 

1000 measurements frm 8 areas emphasize the importance of low angle 

veins with preferred orientations which tend to dominate populations af 

conjugate fraotvres (Fig. 10.8). 

Evidence of -11-scale solution collapse scours loeally through 

out vein cwlexes. mst fractured and brecciated doloatones, howewr, 

rwin as & BrLU m ~ i bi-eccias c (Figs. 10.1. 10.3, 10.7). Slution 

collapse Peatures include: (1) local thinning of coarse dolostons beds 

(Pig. 10.3); (2) local sagging of overlying beds several metres in areas 

5 to 20 n vide (Pig. 10.7; PI. lO.lb); and (3) displacement oC gray 

doleatone fragwnts several metres darn into solution cavities (Pls. 

7.3d. 10.lb). Large -scale, ore-stage solution bresslas =warable to 

HVT deposits in East Tennessee and Poland (MsEomick ct al., 1971; 

Devlynski and Sass-Gustkiewicn. 1986) are not observed. The largest 

breccia bodies, 10 to 40 m wide and up to 100 a long, occur in the Long 

Hole Stope (Pig. 10.2), along cross-fault? ig. 10.3) and in the North 

L Zone (Flg. 10.7). Although these bodies are highly Irectured, they 

display only loinor collapse. Spar brecciar are diacvssed further in 

Chapter 13. 

- 

Int- - Steep reverse faults diqleced beds and Iw anqle 

to horizontal tension fractures opened as extandon mcurred in subhor-

~igure 10.8 orientation of Veins in the nine m a 

over 1000 veins Mere nearured in eight iosalities acmss the nine 

area. Stereoplots reOOId the density of intersection points of poles to 

veins with 1% of the area of a 1-r hemisphere pmjection.Canjugste 

sets or &ins an, present loost places, but these populations are 

dminated by groups of low ewie velna dipping either to the southeast 

or ,8orthwest. The inslined, listric veins imply extension along 

silbharimntal planes relative to mimum Bhortening in a horizontal 

direction.

I 

i~ontalplmle8. M B X M rhortming was directed horimntelly from tho 

southeast. These veins, with consistent orientations. opened in 

relationship to defomtion along reverse faults and probably in 

response to fienvai slip on the lids of mnoclines (sles and Peugs, 

.Id,. 

1986). Fracturing and dilation intensified around faults where abundanl 

veins penetrated mimum thic*nssse. of stretigrsphy. 

solution collapse played an inportant, but subordinate role in the 

tomstion d vein emplexas. Sagging or collapse of beds generated a 

variety of structures: (1) vertical veina in gray dolostone beds above 

sheet cavities (Pigs. 10.1, 10.3; PI. 10.lb); (2) lacsi coilapse of 

Irawnts of these beds into wacavities 1 to 2 m in diameter (Pls. 

7.3~. 10.lb.c); end (3) dwndmpped ssvnts of beds or blmkr of 

stratigraphy bounded by outward dipping faults (Pig. 10.2, section A - 

A'). In the long Hole Stape cw~lative dissolution over 30 m of 

stratigraphy caused Isqe-scsle faulting and collapse (Pig. 10.2). 

The orientation of post-ore veins generally differs fro. ore-stage 

ones. steep, post-ore veins wt earlier lw angle ones and locally 

exhibit oppoaite inclinations (Figs. 10.1, 10.5). Post-om sets of in 

angle veina also occvr ,however (Pl. 10.la). Myriads of late ore-stage 

and POS~-O~E veina and megabrsccias surmund cmss-bults whish general- 

ly post-date early ore (Pig. 10.5; PI. 10.1~). mese late veins 

significantly enlarge vein systems frm their earlier extent (Pig. 

10.9). 

Post-ore saddle dolomites c ant all ore-stage velns. post-are

~~gure 10.8 r.mss-ncction of a vein System North of the I aons 

A vein syste. northeast of the L Zone and Tmut Lake Ilreccie (Fig. 

1.4) developed along an inherits synsedlraentam fault. Curing ecrlier 

history this fault was the hc.r of karst brewiatim and deep discor- 

dant dolmitiration. Linestone solution resulted in mck-matnx 

bmcciss and solution residue layers. Stratabound sphalerite 

~insraiimdtion occurred i n the middle OE the vein q l e x alonghide rad 

beneath pyrite mineraiiaation. mst-ore veins significantly increased 

Lhe size of the vain system Mth laterally and vertically.

...... _. POST-ORE 

i VEINS 

'120' .LAYER- 

DISCORIIkNT 

DOLOSTOHE LIMESTONE 

CROSS SECTION OF VEIN SYSTEM

fractures and hrecdos. Both Saddle blrmitrs Rand B cement npiislrr- 

like vein-breccias d dolostone and sphalerite wall rack (1'1s. b.la, 

10.1~1. These late cements sigtlify that port-on defomtlon reopened 

".@-stage fractures as well as creating new ones. 

3819 

IntemmtetLrm - Vhe upper Catache Porntion fracturd extensively 

and ell veins dilated prior to cementation by saddle dolomite. wtcn- 

aion also reopened previous nulphidc-cemented veins as saddle dolmite 

subsequently filled thm. Lateral extension related to late vertical 

fault movement opsned new, steep fraotures which cut lo* angle ore-stage 

veins (Figs. 10.1. 10.5). Oefomation along faults produced abundant 

frastu~es, vein-breocia and dgabrecciar (Figs. 10.3, 10.7; PI. 

10.lb.c). Fluids disaolvd carbonates along the velnr to for. metre- 

vide oevities which filled vith collapsed frapnts (Pl. 10.lb). 

Elevated pore fluid pressures probably cdined vith tectonicelly- 

mntmlled extension to frachrs the dolostones and to naintain open 

pores. The linear vein systems besme river-like condults or sills in 

which strata and fractnres sxpanded under elsvated pore fluid\ pressurc 

(Fyfe ct el.. 1979). Cenented veins and finsly crystalline dolostone 

beds f omd teaporary awicludes end allowed pore Elvid pressures to 

periodically exceed the tensile strength of the rook, causing hydraulic 

fracturing (sg. Phillips, 1972; Prioe, 1975). Wall mcks splintered 

into nmsrwr fragments during at leaet three phases of fracturing (PI. 

10.1s). 

Typical rnraic breccias remained &y as aphalerite and saddle 

dolmlte gradually oemcnted veins and solution pores.. This rslationrhip 

s~wests that initial fracturing and rotation of fragments crested pore

space and lack OE large cavities prevented collapse. If prr Eluid 

PIOSSUIB weeded lithastetic pressure for extended periods of ti-, 

harever, the fhidn alone ~ould have maintained the pars space (Fyfe et 

al., 13l9). A prolonged period of extensional stress duriw c-ntation 

also oould have contributed to dilatsney. 

10.4 smmq 

Regional caopression reactivated northeast-trending faults and 

seconaary fracture sybtms that affected the St. George Grmp during 

,,in 

deposition, subsurface brat and early burial. Host fracturing occurred 

in linear, stratabound areas of extonaion along four types of struc- 

tures; (1) main trcnd faults, (2) rock-matrix breceias and other large 

dolostone bodies, (3) short cross-faults and (4) transfer zone8 between 

discontinuous faults. On a large scale entire vein systems lag. I. and T 

zones, Fig. 10.3) can k considered zonss of extension between major 

northeast-trending feults and around rigid dolortone badies (mainly 

rock-matrix breccisa). . 

Fracturing and extension occvrred thmughout epigenetis dolmitiza- 

tion and rulphide minsralization. The entire nine area was fractured 

during early cmpzsssion. Ore-stage fracturing ana dilation fomed lou 

angle veins as northwest-directed regional cmpressi~n warped beds 

around reverse faults and rock-matrix breccia bodies. Significant 

vertical displssemsnt took place along cross-faults during late are to 

pt-0t-B stages. This vertisal mvement generated stesp veins and 

extensive fracturiy as mst early tracturns were reopened. 

Solution collapse and hydraulic fracturing pmhahly played i wr-

tant but subordinate roles. Dolostoner locally collapsed above metre- 

scale aoltltion cavities. Significsnt lrscturing and aolutian along 

faults fomed namw, breccia bodies, 5 to 30 m thick. Elevated pore 

fluid pressures mnbined with tsctonic-mntrolled extension to mintuin 

dilatent conditions during the ementation by sphslsrites and saddle 

JSI 

dolmites, and at lsast three time. cmvned "splinter" breceiation during 

hydraulic fracturing.

~~ay, cadiurn to coarse crystalline ~oinite IV with its chamc- 

teristic xenotopic textures (Pi. 5.5a) overprint. oady burial hlos- 

tones (blomites I1 and 111) (Pl. 5.1 E.91 forming prvasive dolmitired 

bodies in the Catoshe Formation (Fig. 8.2, discvsrion in section 5.6). 

In marre &lortone/pseudobr~~oia beds uniformly coarse, gray pre-ore 

dolomlt~s are referred to as -se matrix dolostones (Fig. 8.1). In 

contrast to earlier stratigraphis dolostones which generally are not 

related to faults these bodies occur locally a mnd fractures. Cmrs- 

cutting veins and pares filled with sphalerito and post-ore dolomite 

indicate the pre-orc age of the doloatones (Fig. 8.1). Post-ore 

Dalmits V in turn overprints and effectively destroys these pre-ore 

dolostones where thsy fom cowrely crystallins beds (Chapter 5, PI. 

5.191. 

Re-ore, red CL Dolmite 1V occurs in three fom: 

(1) Host Wrtant. it locally replaces nattier, beds and fault-envel- 

oping W ies oE medium orystalline type Dolomites 11 and 1x1 (Chapter 5, 

Pl. 5.lf). There gray dolostones ocevr and are preserved outside arwr 

0E psaudobreccia, in the upper 10 to 20 n of the Ultoche Formation and 

within deep discoreant dolostones (Fig. 7.1). I few inrsrbeds of this 

form amr between pseudobreccia bedo. Suoh interbe* are only dolomi- 

tized w n d fracture zones in Dls ca@lexes in contrast to extensive 

early fine dolostones. In Figure 3.1 gray dolastone bed "55" is only 

p-jrtislly dolomitized in the lhestone section in contrast to extensive

~lo~tone beds at "30" end "66". 

357 

(2) Dolaaite Iv also appears as minor intercrystalline cementa in early 

fine dolostonss. 

(3) %all patches of Dolomite IV occur in pseudobreccia beds (Pi.5.lg). 

These relics within beds of later replacwnt dolortone (V) 

suggest that Dolomite W was once mch mre extensive. 

In the swse dolostone-pscudobremia beds patshas and bands of 

gray to black, d i m wstalline dolostone (v) replaae precursor 

limestones and form e mae msteix &lostme amvnd finely crystalline 

mttles of farmer early dolostone (I1 and I111 (PI. 5.5~; Pig. 8.11. 

The gray dolamites whioh -rism this coarse matrix dolostone possess 

the dull red ffi signature of post-ore Dolmita V and are partially 

replaced by Saddle Dolomite A (PI. 5.5c). AlthWgh the replaenent 

crystals are post-ore, cmss-cutting sphalerite and eaedle dolomite- 

filled pores and veins imply that the gray dolomites replace a pre-om 

dolostone. The preservation of ralio petches of Dolomite IV (PI. 5.19) 

supports this conclusion. 

Int-tam - During the early stager of rerlional deformation 

linear fracture systems developed; warm, fomtional brines then 

migrated along thm, pemated the surrounding i-tones and dolostones 

and, in time, altered them. Increased temperature and salinlty of 

f-tion waters promoted conversion to dolomite (Mines, 1971) with 

xenotopis texture. (Ow9 and Sihley, 1984). Abnoml Hg abundsncea, 

c0,lCa ratios andlor elevated temperatures in these early, allochthonous

zitier could have generated the presuned doldtlzation of limestone 

metrix. (Lou W/Cs ratios in mat lamtion waters inhibit dolmltiea- 

tion of limestones in the deep subsurface (Mormr, 1982; Land, 1981)). 

Rltarnatively, pervasive dolmltizetion of the upper Catoche Porntion 

oocurrsd during early burlal (TI and 111) and Dolomite IV largely 

replaced these dolostones. The cannon appearance of Uoimite IV as s 

replac~ment mineral supports this latter hypothesis. The destructive 

rsorystalliretion (V) of eoarse rnatriy dolostones, houever, erased the 

petrographic evidanoe of their prehistory. 

It is pnswed here that epigenetic fracturing of the upper 

Catochc Wmtion led to extensive dolontltfzat!on aE the lineatones. 

The nature of the dolmitization IN] varied frm replasMient of beds, 

354 

discordant bodies and mottles of aarly burial dolomites (I1 and 111). Lo 

conversion of burrowed 1- weckastones to finely crystallins dolostones 

and alteration of line grainstone matrix to coarse matrix dolostones 

[fig. 11.1). These dolortones dld not entsnd laterally beyond fracture 

zonal; as earlier, ubiquitous dolomitiration (1.11 end 111) had done. 

mrmg later epigenetic =vents finely crystalline beds fractured and 

coarse dolostone litholcgies suffered extensive dissolution and recrys- 

tclliaetion by post-ore Dolmite V.

Ylgure 11.1 Evolution of Cwrsc Matrix mlostone 

e. early burial dalmitea (I1 and 111) Eomd dolortone mottles 

viLhin limestone beds and dlscordent dolostones along steep fracture 

mnea and marqigins of rock-wtrix brecciaa, 

b. Coars* matrlx dolostone (TV) recrystallized some of these 

precursor &lostones and replaced beds of pelddel limestone in the 

vicinity of epigenetic fractures. w types of fine to ..dim orystel- 

ltne gray dolortone are shoun: (1) extensive early fine dolostones 

lvhite. 2 nr beds) end (2) prs-om, epigenetic beds of local extent 

(stippled, 2 m beds between mottled dolostones).

12.1 lntrodu~tim - Relatinship hetma sphalerite Bodla, Vein 

Spatem and m a e mlostanelr 

Stratabound and dilisontinuovs sphalcrite ore badias end lo* grade 

mineralized zones are curvilinear, shoestring shapes, lo to 60 m vide by 

3 to 30 m thick and 1000 to 5000 m long. They occur within vain systwaa 

that encircle mok-matrix bressies or follow nearby faults (Pig. 9.2). 

They are also enveloped by even lamer bodies of coarse doloatone, 30 to 

300 m wide by 50 m or mre thick (Pigs. 7.1, 9.1). Limestone is present 

6 m or mre below mineralization and only rarely ere lateral remnants 

fovnd in the pmximity of sphelsrite (Pig. 7.1). 

The sphaleritb badies are conpasites of the two mjor generations 

of sulphides which crystallized during ragional events of fraoturing and 

faulting (descrikd in Chapter 6). early sphalsrites ocoupy early, 

narmv vein sprtms vhlch aurrovnd most faults end md-matrix brecciar. 

Late sphalerites werprint sets of veins which cut earlier sulphides and 

surmund late, ore-stage faults along the L and T Zones (lacation MP, 

Fig. 1.4) Dcadian faults and folds deform the sphalerite bodies and, 

thus, constrain the timing of sulphiae dewnition to a pre-Devonian age.

12.2 Sphalsrite Boaiea: meir Internal Ra!mwork and Zinc Grade 

12.2.1 Desoiption 

Distribution 

~n ore lens comprises 3 to 30 mineralized coarse dolostonel 

pseudobreccia beds, each with 10 to 4O\ rlnc in 15 to 601 spholerite. 

These beds are intercanneoted by sulphide-cemented veins, the "conduits 

of mineralizing fluids", which cut barren gray dolostone Interbeds. The 

intervening gray dolortons beds dilute the ore grade d lenses down to 

an average of 8% zinc (Fig. 12.1; PI. 12.lb). 

ore zones and vein system are nearly coincident. Beds within ore 

zones are intensively broken -pared to wtlying areas. Gray dolostons 

lnterbeds in the central and lwer portions of ore zones ere highly 

segmented by mnjugete vein sets. nonnal and reverse faults and spar- 

cemntad, mosaic breccias described in Chapter 10. These interbeds are 

pmgressively less disrupted toward the tops and sides of are bodies 

(Figs. 10.1, 10.2, 12.1). abundant loegapores in cmrse dolostonone beds 

of highly veined areas give nay to uniform fabrics of mesopores and 

replacsment dolastone in less fractured portions of ore bdier. 

Mineralization is usually omcentrated in the upper half to upper 

third of pseudobreccia beds, where it prtioiily fills ubiquitous areso- 

pores, precipitates amund the rhs of mgapores and replaces gray 

natrix and rattle dolostone (Pigs. 12.1, 12.2; 91. 12.lc.e). In many 

cases sphalerite is confined between an averiying gray dolortons inter- 

bed end an underlying discordant, 1 to 10 aa-thick band of graylblack 

dolostone in the middle of the pseudobreccia bed (Pig. 12.1, 12.2; 

P1. 12.ld). Elsewhere, mraivs sphalerite is distributed uniformly

Figure 12.1 Cmsn-section of an Or* Bady, the K Zone 

maer of 5 to 15 1 zinc ~oupy the uppsr portions of up to 10 

pseudobreccia beds dong a steep reverse fault. The lenses are bounded 

a h by finely crystalline dolostone beds and belw by curved, dismr- 

dant gray dloatone bands (illustrated in Pls. 12.ld 13.2a). These 

bands also Porn inclined upper contacts on rhe north side of some ore 

lenses. Mineralization along the fmlt end veins inte~mnnects the 

lenses. Pyrite -curs above and along the north side of the zinc ore. 

The K Zone (location on Fig. 1.4) is situated on the gently folded 

flank of e mck-mtrix bnccie. It i s surmunded by pseudobrecoias 

which contain abundant saddle dolomite to the mth and are transitionar 

i?to gray dolostoner and rook-matrix brsccias 50 m to the north.

Flgvre 12.2 Mngitudinsl Profile of the Larsr K Zone 

A longitudinal sross-section of the lower ore beds of the K Zone 

(location map. Pig. 1.4) is Petched from an underground rlb pillar just 

belw the portal. Early yellw sphsleyitc generally occurs m the upper 

portions ol pseudo-breccia beds %bow discontinuous, cuspate bands of 

black dolostone (illustrated in Pls. 12a.d: 13.2a). These black bands 

plobably aoted as inpsrviovs boundaries, but also could have prwided a 

souroe lor sulphiae reduction. (Any mganic or H,S content was renavad 

during later events.) 1;egapotes within ore beds, shown on the inset, 

ore cemented in sequence by sphalerite, black geopetcl dolonrite, saddle 

dolomite and calcite (illustrated in PI. 12.Z). The hprtant geopetal 

dolomites ere tilted and parallel the dip of bedding, indicating that 

the beds were flat-iyini during ore deposition. Early yellow sphalerite 

mineralizer beds to the right. Lltter brown rphalerite teocscrs after 

yellow crystals in wamres (PI. 12.2f) and fams ore beds st the left 

and bottom of the pillar.

LONQITUMNAL PROFILE OF THE LOWER K ZONE 

.,- Om. -** --Am A,,* NWY) Do- .Am. a=-0 .D rs*o

~bfe 12.1 DisLribution of Sphheierite in coarse Dolostone Beds 

a. massive ~ ph~l~rit~ (2"s) mcurs along the base of fomr sheet 

mvlticr and the margins of vsim occluded vith saddle dalmite. 

zcbm fabric on the Iwer left i s curved dovnrard toward the vein. east 

K ~ onc (Fig. l.n), undergrmna rib pillar. I n scale. 

h. contact of a rphaleritc body. On the right sphalerite occurs 

=I-g veins and horizontal oavities (arms at right) and replaces 

surmunding dolostone. (R). The sulphidss end a t an abrbrupt mtaot with 

e saddle dolmnite-rich bed larrov a t left) anaociatd vith mst-ore 

veins (all'white veins inclined to the left). saddle daldtes partially 

replace aulphides elong,the 'ragged' contact. SodMvest end of the L 

zone (lmatian, Pig. 1.41. 1 m scale. 

c. Massive sphaierite (WIS) OCNrs in the upper portion of a cwrse 

&lortons bed beneath an impervious, finely crystalline dolostone. 

sqvthrest L zone (location, Fig. 1.4). 1 m soale. 

d. Haarlve yellow sphalerita 1ZnSI minenlizer the pornus dd-portion 

of a pseudobreccia bad. Discontinuous black dotostone hands arur just 

blow the sphalerite. East K Zone (location. Pig. 1.4). 1 m scale. 

s. shalerite breacias IS) and megacrystalline srrddle doldtes 

-py the Pmer site of sheet cavities just beneath a finely orystal- 

line dolostone bed. Tabular layers 'sf mllofom sphalerita that once 

coated the cavity rwf have mllapsed (arm). T M e. 50 m scale.

Jb5 

thmughout pseudobrsoeie beds or decreases in abundance to trace amoatts 

towed bases. Mineralization ends laterally either over narrow grade- 

lionai zones or at abrupt contacts (Fig. 12.1). 11 abrupt, 8 to 15% ore 

grade zinc abuts against barren pseudobreccia either at a discordant 

gray doloatone band or a zone of abundant, 60 to 801. white saddle 

doldte (Pig. 12.1, PI. 12.lb). Zinc abundance= at gradational 

contacts diminish gradually to less than 3% wer 1 to 3 rn widths end 

locally over 30 m (Pig. 12.3). Disseminated mineralizetion broadens out 

over 100 to 300 n s t the ends of ore bodies (Pigs. 9.2, 12.3). 

12.2.2 mterp~tation 

Fluids migrated horizontally through vein systems and aulphides 

prscipitatad in veins and pores of surrounding coarse dolostone beds. 

High grade concentrations of sulphides crystallized within narmw, 

highly pemeabla mnes of abundant veins and large oavities and massive- 

ly replaced adjaoent coarse dolostone bed.. Fluids diffused brwdly 

along strike into pomus dolostones and disseminated sulphidcs precipi- 

tated where veins end cavities were not abundant. 

In individual coarse dolostone beds, metal-bearing fluids Plowed 

through the upper parts of beds and perticularly elong csvities. 

sulphides precipitated along the rims of cavities and in pores of 

surrounding dolostones. High grade mineralization commonly atoppsd at 

underlying gray-black dolostone bands, probable armisludes which also 

could have caused local rulphhur reduction. The bed-top ore lenses imply 

that the sulphidss precipitated frm a buoyant fluid that migrated to 

the upper parts of beds below imprvious fine dolostones beds. Post-ore

~iyure 12.3 Detailed Zinc Grade Distribution, P Zono 

line mineralization in the I Zone (location map, Fig. 1.41 occurs 

over widths of 10 to 50 m. Ore grade concentrations of zinc abruptly 

contact barren dolostone to the south. M the north and eaet zinc 

abun+me dimmishes to trace eolunts over widths of 10 m. Cloaely 

spaced test holes for open pit development provlded exccptiensl control 

on zinc grade variation in the F Zone. Einc gradea of 5 to 7 '1 in the P 

Zone were lover than most other zones which asvDraya 8 % zinc.

saddle dolomilea partially replaced sphalcrito end, in particular, 

produced sharp boundaries at the edges of lenses. 

sphalerite cents pores and replaces dolomites. As a c-nt it 

lines and fi11e vain. end solution pares and isopechwsly costs bresoia 

fragments (Pls. 6.la.g; 12.lb; 12.2c,f). Replacement nodes range fraa 

wholesale replacement of portions of dolostone beds (PIS. 12.la.b.c; 

12.2a,b.d) to howsneour dissemination of individual or groups of 

Crystals in coarse dolostones (PIS. 6.3e; 12.2b). 

(1) Vein and cavi* mfneralizati~o €oms centimtre-scale layers 

fracture and solution negapms (PIS. (.la; 12.1b). nost 

mineralized veins occur in gray d0106tme interbeds, whereas f omr 

JW 

solution oavitiea appear as sheet megaparer in pseudobreccia beds. Pore 

cents Coarsen outwards in mllofom bands from very flnely crystalline 

to fibrous to coarse, primtic sphalerite (Fig. 6.13). Latar saddle 

doI.miL. and calcite occlude centrss of pares. Sulphides also penetrate 

the wall mok in paeudobrescias as 10 to 15 m-vide helaes of disscmi- 

nated to massive sphrrlerite (PIS. 6.le; 12.26). 

Sphalerite is commonly thickest on cavity Plwrs and locally 

ebsent on rmfs (PIS. 6.1a.g; 1Z.lb; 12.2c.d.e). Sphalerite also occurs 

on the tops of gray dolostme fragments and isolatd dolostonone nttles. 

This pattern of minersliration, characteristic of W T deposits, is 

colloymially called "anm-on-mf" texture (oder and Hook, 1950).

a. 

Platr 12.2 Sphalerite Ore Habits 

roeleroed mnsttes (medium gray) typical of msssive early tan-brown 

ore. Laminated finely crystalline aphalcrite, black geopstal sediments 

and white saddle dolomite fill porss between rosettes. Swle fro. 

massive ore beds edjacsnt to the cross-fault in the southwest K Zone 

(location, Pigs. 1.1, 10.5). Scale in sentimtrcs. 

b. ~osettea of early rod sphalerite replace gray marsr matrix dolo- 

stones and ere partially replaced by saddle dolonita (am$). Ssnple 

f m massive red ore in the G Zone (location. Fig. 1.4; section, Fig. 

6.4). 1 En soale. 

c. Disseminated sphalsrite crystals oonu. on the tops of gray dolo- 

stone nwttles (snw-on-nof texture) and nucleate on residues along 

rtylolites. Swle fro. the L Zone (location map, Fig.l.4). 1 m scale. 

a. Rosettes of rphalerite replace dolostone nucleii. Saddle 

dolomite cmnts surmvnding solution pores. Swle f m the F Zone 

: (location nap, Fig. 1.4). Scale in centimstrea. 

e. cavity mineralization. Sphalerite (maim gray) precipitates the 

kse of a fomr sheet pore and as disseminded mineralization ilmund 

dolostone lnottles (black). Post-ore veins cut and breccicito sulphides. 

saddle dolmite cenents veins and sheet pores. Swle fm the L Zone 

(location map, Fig. 1.4). Scale in cantlnatres.

E. Naraive sphalerita consists of rosettes of ycllo* sphalgrite (pale 

gray) with bmun %halerite rims developed on resistsnL cores of early 

dolomitized Wrrows. I honey-comb network of solutlon pores between 

rosettes are Iilled ulth gmpatal blaok dalaaite and white saddle 

dolomite. Typical of msslve early yellolr ore in the lover K Zone 

(location mp, Fig. 1.4; Figs. 12.1, 12,2; P1. 12.ldl. Scnla in oenti- 

MtrB8. 

17 1

covity-base precipitates ere also tern "mud in the cellar". These 

textures can be used as geopetel indicators. 

Spar breacias with saddle dolwite E-nt also contain sow 

sphelerfte, generally disposed as c thin rim c emt around fragmnts. 

Zinc grade in breecias is generally low (1 to 3%) compared to Lhut 

arwnd pseudobreccia cavities (10 to 25%). This style is cman nlong 

highly breesieted cross-faults and in the North L Zone. 

372 

12) Heasive dalerite laslly replaces up to 1% of coarse dolos- 

tone beds (Pig. 12.1; Pi. 12.la.b.c). Massive mineralized beds cmnly 

contain &!I to 60% sphelerite I25 to 45% zinc). Sphalerite typically 

OEEUes as clusters of crystals and msettes which either coalssse or are 

separated by dolomite. These crystals form both presipitatss around 

dolortone (PI. 12.2f) and pertially or completely replace thosr corns 

(Pl. 12.2b.d). Surrounding geapetal redimants and saddle dolomite 

smnta indicate the pre-filling origin of some sphalerites (PI. 

12.2d.f). Elsewh-e, however, massive beds of 50 to 10 % sphalerita 

replace significsnt munts of dolostone (Pl. 12.2a.b). 

(3) Disaainetd edminenrlles&Im in pseudobreccia is widespread and 

characteristic of beds with partial mineralization around cavities and 

in the transitional boundaries of ore bodies. Typically individual and 

coalewed sphphalerite cryetsls in pseudobreccia beds sit on the taps of 

grey dd10o.t"ne mottles at the base of mesopores (Pl. 12.2~). Sphalaritc 

is also disseminated ~ ithin the intercrystalline pores of mtrix 

dolostone end decorates residue-rich styiaiites, like "pearls on a 

necklace" (Pls 6.3e; 12.20). The one to three aphaierite generations 

at each precipitation site only represent pert of the sulphide cementa-

tion history in corrtrast to the wltiiayared cavity c maW (cowarc 

Pls. 12.2~ and 6.W. Zinc grades in beds of disseminated sphsleritc 

vary from trace quantities up to 2%. 

In sumer,, ore bodies exhibit ell three habits of suiphides. 

Met ore badiea contain 2 to 4 heavily minsralired to massive ore beds 

which assay between 25% to 45% zinc (Fig. 12.1). In valned and faulted 

areas, vcln end cavity mineralization rims end surrounds sheet cavities 

311 

in the upper half of pseudobreccia beds (PI. 12.lb). Massive s~haierila 

"mpleses" coarse dolortones adjacent to veins and cavities lPl. 

12.ls.b.c). crystal msettoa in these beds ncarly coalesce, onluda 

mesopores and partially replace dolostone wttles that they envelope 

(PI. 12a,d,E). Disseminated sphalarite i3 distributed in lwer halves 

of ore beds, the laargins of ore bodies and thraughout low grade mineral- 

ized zones (PI. 12.2~. Fig. 12.1). 

12.3.2 Interpratatioa 

The different hablt types reflect differensas in focused vs. 

diffuse flow of ore fluids and in rates of nucleation and procipitstion 

of cry&tals. In veins and cavities fluid flow was Lacused l~long large 

pores and fluids only ppervaded 10 to 30 n into ths surrounding dolos- 

tone. In nassivs sphalerite beds, fluids dlffused thmvgh ths entire 

beds along e network of intercrystalline mismpores end mesopares. 

Pibmur rosettes of sphalerite crystallired rapidly on nusrous nuclea- 

tion sites as tins was rapidly "d-d". Solution pares enlarged during 

minemli%ation and coarse cryctals precipitated the last c-ots. 

Disseminated sphalerite, in contrast, crystellired Ircw fluids which

1741 

pervaled unironly pr011s dolostonas a lnetre to hundreds JE metres awaq 

from open eonduire. Spblerite in these areas precipitated as coarse 

crystals at local sites such as residue-ricll stylolitcs as a result 01 a 

dilute supply of zinc and sulphur.. 

12.4 me Feoay and Dev~lqsent OE Ooposite aerita Bodies 

12.4.1 Introhotion 

Ore is conononly located 19 to 30 m below the Lop oE the Catocha 

Porntion IWom Elarker). Equivalent mine level mubere of b6 to 100 

refer to feet below the Horns Marker (See Chapter 3, Plg. 3.1). The 80- 

90 level is the most s m n ore bed. "55. 60 and 66" gray dolortone 

interbeds conmanly form hanging wells or bacm of nine workings. 

Nineralization bstveen "30 and 50" levels is rarely ore grade. Ore 

locally reaches deap levels between "100 and 165" (ic. 30 to 52 r below 

the top a£ the Ultoche Fornation) (Figs. 10.1, 10.3). 

Typical 10 to 15 m-thick ore zones are esymetric in cross-section 

ahller to the geometq of vein systems which they overprint (Figs. 

10.1, 12.1. 12.4). Relationshipa were well docmnted by the author end 

mine staff through serial sections of mpped faces and drill lnle 

seotions of all dried eones. Representative sections are illustretcd in 

Chapters 10 and 12. A nerm (3 to 10 mwide) area of stratigraphically 

deep ore, here ~alled the "keel", c mnly occurs on one side of the ore 

body. The "keel" surrounds high angle fault(s1 and fraccurad m ks and 

is cmmmly situated adjacent to a fault or fine rodematrix breccis 

body. Exonylles of wall d osmted faults can be seen in Pis. 7.la and

~imre 12.4 Cmbs-section thrmgh the east end of the L Zone 

n cmss-peetion through the east L Zone (section B - 8' frm Pig. 

l0.z; L Zone lacation in Pig. 1.4) Allvatrater the aswtric gemetw 

and -site nsture or the ore body. Thick and stratigrephically desp 

ore is situated slow a fault/fractura zone. A narrow lens of early ore 

oscvrs north of the fault. Several broad lenses d late sphalerite to 

Lhe awth step up the stratigraphy fron a deep "keel" adjacent to the 

fault. In both early and late sulphide lenses Pmgresaiveiy younger 

rphaierite precipitates ofsvpy lower and outer edges of the bdier. 

nesrive sphelerite beds in the L Zone have ore gradas (10 to 20 8) 

mnpsred to the F m e (3 to 9 (, see Fig. 12.3) where arlnsrelirstion 

i s mre patchy and disseminated.

13.2~. he footwall and, In places, the hanging wdll of tho ore M y 

clMs up-section in 3 ta 10 m wide steps away from the keel to the 

wter -0 of the ore body (Fig. 12.4). 'Che UP-section clink is 

wcmpilnied by vertical thinning an6 lateral spreading of thn ore baiy, 

deereasing in thickness f m 10 to 30 n at the "keel" to 1 to 15 m al. 

the outer edge end IncRasing In width from IS to 70 to 200 m In the 

111 

sane direotion. In places ths keel is situated abwe deep frectu~as and 

discordant dolostones (Pigs. 8.2, 12.11. The vertical mnLinuity of 

them narrow, deep structures is unlmam. Rare mcvrrences of pyrite 

and sphalerite are scattered in the underlying deep, discordant dolo- 

stones. Oeep drillinq beneeth the wet I. Zone and the A Zone trscad 

pyrite 50 m bela* me horizons elong fractured fault zones which 

penetrate belw the Boat Harbour Fomtian. 

The stratigraphic $asition of ore varies along ea well as acrasr 

strike. Hanging walls and fmtvalls abruptly rise and 811 3 to lo m 

svery 100 to 500 m elong strike (Figs. 10.2, 10.3). The stratigraphic 

position and total th1cknesr ai veined and mineralized beds is con- 

Lmlled by [major structures (Pigs. 10.2, 10.31. Sphelerite penetrates 

deep strata (33 to 50 m below the tap of the Catoche Formtion) at cross 

fractures, brecoia mrnars and along some faults. Ths Long Hole Stope 

of the L Zone et a breccia corner is an ebr- exqie of anmlously 

thick ore with a deep footvall and high hanging Hall (Fig. 10.21. Ore 

bodies cannonly terninate laterally at them srees of deep mineralize- 

tion (Pig. 10.1, 10.3). 

Early and late sphalerites, described in Chapter b, occur in 

separate oe cmpsite bodies in the mine area (Fig. 12.4, 12.5, 12.6).

Ptgure 12.5 Distribution of Early end Loto sulphidea 

in the central L Zone 

m the central L eanc aulphide tadias decrease in age with 

distence nouth frm the T mt me fine msk-matrix breccia and the east 

L Zone fault [lowtion nap, Pig. 1.4). A m e of pyrite ocnvs between 

the breccia and a narrow body of early sphalerites. Broad lenses of 

late sphalcrite partially werlap earlier ones and form several sqarate 

bodies. Bends in ore bodias arc related to fracturiw along cmss- 

Iaults which acquired pronounced offsets during lato or* stages.

,, ,D,ISTMUTION OF EARLY AND LATE SULPHIDE 

P b V A b P v A / 

a v b i 

0 v 

- 

0 1OOm 

LATE SPHALERITES 

EARLY SPHALERITES 

PYRITE

Figuzo 12.6 Sulphide Zonation, Long Hale Stap of the L Zone 

cross-sections of the Mng Hole Stqe of the L tone illustrate 

srruclural contmls on the distribution of sulphides (location on Pigs. 

1.4. 10.1. 12.5). 

~~~i~gioal cmsa-section A - I\' is an interpremtive compilation 

of drifts mppcd aoroas the top by R. cmssley, cmss-sections wn- 

stmcted I- drill core end obse?vetron or pillars 10 m *id- by 30 n 

high. outward-dipping faults flank r.rtioa1 faults which mntml deep 

mineralizstion. bloatone beds in +he area an !amken and sag. 

Sphalsrlte zonation. Early pulphides f m a narrow, vertical 

body. Pyrite occurs aidng the top and north Plank. The earliesf 

rphalsriteh appear only in the upper partion. mter yellow sphalerlte 

€oms cement rinds after earlier crystals at high levels and the mly 

ore twaral.da the base of the bay. 

Late, prdminantly yellow-bmm, sphalerites occupy the mein 

Idulted and brscciatad body. Latest yellor-black sphalarite pnsipi- 

tates the lmr end ~ter portions of tho ore bady, in a aimilaz fashion 

to earlier mineralization. 

The dlstributim of early and late sphaleritea sqgerts that prior 

to eerly mineralization local fracturing occurred along the north aide 

UE the L mne. Widespread fracturing, braociation end displacement 

along outward-dipping feults did not occur, however, until the beginning 

of late mineralization.

WLPHlDE ZCNAilON, LONG HDLE SIOPE. L aM 

GEaCUCM CROSS-SCTKW A-E 

SRULem2Cw.mwW~I-A'

Widespread, early sphelcrites constitute approximately 4 million short 

9s 

rons in the nine area. Late sphelsritc ura only occur* along the linear 

tmnd of the Lend *r mnes where it adds 3 million tans to fom the 

largest ore bodies in the mine area. The Iollowing descripLinrl uf rhs* 

development of the sphalerite todies ia divided into a discussLon or Lhc 

early and late mlphidss. 

12.4.2 Bsrly @halarib Bodies 

Barly sphaleeites are distributed thmughaut the mine area as 

narm, 10 to 35 rvide lenses with a vertical to horizontal ratio cf 

2:l Lo 1:l. Both ore and low-grade minsralizetion lie within 50 rn oi 

breccia margins and faults ompared to late sphelerites which occur 

further from these stmctures (Fig. 12.6). 

n typical ore bady is chsracterised by precipitation of susses- 

sively younger sphalerites down through the ore body: Early red 

sphalerits and pyrite -r in the top 1 to 5 a. Tan-bmwn sphelerites 

dominate the middle 5 to 10 m. Yellow sphalerite is disposed in the 

hasel 5 to 20 m Iligs. 12.4, 12.6). Pyrite is also ?nly concentrat- 

ed in a am- mne along the vertical contact betv~. .,re ore Wy end 

gray, medium cryrtalline dolostoner. Ths develowent of early sphaleri- 

te is separated and desoribed in four stager of mineral paragenesis. 

Chaptsr 6 describes petzcgzaphls and gsochmicai details. 

Pyrite mloes - The pyrite generally occurs as vsry flne 

to fine-sized franiwi2al crystals disseminated through gray doloatonc. 

Locally It is a first stage cement along pores within pseudobreccia 

bede, appearing before or interlayend wlth the earliest sphalerites.

Steqe 2, Red Wmlerita - early red sphaierites a1 the tap oi ore 

bodies are disposed in narrow, anaatmring strmgerr that oiso contam 

millor pyrlte and galena. They ere finely crystalline, connvlnly display- 

109 fibrous to dendritic habits. They fom only a minor portion of Lhr 

ow bodies. 

Stew 3, Tan- S~halerlts - Pibmus, tan-brown sphalcriles 

precipitate In the lniddic to upper parts of moat early ore lenses as 

mealteb and handed, oolldomm cemnts arwnd cavity rime (PI. 12.2dl. 

his aphalerlta also occurs in cmrs-fractures ss massive, 8 to 13 m- 

1Rl 

thick bodies. 40 to 55 rn beim ths top of thc CaLoche Porntion i the 120 

to 165 foot mine levels). Crystal rosettes in there massive beds 

coalesce, replace preurwr dolostwes end occlude mst remndery pores 

(pi. 12.2a.b). These msssive spheierite beds conrtltute sme of the 

highest grsdes and tonnages per area at the mint. 

Stage 4, Yeltn S~bderite - mrs~, prismatic yellow sphaleritss 

which DCEY~ in the bottom half to two-thirds and outer extensions ot ore 

lenses generally cement the edges of ~esopres and cavities (PIS. 6.la. 

12.2~"). Wundant rosettes of yeilav sphalerits also make up massive ore 

beds, 3 to IS m thick end I5 to 30 m wide, which constitute nearly tn- 

thirds of the ervly ore lenses within the a, X and L Zones (Fig. 12.2; 

Pl. 12.2f). 

Hmogenieation tmperatures of fluid inclusions fmm yellow rphal- 

erite vary thrwphout the mine area. Annnaloueiy high T,.'s i1MI to 

las'c) occur in stratigraphically deep sphalerites in the B and H Zonar. 

Incl~slons fm the L and T Zones have l',, lnodes of 140qC, whereas ones 

from the P Zone range fmn 95% to 115'C (Fig. 6.3).

12.4.3 mte sphalerita Wies 

Late yellow-bmm to yellow-black sphalerites occur ar ore b-diea 

in Lhe L and T Zones where they constitute !nearly two-Lhirdr or Lhe 

t0L.1 ore tonnage and as areas of low gredm minerallzaLior8 to thc 

southwe~t and noccheast of the L Zone (U, V. I4 aud Ulack Duck mnes) 

(lwations an Plgs. 1.3, 1.4). The latest yellow-black sphaleritc in 

widely disseminated throughout the region. 

late whalerite ore bodies are ggnnerally tchular in crass-section 

381 

with a Vertical to horizontal ratio nE 3:4 to 1:5 (Fig. 12.4). l'hey "re 

situated as far as 200 a from faults or rock-matrix brocclas where they 

clnrtitute separate ore lenses or the up-dip and upper stratigraphic 

portions of c-site bodies (Pig. 12.4). Hinerallzation and veining in 

these areas is m enly restricted to a few beds in inrsrvalr only 3 to 

10 a thlck (Pig. 12.0. &Km1ous thicknesses of iats sphaierite (up to 

30 m) occur locally along cross-Faults and in the Long Hole Stape (Pigs. 

12.5, 12.6) 

Late sphslerite bodies locally diverge f m mrtheasteriy trends 

whem they loop around cross-faults in what are colloquial>y temd 

8"whaop-da-&osc' (R. C-rley, pers. sonnr. 1980)(Figs. 9.3, 12.5). They 

also occur as mltiple, parellel lenses in the oaat L Zons (Pigs. 9.3, 

10.2. 12.5). 

These ore bodies, ainllsrly to the early ones, are charaeterircd 

by the occurrence of svcceseively ywnger sphalerites dovn s~llon and 

toward the up-dip, outer edge: Yellow-brown sphalerite occurs in the 

upper 5 to 15 m. Latest yellm-black aphaleriter are disposed in the 

basal 1 to 5 m and over widths of 2 to 10 n an the outer edge (Figs.

12.4, 12.6). A two stage dcveiopment of lete spholeritcs is descrihd 

below. 

InL; 

Stage 1, Yelh-bmm Sllheiletito - Coarse crystals or yollov-brown 

sphalerite occur in the middle to upper portions of late ore bodies boll, 

BS w in and cavity c ents and es ursive beds. Tlmy isopachously 

cement brecsias af early sphalerites where early a ~ d lete bodies rvsrlup 

(P1. 6.1f). In contrast to esrly tsn-brown rphaieritcs with fine, 

€ibtous crystals in collaforn and msatte habits, these crytitels are 

disposed in patches of coalesced coarse crystals which partially replace 

dolostonos (Pl. &.la). 

Stage 2, Yellor-blaok - Yellw-black crystals, the latest ore- 

stage sphphalsrites, are disposed in the bottom third and the edgss of 

late ore bodies, but also occur throughout the ares as minor ore 

concentrations in early ore M ies and as widespread disremlnsted 

crystals. The typical mrse, prlamtic crystals s omnly oecur as vein 

end vug cmnts, hlt iocs.lly they form mssivc ore beds. Thoir uidc- 

8pr-d distribution is related to regional netvorka of late veins and 

mesopores in coarse dolostones. The range and distribution ol 6'9 

values of late sphalerites exhibit a decrease frm 2I 0100 in the 

centres =f ore bodies to 18.8 oloa in outlying areas (Comn, 1982; this 

study) (rehr to discussion in Chapter 6). 

U.4.4 Interpretation of Mineral mation 

The geometries of bodies of esrly and late sphalerite c onfad to 

the changing dinensions of fracture systems as defomtion cantinuad 

throughout the ore stage. Early sphslerites mineralized inarrow fracture

2OllC8 within tens O€ metres of fatdts (?ig. 12.4. 12.6). The position 

of sniphides at tops of fractured aquifers suggcsrs that wan, atai- 

beadng fluids were buoyant, rose upwards within the Fatoche bmatisn 

and probably displaced denser local formation waters. Fibrnls to 

dendritic red spheierite rapidly precipitated f m iortinl imn-rich 

fluids. Fine pyritc precipitated where the fluids encountered and 

pamated fine gray doloatones W e , beside snd below vein systems. 

Fluids progressively migrated thmugh Lower stratigraphic i~vels as 

sphelerltes ceolented upper beds and as carbanate disaoiution increased 

permeability in underlying dolostones. The acidic products or sulphide 

preclpitstion and carbonate undersaturation fmn tluid mixing pmbabiy 

caused this dissolution. Finely crystalline, rlbrovr rosettes and 

collafom deposits of tan-brown sphelerite rapidly and extensively 

precipitated in the upper to middle portions of the eymifer. Finally, 

386 

coarse yellow apheierltes mineralized the lower partions of vein systems 

as they grew slowly on extensive veins and solution prer that had 

fomd durlng the first influxes of metal-beitring fluids. 

a separate phase of regional compression and displacement aiang 

fevlts folilloved the depitim of early sphalariter end propagated folds 

and fractures up to 200 m frm these faults. This fracturing affected 

thin packages of bads up dip f mn faults and produced laoping paths 01 

fractures smund cmss-faults. Late sphaleritea precipitated rdthin 

these late fraotvre system in downward and outward youngin9 scqnsnces, 

silnilar to early bodies. cmparativcly coarse yellw-black crystals 

precipitated extensively in pores as they foned the lower and outer 

portions of late ore Mler and vldely disseminated crystals throughout

the area. 

The diseontinurms nature of bath early and isle ore badier was 

relstsd to one or mre reasons. Piratly, local ohbundancrs of 1,: in 

rock-matrix breccinb and other eady dol-tone Wles could lrsw 

sntalrjed sulphide precipitation, os in the organic brown dolorloncn in 

the southeast Nissouri Viburnum district (J. Vlets, pers. ccm. 1988). 

Extension amund mok-matrix breccier and between northeast-trending 

reults, a second possible rearan, provided lose1 sroaa of pmability 

lnta which ore fluids migrsted. Faults beneath deep fracture mnea 

served es vertlerl mndults for the mlpretion of ore fluids. Various 

features support ths latter hypthasis. weep disoordunt doiortonar 

around these faults contain scattered sulphidea. Thick deposits of 

mssive. tan-bmun sphalerite crystallized where fluids entered deep 

JR'I 

ftactu~e mn.6 in the upper Cetoche oma at ion. he positive 6'"s values 

(24 to 28 o/oo) and high 4,'s (165 to 18SDC) of these dmsits probably 

represent the colnpoaition of relatively warm ore fluids with unfrection- 

ated sulphur ee they emanated f m dnep faults. 

12.5 Dnstreints on the Internratation of Ore Genesis 

12.5.1 Int?d!xtion 

Features of the Daniel's Harbovr dsposit nsrrar the poariblE 

Intmrpr8tation of the subsurface environment of are dewsition. The 

imrtant :onstrsints are dlrcvssed in terns of how they e fkt inter- 

pretstion of the rexting, timing, nsture and source of ore fluids and, 

Isatly, the pathways d these fluids.

12.5.2 Sattlng 

ore deposition was an epigenetic, deep, burial event. Thin is 

inplied by eler4ted fluid inclusion temperatures, pressure ~olvtion 

features in ore-stage doloatones end suggestion of lithosletic fluid 

pressures. A minimum estbted depth of 100 to 1000 I!, uccountu lor 

known rover rocks of the Table Haad and h s e TicW:s Groups and Lhe 

~ h a Arm r Allochthon. Thsmal mtuletiol of conodonts (CAI of 2 to 2 

112; Nalm and Barnee, 1987) suggests further burial to 2000 to 3000 ln 

(Harris, 1919). Near Cape Noiolan lack oP correlation between elevated 

themal maturation of oonodonts (CAI of 4 to 5) end rphalerite Plvid 

inclusion %.'a (11O0C1 i ~lias, however, some regional upllft pdoe to 

culphide deposition (Songster et a].. 19891. 

Ore deposition is intrinaicslly related to regional tmtmim 

which is intarpreted to be the early stages of Aoedian tlotonism. The 

rphaterite badies overprint fracture systems whish devclapsd before, 

during and after ore depsitlon, These fractures forned the conduits 

for lzterel fluid 11ovmnt. Deep fracture mer and discordant dola- 

stones along northeast-trending faults also suggest that the fluids 

mved vertically along these fractures. Theae vsrtlcal conduits may 

have enabled bvoyant ore fhids to transport Pb dir~ctly frm basement 

source*. 

P'5.3 ring 

188 

Ore deposition occurred long after the onset of pressure solution 

and crystallization of aarly burial dohiten (I and IT), follar~d 

epigenetie Dolonite Iv and pre-dated basmnt uplift. Pre-ore dolmites

(Iv) attd sphalerite overprint stylolitea and early hurlal ~Iolunitas (11 

Illq 

and 111) vkich fomd during Middle Ordovician huriei al tltc tim of Lho 

Tacaoic Orogeny. Regional sondont alteration iwlio.; lh.lt m>luraLiun 

occurred after burial beneath the H*r Arm nllcrl~lhon. l'lleac rrl.1- 

tionships suggest a maximlo age of ore daposltion in the Uppor Ordo- 

vieian, after the 'raconic Orogeny. 

coeval fracturing and displacerent along steep Ieulta Is vei,l~ed 

to regional oolnpression and fragmentation of the avtochthon during the 

early stages of ths Acadian Omgeny. The Tacooic defomlion daes no1 

have such s penetrative effect on the ailtnchrhon (Cavmd and Wiiliams, 

1988). The oarlisst "Acadian" tectonim in central Newfoundland end Lhc 

White Bay area is dated as Silurlan (423 to 428 ma., Dunning et nl., 

man). 

Laser "'ArY'Ar dating of K-feldspars cemented with sphalfrite In 

the region indicates an age of 35C to 310 m. (Hail et al., 1989). 

Nunemus faults which displace the ore zones are relsted to broad 

folding and fragmentation of the autochthon cwvsl, with the uplift of 

the ~ong Range Inlier. The age 01 the upiiEt is no older than Silurian 

and no younger than early Carboniferous (Visean) (Hyde et al., 1983; 

cad, pars. oom., 1988). 

In m!~slusion, there various constraints suggest that apllalerite 

deposition occurred during the early stages of the Rcsdian Orweny. 

possibly during the Silurian. It post-dated the Middle Ordovician 

aso on is Orogeny and happened before the uplift of the lang Range Inller, 

an event with broad age mnrtraiots. The apparent pre-CsrboniPeraus and 

possible Silurian age of this uplift, however, precludrs that the

~minnralization was n Late Paleozoic event 

12.5.4 Nature and Snvce of the O n Pluids 

Fluid6 preserved in the aphalerite inclusions arc Ihypcrsi>lise 

brines with 24 uriqht % NaCL end a canblnatior .f Cu. K ibt~d Mg chlor- 

ides. Such brines are typical of Eomational fluidr of ncdinlentary 

basins (White, 1968; Sverjensky, 1983) and beslnal fluids which have 

passed through, resided in and interacted uiLh metanarphosed basement 

mcks (Kelly st al., 1986). This origin is mn1i-d by I.ho positiv? 

6"'s values (I8 to 28 o/oo) of the sphalerircs, which imply derivation 

of sulphur €ran Lower Paleozoic sen dater aulphate (Claypool et a!.. 

1980). 

Pb isotop data and hoaogenization tenperaturea of fluid in- 

clusions auggest that the fluids travellad Irm deeper sarrse amas. 

The non-radiogenia Pb was probably leached f m feldspars in the 

Grenvillian basement or arkoaes at the base of the sedimentary pllc 

(coron. 1982; svinden et al.. 19%). Pluid incldrion T,.'s (sode=llO'C, 

nar~185°C) are higher than the expected thermal mhum caused by 

burial (120DC at 3000 n depth) and, thus, suggest heating of fluids in a 

deeper socrse erM. 

Much of the chenriatry of the ore fluids r-ins'unk,oun, however. 

The ore fluids were probably one of t m main types: (I) ecidis fluids 

whioh carried D th metal-chloride coplexea and reduced sulphur 

(mrjsnsky, 1986) or (2) neutral to alkaline brines that tranaportco 

metal-cnnplexes, but no reduced sulphur (Anderson, 1913, 1983). A 

single fluld *ith metals and reduced sulphur car. repeatedly generate

ulphide precipitation sa regionally extcnsivc layers .sad produce 

reversible ji~~olutlon/precipitation reactions (Hcclinnns el al., I1,U0; 

svcrjensky, lra6). rhcae fcaturcs arc characterini~c 01 I hc ~nimnicl's 

llarbour deposit (Chapter 6. Fig. 6.1). Laal clliqc#letre aiiicil icdl ion 

1n the vicinity of fuults iaay also rellcct ~hc, .acidic snlurc or rluld:;. 

The suwivai of acidic fluids teavciiing through cnrbonatcs is qucstion- 

able, houever. The fluids mst mintsin high partial PCCSEU~~S OI W' 

1s) 1 

md an abundance of Ca to prrvsnt carbondtc dissolution and buirerirq of 

the acidic brines (Anderson, 1983). 

oxidizad brines with a neutral to high pH could nairllnlll mctolr i!, 

solutivn as they pars through carbonates (Anderson. 1973, 1983). 

~uiphidss wuld precipitate either where SO. in the ore fi>lld is rcducwd 

Lo H,S or where natal-cnpleues mix with another livid containin? 

reduced sulphur (Mderson. 1983). 

12.5.5 Pathww~ of the Fluida 

netal-bearing fluids in other MVT districts ore comniy inter- 

preted to have migrated up dip E m shale basins into shallow subsurface 

carbonates leg. Jackaon and Beaies, ?967; Leech and Haran, 19861. 

Brines dewatered Iran basinal shales dgnlte under the Force of =Wac,. 

tion, tectonic cqrassion or gravity-drivm lnetearic fluids recharging 

f m tectonic uplands (oarven, 1985). There ncdsis generally presum 

that the hasin - platform transition is relatively undisturbed. (These 

models ere discusse' in chapter 14). 

In western Newfoundland the basinel sedhents were tectanicaiiy 

enplaced on tap of the platform during the Tamnic Omgeny. Fluid

migration prior to and during early phases ot Lhe Acadirrt urqcny was 

constrained by this -1er tectono-stratigraphic Iranework. Hegional 

cmpr~ssi~n continued to devatsr shales with the formation or rlrlcy 

Cleavegs during the Acadisn Omgeny. Deep crustal anatrr~r to tho cost 

probably caused thermal convection of fluids and releane of wolor, 

*tala end sulphur during mineral transEomtions. 

SLratabound patterns of mineralization and doimitivat~on imply 

that fluids migrated laterally along linear Irscture systems fur 

thousands 01 metre*. The dismntinuova and local natvre of ore kdleu, 

deep dlrcordent dolostones and the Grenvillian signature of Pb isolopea 

suggest, however, that ore fluids may have migrated vertically fmm 

baaelbent depths along steep faults. The sphalerite stratigraphy rhava 

that war. metal-bearing fluids *ere buoynnt and migrated to the tap of 

the fractured aquifers in the upper Catoche mmtion, #here the 

sulphidas precipitated. 

12.6 InCupretat!.oa: Porntion of the O?e mion 

sphaleritca rryrtallised in and around vein syarem in the uppcr 

cstoche Foimtion. The gemetry and extent of early and late sulphidr. 

hdiea varied according to the style of coeval deformation and p:osity 

develapnent. Early auiphides crystallized in nermr, ublqvitws vein 

systems whioh bordered fracture lineaments m d mck-matrix brcccie 

311 

bodies throughout Lhe mise area. Late sulphide badier; f omd only along 

the L mne trend, the maln area of lab! fracturing. These volumtrical- 

ly significant late sphelerits deposits of the L Znne replecd extensive

pul.oua dolostanes along multiple tractlare zones. 

m all ore bodies. sphalerites cryslnliized f m fluids which 

migrated throqgh veins, cavities and coarse dolostanrs. sphalerites 

massively replaced up to GO\ of dolostones proxlml Lo vcins and 

diminished dlstally Lo disseminated crystals. ore grade :~phrlsrilo 

crystallization cmmnly ended at abrupt or narrow gradational cantacls 

wlth barren dolostone. 

.111.1 

Natal-bearing fluids ~oigruted cup cross-faults and locally !up "main 

trendw faults; parsing thmugh deep discordant doiostonvs on their way 

into vein syslenc; (Pig. 12.7). 'The buoyant warm Elulls mse to the top 

of vein systma, spread w t along the upFr halves cE Nnrsc dolarkone 

bedl and migrated latarally along rite strike uE vein trends. As oilily 

sulphider filled pores and reduced pemability In upper levels of the 

aquifer. succeeding sphaleriter oryhtallized at pmgresrively lower 

stratig~aphic levels. At the s mc tin. thick massive deposits of early 

sulphlder were rapidly "dwpd" around srors-Erocturcs, where fluids m y 

have .~sneted from depth. Early tan-bran rphalerites accumlnted as 

correlative millbetre-sized multiple layers in most megapores in the 

mine area. In both eady and late svlphide crystallization %Equencer, 

early rapid precipitation slowed in late stages as coarse crystals grew 

in pores and veins. 

snlphid- precipitation way be attrlbuted to soveral reasons. l'he 

entrence and eqnsiun of ore flulds into the fractured aguifer of the 

upper ~ atmhe oma at ion resulted in significant decrsaser in tempera- 

ture, fluid pressure and partial pressure of m, and an increase in pH 

with carbon; dissolution. These phyrlo-chemicul ohanges muld have

P~yurc 12.1 Model for Gmnd Preparation and Ore oepasition 

schemetic diagrams interpret ground preparation aad ore deposi- 

tion. prior to and during sulphide deposition regional compression 

dirneted twards the northwest and local defomtion along reverse 

caults fonned lineor, stratabound fracture systems In thm anis~tropic 

aolostone stratigraphy of the upper Catochs Pornation. Warn, metal- 

bearing fiuids m y haw risen fmm depth at ioonl, deeply penetrating 

tnnsionai zones along steep, wain-trend faults and cross-Faults. 

Features of the Feeder ames of this hydrogeolagio system inclcde: 

(I) deep discordant doloatones whish penetrate the entire Catwhe 

Fotmation, (21 pyrite and rare sphalerita at deep rtratigraphic levels, 

dnd (3) Lhick, deep stratigraphic bodies of raplily precipitated early 

sphaieritr characterized by elevated fluid inclusion T,;r and positive 

S"S valums, indicative of an unsmled ors fluid with undifferentiated 

suiphur. Ore fiuids travelled outward fm thsse feeder zones, riling 

to the top of the aquifot an8 migreting laterally LOW m or more along 

tllc fracture systems. Distal precipitates siong the rtathund aquifer 

have iwer T,.,R and 6'.s values, indicative of fkid cmilaq end sulphur 

dlffcrentistion.

DEFORMATION 

MODEL FOR GROUND PREPARATION AND ORE DEPOSITION 

MAIN TREND FRADTURE 

_.*- 

REGIONAL COMPRESSION 

ORE DEPOSITlOil

ceused rapid precipitation of lulphides where the fluid entered the 

dquifer. in additic;,, c-n grey to black dolostonea within 

flanking are bodies may have provided 3 & H,S [or sulphide precipi- 

tation. 

t he denrity difference between invading buayant meld-rlch Ehids 

and denser fomtional fluids could be attributed to three or narc 

J9b 

physio-chemical properties: (1) salinity; (2) twerarure; or (3) tntcl 

gab dissolved in fluid. Density differences betwen a halite-saturated 

solution (1.15 p/scJ anr: one with 20% per volume &C1 11.10 gmjcc) is 

only 0.05 gm/cc (Hass, 1976). Fluid inclusion conpositions between 20 

end 24 equivalent wgt. \ NeCl indicate only minor density differencer. 

Since sphalerite fluid Inclusions are only the and product of ore 

fluids, the fomtional fluid is an unknoun. A stagnant 

formational fluid at loo0 nr depth could have besn near halite saturation 

(Hanor, 1978). Il-ratwe diffsrebces of 100'C to 150DC in fluids of 

the sene aalinity generate a 0.10 mlcc density difference. IP the 

fluid salinity varies 10 to 15% the density contrast at there twero- 

tures could be 0.15 m/c./~c iS~hl~xger, 19693. Ham fluids, UO'C to 

20O0c under hydmstattic pressure in excess of 100 bars also could 

dissolve significant munts of BIS and COX 9.5. Although quantities of 

0.5 ppn H,s are scmmnly reported fmm oil field brines, and a manim 

of 03 p p HIS occurs in Alberta oil fields st 1800 rn depth (White, 

1965), the precise effect on fluid density of this anount of dissslved 

&S is unknown. In conclusion, in the absence of a salinity contrast, 

temperature would have the mat amrent effect on density. Abundant 

dissolved H,S and cox gases could alw havs decreased the density.

Thus, Wann to hot ore fluids poaaibly with abundant dissolvad 11,s and/or 

39'1 

co., ros~ thrmgh wler ma possibly 102 nxlre saline formational fluids 

and displaced them at the top of the aquifer. 

Evidence of a warn, possibly H,S, CO,-bearing, ore Iluid lighrer 

than dense, cooler, saline fomationai waters relates to other observa- 

tions: 

(1) A fluid cerrling zino-ehloride smlexas and H,S would have 

less than neutral pH lreduced sulphur model of Svsrjensky. 1901, 1984). 

As the fluid enters and expands into tha fractured Catoche avufer the 

acidic fluid uould in succession: wl, dlssolve carbonate, increase in 

pH a d precipitate sulphides vie the fallowing rwstione. 

2HIS + Cam, --> ZHS- + CB" + H,m, 

Cam, + Ham. --> Ca" + 2Hm: 

cam, + zn4* + Hs- --> ms + ca" + HWI- 

Veeiatlo~ in EOnCentretiOn of carbonate end sulphur species relative to 

pH is eweeased in Pig. 12.8. Saturation af zinc would rise as solution 

of carbonates ewsed residues of detritsl silicates and sulphides 

(Svarjensky, 1984, 1986). Field evidence shnrs thet pomsity increased 

throughout crystallization of sulphides as carbonates end sulphides 

dissolvsd leg. Pls. 6.lf. 12.lb; Fiq. 6.4). 

(2) Decrease of fluid inslu=ion kgenization tweratures away 

from cmar-fractures (Fig. 6.3) correlates with wling of fluids in the 

aquifer with increasing distance f m vertical Peeaers. 

(3) The decreasing 8"s values away f m fracture zones (Fig. 6.5) 

suggest fractionation by cooling of fluid a. it prdgressed through the 

aquifer. such an interpretation implies that the 6ulphur was carried in

a 

~igure 12.8 Variation in Concentration of Sulphide and 

carbunate Species vlth change in pH and 30, 

8. liog of the concentration of carbonar species with respect to 

variation in pH (frm KrauMopf, 1961). Progressive airsolution d 

cerbnate rocks by sulphuric arid carbonic acids inaleares pH by 

incressing concentrations of bicarbonate. 

b. iaq of the concantration of sulphw speolsn vith renpect to the 

variation in pH (fmm Xrauskopf, 1967). Hydrogen sulphide is unstable 

in ~lolutions above i p~ of 1 and the precipitation of sulphiae minerals 

msults. Such B pH change would result fma prajrsasim dissolution of 

carbonate mb. 

c. me distribution of sulphur species and ~llubility ~f Pb end Zn 

vith reamct to veriatlons in the Ingaoity of omen and pH lfmn 

Andeman 1973, 1975, 1983). Pb and WI ere Wluble in salutionb vith 

reduced sulphur only at In. pH's. It higher pH's metals om travel w.th 

oxidisea sulphw rpeaies.

CCR 

10 

-40 

- 50 

TRANSPORT 

' pH 

METAL TRANSPORT

the ore fluid as 13,s. 

(4) The five major sphalerite generations and. in particular. the 

uorrslative millimtrs-scale m da d tan-bmn and yellm sphaicrites 

represent tepcetd aepasitional events. 6'"s values vary up to 5 wr 

nil in successive crystal layers. SMlar stratigrophias in the Upper 

niasissippi Valley (ncclimans et sl., 1980) and Southeast nirsouri 

(Sver)ons!q, 1981) have multiple sulphiae stages with variable sulphur 

and lead isotopic sonpositions punctuated by dissolution surfaces. 

nixed fluid models can not produce on e regional scale aonsistency of 

mlphide d~position, reversible diaaolufion/praelpitation and *lor 

IOU 

Uldese crystal g mth (Mcclinans et al., 1980; Hanar, 1979; Ohle, 1980). 

(5) llbrupt underlying and lateral ore contacts with barren pseudo- 

hreccla sugysst that are fluids displaced fomtional flnids and, mlxed 

only over very "arm transitional zones. This relationship lmplies 

that sulphides mwld have precipitated out of the ore fluids, rather 

than by mixing with a sulphuc-bearing fluid. 

(6) The dense saline fomtional fluids were protably not diluted 

by meteoric water. Hypersaline inelusion fluids in pant-ore carbonates, 

late saddle h ldte B end late non-luninaacent calcite (Pig. 5.5, 5.8). 

support this COOC~YS~O~. Only late fault-relded dolostonss, hemtite 

and sulphetes nay have crystallized fro. Elaids influenced by oxidized 

meteoric waters. Pluid inclusion studies in other districts ('3.9.. East 

Tennessee. Taylor, et. al. 1984; Laisvall, Lindblm, 19%) have inter- 

pretated similar date as nixing of meteoric and saline fluids.

DTEomtional events cnated fracture pomeability end predeter- 

mined pathways of early and late sulphides. Periods of faultiw and 

fracturing punctuated ths history of mineralization and dolmitization 

and, in partimiar, separated early and late Gulphide.. Deep faults 

tapped deep basinal uetsrs, particularly at the intersestions of oross- 

faults and northeast-trending ones. Narrow zones oE deep diloteot 

fractures around faults a~anded into zones of stratamvnd veins in the 

hetemgenwus dolostones of the upper Catoche Formation. Thers curvi- 

linear vein system confomd to the gently folded -gins of rock- 

matrix breccia=, faults and m08s-fa~it6. 

Metal-bearing fluids mal.ed f m depth. Lead isotopes indicate 

that sme or all metals migrated frm basmnt depths. Fluids probably 

passed thmgh vertical fractures which cut narrow bodies of deep 

discordant dolortone. Fluids d-d early tan-hm sphalerites at 

cross-fractures nr thick, stratigraphisally deep, mssive precipitates 

of fine, fibrous crystsls with unfraotionated 6'*S and high fluid 

inclusion h-enization tweraturea smund 170sC. 

The sphalerite ore precipitated in asmetric badiss which con- 

formed to the gmetry of vein system. Sucscssive sphaierite stager 

crystallized in a top to hottm sequence. Early metal-baring fluids 

rose to the tops of vain systems end individual coarse doloatone beds 

and migrated along the strike of veins. These initial fluids pemated 

surmunding gray dolostones and left fins crystalline pyrite. Later 

fluids migrated along loner strata as pemability in upper beds was

mduced. Progressive solution throughout rulphide crystallization 

created porn= d010stone6 beneath and along side early nphalerltes. 

These pores were wrtlaliy omanted by coarse later stage sphaleritas. 

a period of faulting and fracturing after early sphalcrite dsposition 

openad a new syste. of veins along the L Zone trsnd whish was mineral- 

ized by late sphalerites. 

sulphide habit in all ore bodies varied Ira. precipitation e mod 

veins end cavities to massive erystellization of adjacent coarse 

dolortones to disseminated mineralization in dolostones distant frm 

megapore=. Central rgeporea preserved the aulphide history as thin 

mltiple cryst:,' Layers which can be traced thmghout the mine arm. 

Preferred prec~j~tetion at the base of pores occurred by gravitational 

settling of zinc, possibly as a colloid, prior to crystallization. 

'lo? 

Transport of metals by a single acidic fluid vith reduced sulphur 

could have accounted for. the collective features of the Daniel's Harbavr 

da~sit. Warn ta hot (IOODC to lEOeC) and hypersaline (22 to 25 

equivalent weight % NaCI) metal-bearing fluids were buoyant relative to 

local fomtional fluids. High tanperat- and disrolved H,S and W, 

gases pmpelled the fluid to the top of aquifers where it displeoeed the 

farnationel brines. netals and reduced sulphvr covld only be carried in 

the sane f' lid at acidic pH (Nerjeneky, 1981. 1986). This combination 

facilitated the observed corrosion of cerbanetes end sulphidea before 

and during the ore precipitation. me rise in pH induced by carbonate 

~olution caused simultaneous rulphide precipitation. The reducsd 

sulphur &el is ths slnplest interpretation of several features: (1) 

multiple sulphide precipitation layers vith variable VaS; 12) cosval

solution oE carbonates; (3) apparsnt minimal mixing at abrupt boundaries 

DE ore lenasa; and (I) decrease ot e'S values presudly by cooling 

away fzm the centre of fluid flow. 

Alternatively, metal-bearing Eluido were buffered by carbonate 

rmks during transport and, as a result, #ere incapable of carrying 

b'eduosd sulphur. In this scenario cooling and undersaturated lluids 

gensrated carbonate solution and @ H,S in gray to black doloatones 

caused local reduction and sulphide precipitation.

13.i 'LmwUott 

Coarae dolastones of Dolomite v (section 5.1) that form the ore 

gangue and dominate the surrounding carlanates are a post-ora phenomanon 

which overprints pre-ote doloriones and sulphides. mite aparry 

(saddle; dolomites, the mst striking -anent of thase marse dolo- 

atones, clearly post-date the ore-stage sulphides as iata cementa in 

veins end pores. Not only do these dolostonen extensively cement pores, 

but they pervasively reerystalliee and dartmy narlicr dolmitea and 

replace linestonas. The pervasive, unifomly lminesoent character of 

Dolomite V is cmarablc to deep burial dolostones (Lee end Friedman, 

1981). Abundant stylolites along saddle dolmites is direct evidence of 

burial belm depths of 300 m. 

These late dolastones osmr as widespread stratabwnd lithologies 

(in contrast to the llocl sphelerite bodles) in the upper Cstoche 

Formation and other stratigraphic units such as tbs 1-r Boat Harbour 

pornation. They extend throughout northwest Newfoundland where they ere 

ase~ciaM with regional northeast-trending faults (Fig. 13.1). 

Disoordant dolmitizatioa along these faults further affects the entire 

Catoche and Table Point Pormatims. 

In the mine area stratabound, saddle dolmitc-rich psaudobnccias 

(Dolmites V and VI; see aectiona 5.1, 7.3.3) overprint ore bodies end 

extend 5 to 30 lo below and laterally 10 to 300 m beyond them (Pige. 1.1, 

9.1). ~se~dobreccias replace beds tens of metres beyond frectu-, in

~igurc 13.1 Regional Distribution of Epigenetic Coarse Dolostone 

in the Lower Ordovician of Northwest Newfoundland 

COBCS~ spigrnetic delostoncs in the Lower Ordovician St. Geqe 

Gmup ere widely distributed m northwest Newfoundland along northeast- 

Lrending fault systems. In contrast, the St. George Group is largely 

limestone east of these faults on the northeastern portion of the Great 

~0rthe.n Penintula. Thls distribution of doiostone mwests that the 

faults were ivortant mndvits for dolomltlring fluids.

REGIONAL DISTRIBUTION OF EPlGENETlC COARSE DOLOSTONE 

WLOSTONE 

LIMESTONE 

IN THE LOWER ORDOVICIAN OF NORTHWEST NEWFOUNDLAND 

\ 

/ FAULTS HUMBER ZON

contrast to the local occurrenca of sphalcrite bodies along vein 

systems. Broad, up to 1000 m wide, zones of ooarae =parry dolostone 

,107 

(section 5.1; P1. 5.7) somnly separate pseudobreccia fasies from areas 

ol unaltered limestone (Fig. 9.1). At depth. coarse dolostones and 45 

to 65 a belw the tq of the Catoche Pormation where a 1 to 10 m thick 

gray, lnedim crystalline dolostone is transitionel with underlying 

llmstones. Outside of Wens Stratabound bodies saddle dolmite occure 

locally as veins and patches in fine mck- matrix breccias, in the 

Rguathuna Fornation and "hers faults intersect the lwer Cstoche and 

lower Tabla Point Fomtions. 

In addition, post-ore dolomites (V,VI,vII) comprise narrow (20 to 

30 .-wide) discordant bodies that differ in relative age, origin end 

crystal texture. Early vertically oriented, tabular to pipe-like bodies 

are c-8ed of medium crystals of Dolmites 11, 111, IV and V. They 

encircle rock-matrix breocias and underlie faulted and fractured 

portions of ore zones (Fig. 8.2). Late linear bodies ol Wlmite VII 

arc, in contrast, variably fine to coarse omtalline and vugw. They 

com~rise envelopas amund late faults that cmss-cut both the Catoche 

and Table Point Fomtions (Figs. 8.2. 9.4). 

0.2 I.irhoW'ir,. 

Past-ore dolortones within coarse dolostanejsphalcrite cowlens 

(Fig. 7.1) are separated into live types: 

(1) Peevdobnccia - Fomsr limestone beds of peloidal grainstone and 

BUFEBSSD~ gray, coarse mtrix dolostoner cnylosed of mlmite IV 

(Chaptsr 11) are prvasively rscrystallizsd to gray coarse matrix

cloloatones cnyosed of Dolomite V with 5 to 80% white saddle dolmite 

(Dolanites V and VI). Saddle doldte ocours both as s pare-filling 

cnnant and e replac-nt mineral of precvrhor type Iv dolomite. 

dUB 

(2) spar Breccia - In vein syatma pseudobreceies and finely cryntallinr 

interbeds are crxa~nly broken, bressiated and cemented by oleqacrya- 

tallina saddle hlanite IV and VI). 

(3) Darse swm m l m e - Eguigranular msaicr of coarse oryatalilne 

dolnite end saddle dolmita replacs limestones and overprint early 

dolostone (I1 and 111) mottles in the llmrtone. These dolostones are 

situated outside ere-ore dolostone cmplexee. 

(4) Dismrdant Bodies of Grey mlostone - Discordant bodias which 

penetrate the entire Cstahe Formation beneath vein systems ere mpased 

of pervasive early burial dolomites (I1 and 1111, replacement orystals 

of pro-ore Dolmlte N and vug fillings and local replasemsnt by poat- 

ore Oolmite v. Veins and thin beds of saddle dolomite (Vl occur 

locally. 

(5) mte mlt-rslatsa Dimamdark mlcstmea - migranular msalcs of 

fine to medim crystalline dolostones replace linestones and envelope 

late faults which displace the coarse dolostonelsphalerite cqlenes. 

These various lithalogies are describsd in detail and interpreted 

in the following s~tions.

13.3.1 Definition 

TI!= mck nmd pseudobreccia at Daniel's narbmr (Watson, 1964; 

Cming, 1968; Collins and Smith. 1975) consists of irregular mltles of 

fine to medim crystalline gray dolostone surrounded hy coarse to 

megacry$talline whits saddle dolmite. Pseudobreccia was originally 

defined as a nemrphie fabric in lime uackeatones or packstones. The 

frawnts wre identified as 'islands" of either coarse n-rphis 

calcite in otherwiss fine crystalline linestans (Dinantion limestones, 

Dixon and Vaughn, 1911; Bathuclt, 1958) or remnants of fine crystalline 

limestone in a coarsely Eryatelline lithology (e.9. Blovnt and Hoore, 

1969). The frawnts of pseudobreccia wsrs distinguished by their 

irregular shape, indistinct gradational boundaries and that they 

partially enclose the "grmdmass" (Dimn and Vaughn, 1911). 

The pseudobreccia at Daniel's Harbwr, in contrast, is a secondary 

dolostone fabric. Here saddle dolmite both replaces dolomite and fills 

aecondllry pares. ma grey dolostone mottles or "frawnts" are patches 

of equant medium to coarse dolmite with the a m dull red CL, and henca 

generation (V) as the saddle dolomite (section 5.7). The mttlea. 

horever, retain residues end loc.1 chemical imprints of precursor 

carbonates. Replacant crystals grade in sire across irregular 

boundaries between gray mttles end saddle dolanita (Pla. 5.5e.f; 

13.3b.e). Coron (1982) refers to these lithoiogies with undisturbed 

pcinary fabrics as c-type preudobrecciss.

Plate 13.1 Pseudobreccia 

a. Alternating beds of pseudobreccia (white) and finely crystalline 

&lortone (black). Mw angle veina cut the fine doloatones. Horizontal 

gray dolostone bands oocur in the lover half of ths lover pseudobreccia 

bed. Brecciar in upper beds are interpreted to be broken bands aswcie- 

ted with negapores. The lower third of pseudobreccia beds contains 

minor svarvnts of white dolmite. X Zone (Fig. 1.4). Sale is 3 m. 

b. Pssudobreecia bed and gray doloscone interbed. The finely crys- 

talline dolostone has h p t contacts (arrows) with typical pseudo- 

breccia beds with uniformly diatrlbuted wgs and lnttled fabrics which 

be~na planar toward the top of the bed. White dolmita decrwes 

toward bed contacts. H Zone (Pig. 1.4). Scale intervals ere 20 m. 

C. Irrermlar paeudabreccie fabrics emund veins and lnegapores. LON 

angle veins cut finely crystalline dolostone beds. Gray dolostone bands 

which ~ u across t the pseudobreccia bed are spatially related to tbe 

veins. Fomr solution pores filled with breccia end saddle dolomite 

occur along veins and the base of dolostone bands. P 7ms (location, 

Fig. 1.4; part of wall section B-B', Fig.10.6). scale is 50 m. 

d. A former solution cavity in the middle of a paeutcbreccia bed is 

lined by collofm sphalerite (arm) and occluded by saddle dolomite. 

A patch of black dolomite occurs beneath the magapre. K Mne (looe- 

tion, rig. 1.4; cavity-fill, inset in Fig. 12.2). m k is 20 cm. long.

e. Cumd planar hndrries (arrou) mntrol the abundance of saddle 

dolonits in a PseUdobrecciQ bad. The upear right hand portion of the 

bad has nilnor white saddle dolmite. The underlying finely crystelline 

dolortone bed is cut by lar angle veins and vein-breccia.. F Zone (Ykg. 

1.4; part of the wall section 8-8'. Qig. 10.6). Scale intervals = 20 m. 

f. Abrupt, undulating boundary (arm) saperates abundant saddle 

doldte £ma noderate deval-nt in the 1-r portion of a pseudo- 

breccia bad. A flne crystal1.ine dolostone lies between this bed and one 

bela, which mntalne zebra banding. H Zone (Fig. 1.4). scale is 50 om. 

g. Horizontal fabric of gray dolostone mttles in a pswdobrmcia bad 

varies folm thin, irregular and discontinuous stylnattles to continuous 

horizontal bands with abrupt, planar bases end irregular tops. Closs-up 

cf bttm d PI. 13.lf. H Zone (Fig. 1.4). Pen in upper left is la cn. 

h. saddle dolmita at the top of a pseudobreccia bed cements a breccia, 

veinlet, replaoer a Mrizontal mttle fabric and leaves only dlaaeni- 

nated Mtles in the middle of tha bed at the bese of the photograph. 

G zone (Fig. 1.0. Pen is 14 cm long.

Plate 11.2 Gray Dolostone Bands and Zebra Fabrics 

a. cuspato gray dolortone band in the middle of a pseudobreccia bed 

resembles a boundary betwen two fluids. K eone (location, Fig. 1.4; 

appasite cuspate bands mapped in Fig. 12.2). Scale is 1 m. 

b. lkee bends of dark gray dolostone alternate with gray dolostone 

partially replaced by white saddle dolonrite. Light gray dololitone 

bilrzms are press& throughout the mck. Saddle dolomite-swnted 

veiniets cross-cut ell fabrics. C Zone (Fig. 1.4). Scale in centi- 

mtrer. 

c. Zebra fabrics within pseeudbreesias abutting a fault. F~sstured 

gray dolostones are offset along a fault at the left side of the 

photograph. 'Ths inclination of the bands is opposite that of the 

fractures and towards the fault. T 'Lone (location, Fig. 1.4; southern 

fault m Fig. 10.1A). Scale is 2 m. 

d. Typical zebra fabric in pseudobressia. Dolostone bands have near 

planer bases and irregular taps. Early doloatone burra mttlea 

(arms) are preserved in gray bends and pseudobrsecia. A fomr sheet 

cavity beneath the upper band is partially cemented by saddle dolmite. 

F Zone (Fig. 1.4; zebra bands in section 8-8'. Fig. 10.6). Scale in 

csntimetres.

,?. 1xmal ic!bra fabrics nsmc1iAr.d rll.h rn~qmslcrl gnly Bnlu~:lunc htxil;. 

1U$ndli nra inclined lowards vnrl Ira1 rr,lclc!rrui. 1. 1.1s. vl$li.o awas 

saddle &lmIte CF~CIILX mgaporc~ U~:r:ocial.od wil h veins 0.d !illcot 

sII,, 

~i8vll.i~~ bcnoull8 doloatarnc intcrbcdl;. I, Y,o.ul#tr, a1 crr,mi-lsul~. Yip. I .a. 

wale Is I to. 

C. Yormcr sheel porcu botwoen zehr;~ bilndu arc Fillad in rcqlsncc by 

%plx~lcritc, blnck geopclal dolomilo and whllc %ilddie dolmito (arm*). 

&I: t.ha top ot 1.1,e photo sadale dolomite conmntr; il rwui tun: Illill cti1.s i 8 

rebn bond on4 r;phalerlLo ccnent. I, zose (Locsllun, Fig. 1.4). 11.mcr 

handle is 40 cm long.

Plate 13.3 Ps~udobre~cia Textures 

a. ~scudobreccia (white saddle dolmite, black matrix dolortons and 

grey early burrow mttlesl abruptly ?mderlain by a burmw-nwttlad, 

Einely crystalline dolostane. Saddle dolomite selectively replacer the 

black matrix dolastone. A Zone (Fig. 1.4). Scale in csntimtres. 

b. Stylolitea form boundaries between the bases of gray dolostme 

mttlea and underlying replacive saddle dolmitsa. Drill hole south of 

L Zone IFfg. 1.41. scale is 1 m. 

C. ~~eudobr-ia with abundant saddle dolomite. saddle dolmite fom 

cements peripheral to vugs (v). Extensive replacement leaves dirrenri- 

mted gray dolostone mttles, silica nodules (SiO., and residual 

dolostone along etyiolitea. P Zone (location, Pig. 1.4). Scale in 

cmtimetres. 

d. Pssudobrsccia with less than 25% saddle dolmite exhibits several 

typas of gray dolostone: (1) resistant light gray burow mottles (1.4). 

(2) gray matrix dolostone and (3) black matrix dolastone vhlch nay 

largely be gwpetsl. White eaddls dolmite swots subhorizontal pores 

and veinlets and selectively rephoes mtrix doloatones. C eone (Fig. 

1.4). kale in sentinetres.

. coarse spnrry dolostone matrix (gray) aggrades into negaorystallins, 

white saddle dolmite (arrow). Early dolaitized burmvs (black) sro 

relatively unaffedea. Bedding plane, Table Point coaetal section. 

Barter is 2.3 m in diameter. 

din

Plate 13.4 Replacement by Pseudobreccia 

a. saddle dolomite replaces mlds of gastropods (1.2). Lit* seddle 

llalonite locally fams eggreding fmnts with gray, m e sparry 

dolostone (2). Badding plane, Table Point masts1 section. Pen is 13 

om. 

b. Saddle dolomite replaces e gastropod mld 11). Resismt silica 

nodules (other arms) daminate mottles. Bedding plane, Table Point 

cwstsl sectim. PBn is 13 em.

13.3.2 cqetal T-s of PeeudDbncda 

.1) 1 

In general pseudobreccia oonsisto of gray, fine to medium crystal- 

line, realdue-rich dolostone and white, coarse, to megacrystillline 

saddle dolnnite. The grey dolostones are omprised of three texturally 

different cmmnenta. Oolomite v overprints finely crysteliine doio- 

stone (11, 111, lV1 mttles which originated during early burial. he 

result wears aa xenotopic, mdiu. (100 to 200 pl erystels with dull 

roa ffi of tmlonite V (P1. 5.5~). other cylindrical burrwe, ones fIllcd 

with coarse calcite, are raphd by dear, madim-sized (200 p ) 

ccystalr of Dolmite V (PI. 13.3a). The remaining gray to black 

dolostones betreen these early b ums end dolostone mttles originated 

as marse matrix dolostones (IV) and geopetal aedbmts deposited in 

ore-stsge prn (Pls. 5.5b.e; 12.2E; 13.la.d). Nedium to coarse (100 to 

500 IM) ewant crystals of Dolomite Y replaoe these carbonates. Black 

insolvble residues charactedstically acmr hstveen the xenotoplc to 

idiotopic crystale (PI. 5.Sd). 

white saddle doldtes amund the grey doloatones indude both 

cwnt and replitcement crystals (Pla. 5.5f; 13.3b,c.e). Saddle aoiolomits 

cements (A and B) dispsplay an increans in crystal size (200 pm to 1 m) 

as they progrsssively fill csntimetre-sized pores. The increase in 

crystal size is accompanied by a change in crystal habit ffrm pprimtic 

to -ant (P1. 5.5e). Crystal mntacts are generally planer. In 

mntrast, where saddle Dolomite A replacer a prscursor dolomite it form 

a naaalc of [loo to so0 p) irngnlar, xenotopic crystal. (Pi. 5.50,E). 

bundaries betwen cent and replament crystals ere vague because 

plane-edged, prislnati~ crystals penetrate 100 to 200 w inside residual

122 

~rqins of gray wttles (PI. 5.5f). hswainq that all euhedrel crystals 

filled open pores, m y paeudobressias contained 40 to 601 porosity 

prior to saddle dolomite precipitation (PI. 12.2Il. 

13.3.3 Mwral Psbric and Gemetru of PsevdobRccia Sodlee 

sadale dolmite seleetivsly replaces bodies of coarse lmtrix 

dolostone lmlcmite N) that originally were peloidel peckstones and 

greinstonea (Pig. 3.1). In the upper 40 to 60 metres of the Cata,ho 

Pomut~on approximately 30 beds of pseudobrescia, each 50 to 100 m 

thid, am interbedded with finely crystalline, gray dolostone beds 

varying in thickness lorn 20 to 100 cm (Pig. 3.1; 13.2). The gray 

dolortone beds crysteilizad eithor near surface as early fine dolostones 

(oulonite I) or during prs-ore epigenetic dolomitizetion (as colonrite 

N). 

Bodies of preudobreccia envelops ths isngth of fracture systems 

and extend 10's to 1000's of metres away f m fracturs zones into stmc- 

turally undisturkd stratigraphy. The fabric and geometry of pssuda- 

brecsia ohange outwards f m vein systems and bodies of early dolostone 

(such as rak-matrix breccia) (Pig. 13.2). In the vicinity of early 

dohtone bodies peeudobreocia occurs as sparse patches and veinlets of 

saddle doldte (termed mtchy pseudobreccia by exploration geologists 

st the mine). Within end around vein cnplexes abundant veins and spar 

breccias are edrosiated with 1-s solution pores. Here the charac- 

teristic even bedded, mttled fabric of preudobraccie (=-type of Coran, 

1982) becomes an irnqular fabric of crass-cuttire veins, sadale 

dolmite-filled cavities, breccias and patches end curved bands of

P~a~dobm~~lil Is widespread in the upper 50 m of the Catoche 

Farnution. Three main facier of pseudobreccia include (1) veined 

pseudobreccia with lrregulsr fabrics which occurs along fracture zones, 

(2) bedded pssudobreceia which replaces surrounding ereas without 

rtructvrnl disruption end (3) patohas of pseudobrecr?ia which partially 

replace mrgina of bodies of early dolostone. Coarse sparry dolostones 

war at the lateral transition inte limestones and at depth beneath 

stmtabound pseudobrecciss. The profile is ompiled frm a cross- 

section of the hng Hole Stope erea of the L Zone (Pigs. 10.2, 12.5). 

but it applies to mst ooarse dolostonel sphslerite bodies in the mine 

ama.

VARIATION OF PSEUDOBRECCIA GEOMETRY

madium Erystalline gray &lortonc. The bands and patches of precursor 

gcay dolostone are the result of dolonitination along pre-ore tmcturcs 

and suluti~n pores. This distinctive fom of psrudobreccia is temncd 

dilrvpted or d-type by comn (1982) (Fig. 13.2; Pi. 13.isI. Only 

47.5 

twtres away from fractures evenly bedded pseudobreccias have the Lyplcai 

vniform mottlea fabric d the E-type (Plats 13.lb). Toward limealone 

contacts decreasing mounts of saddle dolomite are irregularly dts- 

tributed between "lsyera" of cowse sparry dalosrone (V) (PI. 13.3b.e). 

13.3.4 Pabek E b n b of Pw&&xecoia Bsas 

coarse crystalline gay dolostonas becae paeudobreccias where 

they consist of mre then 10 par cent white saddle dolomite. Pseudo- 

beemlas, thus, range in appearance f m bcds with aillimetre-scale 

wisps of saddle dolmite to those dminated by white dolomite with 

isolated gray dolostone mottles, mnmanly tha percentage of saddle 

dolomite in a given pseudobreccia bed decreases away frm the middle of 

the bed (PI. l3.ls.b.f.h). PseudcQranias exhibit f ar different fabric 

elments: (1) normal (a-type) pssudobrsccia; (2) veins end mgapares; 

(3) rhythmic gray bands; and (4) breccia. (Pig. 13.3; PI. 13.1). 

(1) A-1 ~aeudobnccie mbrie - The mnst wmon and typical 

pseudobreccia faris is oanpossd of in relics of gray dolortone 

surmunded by white saddle dolomite which cements fomr nesbpares snd 

msgapores a d replaces grey dolortone along the interface with the 

ants. The relic gray dolostone UmttlesU exhihlt two aifierent 

gemtrier: (a) horizontal and (bl disseminated, irregular shapes vith 

no orientstion (Pig. 13.3, P1. 13.lb).

~igurr 13.3 Fabric Elements of Pseudobreccia 

Pseudobreccia beds mntein five main fabric elements. 

(illustrated cxmplen in Pla. 12.ls.d; 13.lb,c.d,g.h) 

(1) Horizontal mttles occur in the upper portions of most beds. 

(2) ~ottles e-nly ere disseminated and irregular shapes in the middle 

of beds. 

(3) veins cut gray dolostone interbeds and neme with macmres and 

sheet cavi~ies whlch m n l y =nu. in the middle to upper prtions of 

pseUdobmCcia beds. 

(4) s1ilgle dolostone bands are found bsnsath fomr cavities. Rhythmic 

dnlodtone bands ar. found in the lmer portion of pseudobreccia beds. 

(5) ~r'ragmenta of lninbis, pseudobreccia and gray bands locally fern 

breccias within wepores and along veins.

I 

FABRIC ELEMENTS OF PSEUDOBRECCIA BEDS 

1 HORIZONTAL MOTTLES 

2 DISSEMINATED MOTTLES 

3 VEINS AND MACROPORES 

FlNElUEDlUU 

GRAY DOLOSTONE 

4 RHYTHMIC AND SINGLE GRAY DOLOSTONE BANDS 

5 BRECCIAS

112R 

(1~) Amiuntal Grw Dolastme Wottles - Disanntimous, horizontal 

mottles, 1 to 2 m thick, characterize the upper portions of pseudo- 

brecoia beds (Pl. 13.lh). The prsfarred orientation reflects earlier 

bedding, horizontal burrnus and stylofabrio (Chapters 4,8)(P1. 13.3e). 

The original etyloresidues comnly persist end fom stylol~tic mt- 

tlelsaddle dolomite contacts (Pi. 13.3b.c). The regular, vertical 

spacing of horizontal mottles and gray dolastone layers is a secondary, 

epigenetic phenmna, however, which bears no relation to depositional 

fabrics (PI. 13.lf.g; 13.3h). 

(Ib) Dirmatd Grw Dolo~tons Mttlea - Equidimsnrionsl, evenly 

distributed mttlea rurmundsd by white saddle dolomite generally 

charaoterize the middle of pseudobreccia bed8 with nore than 40% saddle 

dolomils (Pl. 13.lg.h). at 1-t half of the saddle dolonita is cement. 

The remaining spar is nannorphie, replacing margins of gray doloatone 

mottles (PI. 5.50). This fabric also reflects the irregular distribu- 

tion of minor mounts of early dolostone in the original ploidsl 

grainatonen, cmpared to the abundant horizontal burrows in the vpper 

parts af beds. 

(2) veins and Me-es - Finely cryetalline gray dolostone 

strata intercalated with pssudobrsccia beds are uannnly broken and 

cross-out by saddle dolmite veins. These veins merge with the upper 

parts of pseudobreccia beds and effectively connsct irregular, subbri- 

zontal net-b of mcmpores (Pig 13.3, Plr. 10.la; l3.la; l).lc,d). 

The resulting channel and sheet pores extend laterally along horizons in 

the middle or upper third of pswdobrsccia bds (PI. 10.1). 

These veins and mgwms, previously mavated by ore-stage

429 

fluids, are reduced in pisc fmn original openings of 5 to 10 cm vide to 

present wys of 1 to 20 cm diameter by cmnt sequences of sphalerite, 

saddle dolomite (I and 8) and calcite (Pls. b.la; l3.ld). Megacrystals 

01 Saddle Dolanito B and calcite up to 20 cm in diameter occlude s- 

pores. Pores that reolain are c-nly ,'peppered" with fine marcasitc 

crystals which are ovemmvn by euhedral calcites and sulphatea. The 

saddle doloniter also lccally bear thin coatings of h-tite and 

Pymhitmsn. 

(3) Gray mlwtw man - On the walls of mine warkings the lower 

third of p~eudobraccis beds typically rontsin multiple or individual 

gray dolwtone bends areas-cuttins primary depositional fabrics (Pis. 

13.la.s.e.f.g; 13.1). Theee bands or patches comprise areas without 

saddle dolomite or solution pores (PI. 13.2b.d). Individual bands 

c-nly osnu below megcpores and adjacent to veins and faults (Pl. 

13.1s.d). me discontinttoms b&ds pinch end -11 in ectua~ thickness 

fmm It0 30 om and exhibit suspllte, lobete or "-shaped mrphologisa 

(Pig. 12.2; Pls. 13.1s; 13.2e). me oonvex danrards or undulating 

bends cmnly separate pawdobreccia with sulphides in the upper 

portions of beds f m underlying -ae dolostones containing only minor 

sphelerite (Figs. 12.1, 12.2; PI. 13.2a) and, in plaoes, minor saddle 

blonite (Pl. 13.1t). Sulphides above gray dolostone bsnds "pinch-wt" 

where bands rise to meet overlying finely crystalline dolostones. These 

"pinch-outs" are cnnnonly repeated in 3 or 4 successive pssudobressia 

beds (Fig. 12.1; P1. 13.2~). These relationships suggest that the 

dolostone bands impeded fluid movement during alphide deposition end 

addle dolomite ~stelllzation.

mltiple grly doloqtone bends ocsm as evenly spaced rhytbic 

430 

layers (2 to 5 cn thick) (Pls. 13.19: 13.2b,e,f). They are separated by 

3 to 6 11-thick layers of saddle dolomite andlor sulphidas (PI. 13.2 

d.f). The resulting striped appearance is variously deaaribed as "eebra 

rock" or "soontail rock" (s.9. Gcogan, 1949; Beales and Hardy, 1980; 

Devoto, 1985; Cowan et nl., 1905) and diagenetis crystalliration 

rllytbmite~ (m's of Pontebote and mtutz, 1983). At Danisl'a Harbaur 

4 to 7 repeatsd gray dolostone bands are c m n (PI. 13.2). and rarely 

exposed "cross-la~aring'~ ~ontains up to 25 rhythmic layers (Fig. 10.3). 

This febrls mimics p rhry horizontal stratification, smss-bedding and 

Stmatolites (Pls. 23.19; 13.2c.e). Three-dimensional euposures, 

~~WBYBI, r~v1.1 thst undulating bands cmss-cut prhry Pahric and 

snnnnly stscpen past the angle of repoae. Individual bands are 

discontinuout, and they either end abruptly, bifurcate, or mrge with 

other bands. They are m n l y truncated by overlying gray bloatone 

bands (Pig. 13.2). Most rhythmic layers are associated d th cmer- 

cutting veins end faults. They sona~nly nre inclined darn toward veins, 

where they merge with steeply inclined bands of thick gray dolostone 

(Fig. 13.2: PI. 13.1s). Rhythmic layering is also well developed in 

psoudohrecias along fnuite where the baas abut finely crystalline 

dolostone strata (~1. 13.20). These features Imply thst the bands 

develoyed on a fractured and faulted f-mrk. 

In deteil the gray dolwtonc layers with the primary mottled 

fabric of pre-ore doloetone~ have plane bases and irregular tops dwply 

indented by replesive saddle dolomite (PI. i3.2d). Planar besea which 

sre nearly coincident vith stylolitss ere mildly indented and replaced 

'

431 

by saddle dolaoite. l'hs.grsy dolostme bands ere m n l y black to dark 

grey. These black dolostones IV) includes presursor early mttles 

l11,IIIl end mtriX dolostone (IV) (PI. 13.26). Abundant block inter 

crystalline mat-ial and vagve fragments suggest a m dissolution in 

these layers. The intercrystalline material Ir mrnposed wstly of day 

minerals; organic matter oonstitutcr only 0.301 to 0.9m of the rack 

(Rppenaix 8). 

Cementad sheet cavities comnly =cur between gray dolortone 

layers. Sequences of rphnlerite, geapetal sediment end saddle dolmite 

(1 and 8) locslly fill these oavi(Pie8 (PI. 13.2E). In most Places, 

howeve?, saddle dolomite is the only cement and grades into replaserent 

spar In the upper portions of the grey l e v (Pl. 13.2d). Hhere 

cemented sheet cavities are absent saddle dolmite selectively replaces 

light gray layers of precursor dolostone between the darker bends (PI. 

I3.2b). In all emplas Saddle Wlmito A cements veins which a t a11 

features. 

This sslllsstive evidence indicates that rhythmic layering fo& 

in assmiation with frilctules during a pre-ore event, pmbably at the 

tine of type XV dolmitlrstion. selective dislolution of intercalated 

carbonates Eorned sheet cavities prior to aulphide deposition. hlring 

poat-ora dolanitization (V) grey dolostones recrystallized a. Sadrile 

Dolmlte Pi occluded late veins and sheet oevities, and partially 

teplaoed and obliterated the earlier fabrics. 

(4) - Displaced and rotated fragnents are loselly inmr- 

pomted into pseudobncda beds (Pls. 7.3, 10.1, 13.le). These breccia= 

are associated with cross-cutting =ins end fractures and cmnt-reduced

mgapores. Varieties of breccia, in order of abundance, include: (I) 

disrupted gray dolortons bands (PI. 13.la); (2) ftagmnted gray dolos- 

tone along veins IPls. 10.1, 13.lh); (3) collap6sJ fragments of overly- 

ing tine dalostone beds (Pls. 7.3, 10.lbI; and 14) wholesale micmErac- 

Lured and fragmented pmcurror dolortona, usually along faults (Pi. 

417 

7.34. As noted in the description of spar brassisa (Section 11.4) most 

trap~nts rain nearly in plaoaoe 8s rnsaic brsccisa aeperated by saddle 

do1rmite cenent. 

13.3.5 1nterpntati.m QC -Lo 

The =-site fabrics and textures uE pseudobresoia famed thmugh 

six or mra episodes (smmrized in four stages in Fig. 13.4): (1) early 

burial doloolitieation (11,111) d atylo-mttles (described in Chapter 

8); (2) pervasive pre-ore 9igenetid dolrmitieation (IVI ot limestone 

matrix to coarse matrix dolostone (Chapter 11); (31 fracturing end 

selective solution of this mtrix doloatone imdistely preseding ore 

deposition; 14) owntation in pores and partial replaomant by 

rphalerits (chapter 12); (5) frnrturing and solution of sphalerites and 

aolostones (clearly seen in PIS. 10.lc. 12.2e); end (6) cementation of 

pores and partial replacement by Saddle Dolomite A while pervasive 

dolamitizatian IV) rewstallized the cmant gray doloatone IPls. 5.5~; 

n.3c,d,e). 

Duriw post-ore doloaitization hydrothem1 fluids migrated along 

vein systms just as previous ore fluids had done. Fluid fln, solntion 

and owntation faused around veins and mscmporas and *as Eonfined 

betwoen gray dolostone bands. Fluids dltfused outwards tens to hundred.

igurc 13.1 Evolution of Pseudobreccla 

a. Early Burial mlwtone - Early dolmitiastion (I, TI, 111) repla~ed 

rcritidal mudstones uith stratigraphic dolostones, formed ubiquitous 

dolostone lmttles in limestonas end converted ewiy fault zones and 

rock-mtrir breccias into discordant doloatone bodies. 

b. Psmasive Pn- Dolodone - Dolmitlzstion (IV) replaced lhstones 

with coarse matrix dolostone adjacent to early epigenetic fractures. 

These dolostones overprinted early dolostone mttlar. 

E. P~C~W~DIJ, DIQBOI~~~~ and ~phids ~eposition - ore-st- fractures 

cut both early burial and pre-ore doloetones. Selective diaaolutlan of 

coarse matrix dolostone I linestone beds pmduced sheet cavities and 

honeycomb networks of mesopoms. Sphalerite canented the rims of these 

pores and partially replaced the dolostone. Geopetal sediments covered 

the aulphide crystals. 

d. Pemaaiw Post- 010~1008 - extensive dolmitiaatian follow& 

post-ure fracturing. Saddle dolomite cwnted and olosed mch of the 

pore space. Saddle Bolanites also replaced coarse matrix dolostones to 

form peeudobreccia fabric with relic islands of gray dolostons and as 

much as BO % saddle dolomite.

.UTION OF PSEUDOBREC

435 

nf tletrea thmugh adarae gray do1ostone beds and tranafornled then to the 

characteristic narttled pseudobreccia fabric. Evl~edrol prismatic 

megauystalline saddle dolonites emented mesopores whereas nwmrphic 

crystals developed intargmwn xenotopic boundaries. Elevated pare Iluid 

pressures ()hydmstatis pressure) probably supported bsds with abundant 

open pores vhile marre crystalls slowly precipitated. Abundant stylo- 

lites at gray dolostona/saddle dolmite contacts attest to the burial 

nature of this dolmitizetion. Hinor variation in W, end fluid chenis- 

W left uniformly lurninement dolostones, characteristic of deep burial 

dolnnitizetion (Lee end Friedmsn, 1987). 

Theories of Orisin - "Diagenetic rhythmites" or zebra mcks are 

puzzling features and so have been the subject of seven or more inter- 

pretatiws. 

(1) Layering in .me instances follows sedimentary strstifisatiw 

of prinery bedding (Samaniego, 1982) or secondary cavity flll~ (Cowan et 

nl., 19851. Similar fabrica occur in layered Stranstactis, also called 

zebra linestonen. In Strmatactis, calcite semants and geopetal 

aedinent fill oavitier that develop by erosion or solution of "unmn- 

solihted" lime mdd between early cemsnted crusts or organically hund 

layers (BaUlurst, 1980. 1982; Pratt, 1982). 

(2) Intercalated sulphates end carbnates typical of supratidal 

and other hypersaline sequences also evolve into rhythmic layers. 

expension d layers and nodules of anhydrite during the mineral trans-

formation to gypsum hrther separates carbonate beds. Deformtion 

during this transbmtion pmduces chicken-wire fabrics and frynenta- 

tion of surrounding carbonates (Bosellini and Hardia, 1973). Pseudo- 

breccia fabrias suggest these features (Beales and Hardy. 1980; Colon, 

1982). Selective dissolution of rulphates by waters undersaturated in 

,116 

so.-" generates shet cavitiaa. Sulphatea tend to be dissolved by Eresh 

water sither (1) in early stages of sedimentation 1e.g. Wicia, 1972) or 

(2) in later history. in near surface portions of basins (e.9. Sando, 

1967). 

(3) Dilation of brittle mck -only opens fmilier of subparal- 

lel fractures. The mst familiar of such fractures are en echelon 

tension gashes which fom at an angle in zones of simple shear (Rmsey, 

1961). Typical inclined rhythis layering mimics this fracture pattern. 

(4) Selective dolmititiration along fra0tu1.e~ and Styiolites [my 

form 1.~111 dolostwas resistant to later ai~aolution and replaoenrent by 

saddle dolmite. Although stylolites are plentiful in limrtoner, a 

regular distribution of stylolitea and stylmttlar characteristic of 

rllythmites is not present. 

15) Fontbate end mstutz (1983) identified these teaturas aa 

"diagenetic crystalli8ation rhytimites", recognizing that mat aspects 

of the dcl~stane layers are diagenetic and display features similar to 

those thought to fom by ciagenetic crystallieation (Fontbote and 

mtutz, 1983). Their peridicity 18 considered too regular to be 

sedimentary. In theory, king a process of fractional srystalliration 

minerals were segregated into three generations: (1) starting sheets ol 

gny dolostones; (21 bipolar subhedrel wts-rim cements; and (3)

woluding pore-centre cements. 

nn 

(61 D~lostOne bands my also forn at the bovndary d two fluids in 

a pamus medium. Single- ena mnltlple-preci~ltare bands of organic 

mtter in uraniun-roll front depwits have a conparable lmrphology to 

cuspate, lobate this dolmite bends. Heridue-rich organic layers would 

be potential sites of aelectivs dolomitizstion. In laboretory experi- 

ments Ethridge et al. (1980) modelled the dwelopant of organic bands 

at the interface of two fluids in a parnus sandy media in the labors- 

tory. Organic mtter precipitates during a dmp in pH at the bundary 

of tw fluids. Is rates of fluid flow change, a rising fluid boundary 

leaves below multiple bands of organic precipitate. Descending fluids 

dissolve or flush out the organics. This process has the capability of 

prcducinq simile or multiple bands which cross-cut sedinenteq Eabrlc 

and which =an be "dissolved" by subsequent fluid fmnts and truncated by 

their respective deposits. The lobete and cuspate fam of Eluid 

bxlndaries can be produced by irregular displacenent between two 

lnoniscible fluids, flow eddies, gravitational descent of a heavier upper 

fluid into a lighter undsrlying one and deflstion of the bundary 

cicross prhary mdstane lenses. 

(7) Double diffusion convection between two fluids of different 

temperature and salinity is ewloyed to explain layering of fluids in 

mean water, m.9m chmbsrs and porwn media Imrner and Chen, 1974; 

Tarner 1974, 1985; Griffitha, 19791. Tamer IW4, 1985). Criffiths 

(1979) and others denonstrate that mltiple auh'orirantsl diffusion 

boundary layers develop in a fluid when a v m brine is plased under- 

neath or alongside a mler brine with different salinity. The leysr

oundaries, or dens

open dur~ng the four'stage precipitation of aphalerite, geopetal 

sediment and Saddle Dolomites R and 8. 

(5) Bvidence presented in Chapter I2 suggests aliochthonous, 

metal-bearing, hydrothermal fluids rose f m deep in the sedimentdry 

pile and pmbsbiy displaced formational waters in the upper Ultoclle 

Pomtio~:. 

,139 

- Based on the foregoing constraiqts, the lollwirm hypo- 

thesis is suggssted for the origin of the dolostons bands. The bands 

were ere-ore spigsnetic dolastones which fonned subsequent to fracturing 

and during continued deformation. Wun fluids risiw Crm derp in the 

sedimentary pile travsled along vain. and faults. and encountered cmler 

brines in adjacsnt beds. The nore buoyant wen fluids displaced the 

lwal, tomtional brines in the upper, permable portions of beds. 

Multiple density layers developed at the fhid boundaries as the brine 

cmled and nixed with the resident fluid by double diffusion. The 

statio density layers bscme sites of residue concentration. Fluctu- 

ations in relative supply and volume of the tw Fluids altered their 

bmndaries. The shifting fluids dissolved or flushed scrw residue 

layem and truncated others with new deposits of residue. . 

Hajor fracturing and dissolution arrested +his pro;ess as the 

obipitous resopores and cavities of pseudob~wcias tomd. The 

frameuork of dolortone bands reslstsd dissolution and fomd dividing 

Mnkier of low permability between sheet pores and mrse &loatone 

Wies of variable porosity. Subsequent metal-bearzng brines and later 

%lomitiring fluiaa were funnellea hetween dolostone bands, with the ore

fluid nsually confided to the upper portions of bad.. It is unknam 

whether gray bands developed further during mineralization. The 

dolmtone bands were nsomrphosed during post-ore dolonitUation hut 

resisted saddle dolmite replacement. The sheet pores gradually filled 

ulth pxecipitates of sphalerite, gsopetal sediments and saddle dolonite. 

Naintenance of multiple sheet pores over the duration of sulphide and 

dolmite precipitation rewired support by pore fluids near lithostatis 

presswe. 

13.4.1 Distrmtiw 

The tern spar bmsia is assigred to framented dolo~toneo 

i40 

emoted by white saddle dolmitr. such spar breccia. are cmmn in the 

soarhe dolestone cmplexss of the uppsr Catoche Porntion, and are also 

scattered thmnghout the Aguathuna Porntion, the upper portions of 

mck-mtrix brecias end, lceally, in the lover TDble Point Fomtion. 

five types: 

The style and distribution ol spar breccia can be resolved into 

(1) Ll- Rmture Zms - The mst m n and Mportant spar 

breocias are the ore-bearing stratabntnd vein systems 10 to 30 m thick 

by 20 to 60 n vide by 1000's of metres long. veins fracture biitile 

finely smtalline gray dolostones in theee systems. Dolostonrs between 

veins are bmken into mais "fitted" fabrics and emented by saddle 

doldte (PI. 10.1:. mst of these veins do not pnetrate intercalated

1.11 

paeudobrec~ia beds, Which also contain mnor breccia Iragonts. Phc feu 

veills which cross-cut pseudobreccia beds are enlarged hy dir~oitlliort and 

mms with subhorizontal cemsnt-filled cavities (el. 10.1a). Fragnien~r 

of overlying gray dolostones c mniy fill these veins end cavities ($81. 

10.ib). These vein-brxsias are cmmn in densely fractured ronew. 

Spar breccia. locally incorporate rotated blocks a! pseudobreccia along 

north-south cl.0~~-fractures, the mth sides of main trend fracture 

'zones and in the North L Zone (Pls. 1.3b. 13.5~). 

(2) Breccia Associated with Widemread Pmdohnccie - Brittle 

finely crystalline gray dolostone beds between pseudobreccia beds arc 

mildly fractured end breccieted away frm fracture zones. P~avdobreccia 

beds are locally internally brecclated as described in the previous 

ssction. 

(3) -1 Swr Breccia Ediw - large dm1 spar breccias ere 

rare at Daniel's Harbour. The long Hole Stope of the L Zone is a 

brecclir body 30 m high by 60 m vide by 300 m long. Outward dipping 

veins et the top of the breccia suggest d m1 collapse (Fig. 12.h). 

Several d m1 brecclas with spar matrix are also well exposed along Lha 

coast it0 5 loo north of Table Point in thm Deer cove-Bateau Cove area. 

B~BCC~~B In this area wre described by mron (1982) and Knight (1986). 

There 50 m wide by 30 m hlgh breccias are distributed along a linear 

rose of vertical spar veins which parallel a fault zone. saddle 

dolanrite partially replaces fine rock matrix In s m of the brrcsiar. 

Dmal spr brescias, or collapse brescias with coarse m-k- 

mtrix. ~ L comma B in east and central Tennessee. They vary in size 

fm small linear V-shaped structures. 5 n by 5 m, to large dams 30 to

Plate 13.5 Spar Breccias 

a. splinter-type *per breccia in a finely crystalline dolostone bed. 

The brittle do:ustone ha. broken into e series of splintera and angular 

fragments. Palisades of white saddle dolmite cement an expanded volume 

of rock leaving scattered wgs. Sample f m fracture% gray doloatone 

interbed in the F Zone (looation map, Fig. 1.1). Similar breccias seen 

in PI. 10.1. 5501~ in centimtres. 

b. saddle dolomite (at the left) replaces mtrix of e mck-mtrix 

breccia which is preserved at the right. CathodolMneacent petrography 

Indicates that Lhe mtrh was nmorphosed by pa=t-ore (V) dolmitiae- 

tion. a coarse dolostone/sphalerite oaaplax intersects a rock-mtrh 

b,reccia at n cross-fault in the L Zone (locaton mp, Fig. 1.4). Scals 

1s 10 m. 

c. a lo m by 10 n breccia body Fm the North L Zone. Finely crystal- 

line doloatone beds are cleaved into 10 to 100 on-wide fragmnts along 

the s m synclinal fold and reverbe fault Indicated in Pig. 10.7 and P1. 

10.lb. Fragments at the top of the strvctum rmin in sit", others a n 

displaced up and down relative to each other and scne are collapsed into 

e lvbbla breccia in the centre. North L Zone (location map, Figs. 1.4, 

10.7). Scale 1s 2 n.

lw metres in diarnetm by M to 50 m in height (ilcCamick ct ai., !971: 

Gaylord and Briskey, 1983). It ie unclear what percentage of the 

stmctllle~ is early karst breccia, but late saddle dolomite matrix 1s 

widesprsed. Thebe d m1 stneturea characteristi0aily have internally 

broken and collapsed rtrotigrephy. Hoseic aod crackle breccias, 

.:I.\ 

fractures and veins cut peripheral strata. veins end faults surrounding 

the reccias tend to dip outward. 

(4) Altered minm or RoeL-Hatrill Breccia. - Saddle dolomite 

SelestiYely replaces the matrlv of rock-matrix brmcias emund margins 

of these older bodies. Replaced breccias occur at Deer Mve, the large 

crass-fracture of the vest L Zone and in the North L Zone. The frag- 

mnts are distinctly oligmictis to polpictic and nan-fitted. Highly 

variable sizes and shapes include abundant centbtre-sized clasts (pi, 

7.3d). met rspleced breccias contain relict patches fine rock-watrix 

IP1 13.5b). 

(5) Veined m s of ~ILatri. Brecsiss - Saddle dolmite clanents 

networks of veins and msais brsccier in the wusthuna Fomtion above 

dolmitized md-filled rmk-mtrh brecciar in the Catoche Formtion. 

13.4.2 Int-tation 

The charasteristios of spar brecsias are key to their interprets- 

tian. (1) The breccias are ohiefly mseiss of the original rock with 

gaps (one-fifth to one-quarter volume) cemented by saddie 4dianite (el. 

10.lb). The fr-nta are not in clast support. (2) Crystals have 

grwn into central votds from fracture walls. (3) Gravity oollaprea 

fregnents & not acNnulete in rubble heaps but instsad, appear suspend-

ed in saddle dalmite. near the original site of formation and arc ouly 

1l4'i 

slightly displaced (PI. 10.lb.c). (I) Finely crystalline dolostonoa are 

brittlely fractured into small elongate =lasts (Pls. 10.1~. 13.56). 

These spalled slivers are m n l y incorparated into the saddle dolomite 

cement. 

At least 6 tmdels potentially explain the brecclation: 

(1) 

(2) 

(3) 

Collapse and fractare related to intrastratrtl solution: 

Defamation during enhydrite-gypm transfomtion and later 

evqporite replacement by saddle dolmite; 

Replacerent of matrix oE narlier rack-matrix breccia; 

:4) Tectonic fracturing; 

(5) Fracturing and vein crystallization under elevated Fluid 

pressure and hydraulic fracturing; and 

(6) Fragmentation fmm temperature and chemica? changer - "chemical 

brecciation". 

Evidence for mst of these processes is present. Evaporite replacement 

is considered unlikely, however, becauae preovrsor sedimntary 

litholqiea of the upper Catoohe Pornation lack evidence of depositional 

evaporiten (sea Chapter 3). The problem here is to find a unifying 

process which explains the cabination of features. The breccia fabric 

and vein gmetry is Interpreted to be the result OF tectonically 

dire~ted smpresslon at elevated flnid pressures. The distinctive 

reparation of mssic fragments by pore-filling saddle dalmlte indicates 

that breccia fra-ts were suspended end cenented in a fluid-fllled 

pores. mesa conditions could have baen satisfied only if pars fluid 

pressure equalled or exceeded lithostatis pressure 1e.g. Ofe et el.,

19191. Flllld pmasure could have built up beneath lo* pemrahi1il.y 

J.lh 

barriers, such aa thc Aguathuna Formation end fine dolo~tonc beds of he 

Catmhs Porntion. 

Rrecciation aod cementation occurred in m e Lhtls Civa dlscretc 

stager: tm epimer of bresciation Collawed by prccipltatlon of 

multiple ieyers or sphaleritc (PL. 6.W; brecclation of rphelerilc ilnd 

gray dolostone prior to cementation by Saddle blomite L (pis. 10.l~; 

12.2~); and rupture of veins end rehealing by Saddle Dolaaite 8 around 

frawnts of sphalerite and Saddle 010nite R (PI. 6.la.e). These 

repeated cycler d cementation and rupture characterize the evolution of 

Pore fluids in s- sedinebtary baains (e.9. Pyfe ~t sl., lT19). ma 

crack-seal mechanism of hydraulic fracturing mcurs vhan impervious 

strata cause a build-up of pore fluid pressure, brwciation releaser Lhe 

Pressure and cementation of veins leads to another cycle of increased 

Pressure and rupture (Hubbert and Wlllis, 1957; Phillips, 1972). 

Splintering of well mck ba erplained by brittle failure en-iatd 

with hydraulic fracturing along mltipie fractures on the margins of 

veins, rather than by sW1e grsvitatimal mllapre. 

R drawback of the hydraulic fracturing mdel is the observed 

sepratioa of splinter breccias by saddle *lomite cwents (Pls. 10.1~; 

13.Sal. mls wttern suggests that frawnts remained suspended after 

fracturing and h s mt exhiblt evidence of pressure release and 

collapse after hydraulic fracturing. 

Fluid pressure-induced breccia., hwever, were probably part of a 

larger systm of mientea veins ana fracture zones related to regional 

tectonics (Chapter 10). The tectonically generated systm of fractures

&am the conduit within which elevated fluid pressures produced the 

,Id 1 

expanhional breccia.. Although tectonic compression pmduced mnristant 

vein orientations the sporadic distribution of "sins in clusters 

probably fo-d during local uprard ~mpagation of pressuri~er! lluids 

(Pig. 10.6; PI. 10.la). 

The CUriouJ stratabound nature of veins and brsciss implies one 

or several styles of deformation. (1) Dissolution withi!) pseudobrcccla 

strata could tave generated gravitational milapse. This hypothesis is 

suppocted by lwal thinning of paeudobrecclas beds and disruption of 

grey dolostone strata over areas of maximum dissoiution in zones of 

mineralization and abundant saddle dolemite. (a1 Fluid "sills" local- 

ized along fracture zones and porous beds and canfined by impervious 

finely crystalline gray dolosbnes could have expanded uolwtrleally as 

fluid pressure increased (Qfe st al., 1979). The doiostones would have 

ruptured both by hydraulic fracturing and by subsequent collapse as 

fluids ware released. (3) The principal control on stratabaund veins 

MS probably tectonic defomtim, however. The oriented g-try of 

veins and their spatial association with faults and cometent dolostone 

bodies (described In Chapter 10; Pig. 10.8) reflects regional defama- 

tion as the causal mechanism. Oiaaolution and pore fluid pressure arc 

oonsidered to have been $ortent, but seoondary. 

13.5.1 DesmIpUm and Distribution 

krse sparmy dolostones IV) mcur at the lateral transition

1.10 

betwoen pseudobreccia and limestone end es separate bodies rurmnded by 

limestone (Pigs. 7.1. 9.1). Their gemctry varies significantly E~rnn 

Btcatabound bedr 5 to 250 m wide to discardant Wies which penetrate 

the entire Catoohe Formtian. They ere equigranular mrsics of mdim 

tu onrrae-sized, euhedral to subhedral rhonbs that havs replaced 

original lh#rstonss end retained residues of prmry hurm-mottled and 

psloidal te,:tures (Pls. 5.7a.b; 13.3e). Extensive intemrystalline 

p~osity is mmnly uncenrented, but in sn* places crystals are 

iokrgmuo (P1. 5.1c,d). Coarse crystals dsfirle areas of "mtrix" 

bet-" fine to mdim crystalline dolostone mttles (Pls. 5.7b; 

13.3b.e). Dolomite re ooverprinte precursor dolortones (11,111) in tile 

mottlcs. In ams caras an qnigranular maic of nrdiwn to cosrse 

crystals werprlnts a11 primmy fabrics (PI. 5.11). Phis is the s m 

lithology described as Pervasive B dolostons by Haywick (1986). 

nlthough marse sparry dolostones can be defined as a distinstive 

nappable facie., their distinction fm coarse matrix dolastones of 

pseudobreccia facie. is not clear leg. P1. 13.30). 

11.5.2 1atezpmtatic.n 

The laterally extensive coarse sperq dolostones origineted during 

Pervasive post-ore dolmitization (V) when fluids emanating frm vein 

-1exes pareed through pomus pre-ore dolostonc bodies into limes- 

tones. Coarse dolwitas (V) overprinted early dolostone (81.111) 

Dttlea and insqletely replaced the limestone matrix. Later dlasolu- 

tion of the remining limestone produced the ubiqitous centhtre-sized 

InlPS.

13.6 Diswrdant Gray Ooiosrones 

13.6.1 Deseriflion and Distr3htion 

isc cord ant bodies beneath vain -1exes arc narra*, 10 to 10 m 

wide, laterally discontinuous along the strike of main Lrend fualLs, ilrld 

undeilie most croaa-faults. Limited drill hole infornation suggenls Lhc 

g-etry of vertical bodies is cylindrical endlor clongato and tebviar 

(Pig. 8.2). 

The fine to rnadiu. crystalline gray dolostones possess only minor 

white saddle dolmita. early burial Dolmites I1 and 111 mcvr pcrva- 

slvely in these dolostones (Chapter 61. Anong the bodies ol discordant 

early dolostone, those beneeth vein cwlexes are affected by up to I 

rpigenetio events: (1) pervasive oeomrphim by pre-ors Doimite IV; 

(2) mimr frectuiirq and dissolution; (3) scattered precipitation of 

minor pyrite and sphalerite in intcrcryrteliine pee; and (4) varying 

styles of post-ore dolmitieation (V) em. (a) cementation of pores 

between earlier crystals (PI. 5.lf) to (b) precipitation of coarse 

crystals ic veiniatt; and mesopores to Is) losal pervasive replsccment. 

Thin beds of pseudobreccia and veinietr of white saddle doimite are 

minor. Deep doiostone bodies along the margins of mck- rnatrix breccia 

bodies are not altered by these cpigenctic phases. 

13.6.2 IntarPEWWCim 

Deep fractures and faults served as ve-risai fluid conduits for 

early burial and epigenetic daimitizetion (Dimiter I1 thmugh VI). 

Fluids migrated up lacalizad chmey to tabular-shaped doiostone or

trosture conduits adjacent to reactivated Faults. Lrt~slly Lo cm- 

4..n 

pletely dolcmitizcd'early badies were peevasiuely recrystsilized by pre- 

ore mlwnits Iv. Subsequent fracturing and dissulution created,pores 

*hich were omanted by laediow to Wrae, port-ore dolmitcs Iv,vr). 

P8BUbbZe~ciB and pervasive gray dolostone locally iomd within porous 

horizons and along highly fractured zones. a;clt!sian oE the prwiairly 

ubiquitous porosity by mlmites V and VI effectively sealed the 

do lo stone^. 

W.7.1 Description md Distribution 

Bodies of fine to coarse crystalline dolostone replace limestones 

OE the Catoche aind Table Point Farmations peripheral to asst of the 

major faults related to the uplift of the Long Range fnlier (Pigs. 8.2. 

9.4). These dolostone bodies range in width frm 30 m up to a kilonetre 

at intersections of mjor faults. The Lining of dolmitizetion is 

considered to be coeval wilh or following regional uplift besue the 

dolostoner are developed along the latest faults and they overprint 

stylolites. Wide ranging 6'"o valves of the dolostones suggest that 

they famed during severel events. Iacal distribution of sne doiostones 

abwe thrust faults imply that - dolomitizetion occurrad 

during syntectonic fluid migration along those faults (Pig. 13.5). 

In typical dolostones in the Catoche Pornation lmaaiss of euhedrel 

to subhedrs.1 rharbn with intercrystalline pomaity &nd unifonn red- 

orange ffi overprint depositional fabdss (PI. 5.7d.f). The fine to

,?eLiiu. crystalline dolo.t"nes are difficult Lo dis1inguish frn. older 

,151 

cornrue sparry do1oat;ner (V) which have dull red CL and interctyatalllr~c 

Dolomite VI cenent (PI. 6.19). Late sildle dolomite ("11) and lu8llncs- 

cent cal~its cement veins along faults. 

Late fault-related dolnstoncs in the Table Head (imup are di,itlnc- 

tirely very fine to fine crystalline and uoatller buff to tan colourn. 

This appearance has lead lo the supposition that these lithologiea might 

be Eacier-specific, early supratidal dolostones Caron. 1982). Thls 

doloetone, horever, werprinta all sedimentary facies identllied in 

linastone sections. Bright red CL overprints stylalitea and scoondary 

pores occur selectively along Eomc rtyiolites r7.d caarsc calcite 

csnents. This secondary porosity is partially cented by saddle 

dolomite (vII) and late luminescent cstsltr. 


Middle Paleozoic uplift of the Long Range Inller fractured and 

faulted the platform and displaced coarse dolartone/sphalsritc can- 

plrxer. over a protracted history fluids migrated along Eaults and 

dolomitized tens of metres into Catoshe and able point Imstanc:. 

Inter- crystalline ares and solution mesqmree vsre subsequently 

tenanted by saddle dolomite and late lminsseent calcite.

8~guro 13.5 Lalc Galmitization (YII) Along a Thrust Fault 

~crvarive late dolostones (VII) in the Table Point Fomtion 3 h 

LUUL~HBLL 0C the T Zone are dinirlbutsd throughout the hanging well of s 

thrust lauit %one (omas-tistion constructed fmm e detailed fence of 

drill holes). The hult steepens as it passes thmugh the St. George 

Gmup where it displaces a mar- dolostone cmplsx. Lacslization of 

doiomita ve?na along the fault indicates thst the structure affected 

earlier fracturing end dolomithation. 

There relationships suggest that dolanitization was syntec- 

tonic. The fault may have acted as en inrperuious barrier and/or 

pmvided a pathway for upward migration of fluids.

13.8.1 mmoriptim 

Potassium fermcyenide staining for imn, together with trace 

element and oxygen isotope analyses, differentiate otherwise lnwnagcnoul 

dolostone bodies or fades. Saddle dolom~tes with 2000 to 6000 ppm 

total Pe are locslized to lower parts of ooarse doloatone bodies, deep 

discordant dulostanes and rme coarse =parry dolostones on the wter 

elklea of cwlexea. Late dolmite cements, the latest zones uE Wlosxite 

V and Dolomite VI, are also Eerroen. S m saddle dolmite veins along 

faults in mck-matrix braccias arr sumnded by oxidation rim. 

Oxygen is~topss distinguish different dolmlte stegea as docu- 

wanted in Chapter 5. Om-dage saddle dolomite ia tightly constrained 

with 6'*0 values which range bstveen -9.3 and -10.8 oloo. Pure cements 

in veins and lnasopores are confined to a mall field betwean -10 and - 

10.8 o/w (Pig. 5.6, App~ppandix I). mls deta corteawnds to the field 

for saddle dolailtss eire~here in the Northern Peninsula saddle 

dolmitea (Haywick, 1981). addle dolomite outside ore zones have bath 

heavier, -9.3 to 6.7 olw, and iigbter, -11 to -12 olm, 6'"O valuos 

(rig. 5.6; ~ppendix A). one coarse rpsrry dolostone of Dolomite v stage 

has -7.7 do0 6'"o. Saddle dolomite veins within mck-matrix breccia8 

and the Teble mint Porntion ere particularly enriched. -6.8 to -7.0 

dm. In mntrast to the limited range of values for nast saddle 

dolmitas, samples €ram lab Eanlt-related dolostones have a wide 

ranging isu- topic sonpsitian -5 to -13 olw 6'"O PDB (Coron, 1982) 

(Fig. 5.6).

13.8.2 Intqzetstim 

Ssddle doldter in vein cmplexes prcclpiteted from hydrothaml 

hypersaline fluids. The light isotopic signature oE hydrothermal 

dolmite le boat represented by c-nt orystsls in veins. hs fluldr 

.IT,!; 

migrated laterally away frm "ern compicuer;, crystals precipitating ftm 

cooler fluids contained enriched 6'"O. Thls same cmling trand occtlrr- 

ed in the transition of crystellleation of saddle ~ololoiter h and 8 

(Chapter 5). nltsmatlvely, hydrothermal fluids ~ould havc gamed 

Incrsassd '"a by (1) dxing vith rallne fomalionel fluids vith high 

initial '"0 or by (2) reacting vith dolostones with heavy 6'*0 valuss. 

Iron-snriched saddle dolomites probably prooxpitatad from reduced 

(?) pore waters an the lover and outer extremities of cwlexes end 

throughout the cwlexee during late cryatalliretion. Haters whish 

reachad theae areas had been depicted in dissolved oxygen by several 

possible processes: (1) organic or hydrocarbon oxidation; (21 bacterial 

(3) rulphate reduotion; and (4) Inn oxidation to lorn 

hmtite. Oxidation rims on veins alow faults suggest that mlatively 

oxidized fluids migrated along theae structures. 

ate Ieult-related dolastones cry?rallized from fluids with 

various ca~poslC1o~s of metsoris wstsr and fomatianal brine. These 

fluid sources cmnicated alow the faults. The ride rahge of crystal 

6'"a reflects the varying inEluence al these sowses.

post-ore dolc@itization occurred in two separnte evants: .(I) 

Post-Ore Stage I, closely relatad to sphalacito deposition, rhcn finid 

temperatures ware arer 10o°C; and (2) Post-ore Stage I1 during and after 

regional uplift. 

P'mt-me Stam 1- Following extensive regional Eractcring at the 

end of su1p:hide deposition, fluids initially dissolved auiphidc cryntal 

facer, then saddle Dolomite Pl precipitated. The fluids Iollned 

vertical and subhorizontal pathways: migrating up local porous discar- 

danl doloatonas; fleving horizontally along vein complexes; and penred- 

ing coarse dolortone beas as far as 1000 m from vein conptexes. saddle 

dolmite crystallized locally within and around veins and cavities. In 

bedded sections of pseudobreceia, saddle dolomite unifomly cemented 

~~SOPOLBS and replaced mars. gray matrix dolostone. Beyond sslnplsxes 

of pre-ore dolostone, m s a sparry dolostone replaced limestone. 

Perm dolcmites with heavy 6'"O values in the lassr and outer ex- 

tremities of coarse dolostone cowlexes crystallized Erm -lor and 

mre reduced fluids than i n velnad centres. 

Pore fluid pressure approached lithoatatic pressure, and in 

cmbinetion with tectonic dilation, maintained extensive openings in 

veins, breccias and solution pores. Masah spar breccia* and coarse 

dolostones with mre than 401 w mdty did not mllqeae. Hydraulic 

rractvring occurred Lnnediately prior to the precipitation of bath 

Saddle Dolomite A and 6. Tha sudden release of pore pressure and spread 

of fluid into new fractures may have partially ccased precipitation of

saddle dolomite. 

Discoldant gray dolortone bands and eebra fabrics developed near 

fracturas in coerse dolostones during pre-ore dolmilization. The 

distinotive zebra fabrics probably fomed by dovble diffusion at mixing 

boundaries betusen hydmthenaal fluids and oooler formstional brines. 

The psition of there residue-rich layers mnaLrained letsr events aa 

disaolvtion occurred between laysrs end sulphides and saddie dolomite 

precipitated in singular and multiple sheet cavities. During ora-stage 

4 7 

and post-ore c-ntation. the thinly layered framework of gray dolostone 

bands end sheet cavities requirsd fluid support under elevated fluid 

prellNmh. 

mt-On St* U - wring uplift of ths Urn9 Range, mst regional 

faults direlaced coarse &lostm/sphalerite -1exes. mldtization 

within 10 B 300 m of these faults altered Catoshe end Table mint 

limstones to squigranular fina to medium crystalline dolostonse rith 

ubiquitous intmrcrystaliine pores. Bcth saline formational fluids and 

meteoric water. migrated along the faults and left a varied 6'"o 

isotopic imprint on the dahstones. Henatit. deposits and svlphate 

crystals attest to the oxidizing effects of some of these fluids.

14.1 Intmdnction 

The development of epigenetic -1exes can he separated into 

seven stages (listed at the end of Chapter 9): (1) initial tsotanie 

developnent of a fractured frmeuork; (2) crystalliaation of perveslve 

pre-ore dolostones; (3) major fracturing and partial dissolution of 

marse dolostmc beds; (4) deposition of sulphidea; (5) crystallization 

of post-ore dolostones and calcite; (6) regional faulting and uplift; 

and (7) crystallization of late fault-rslated dolostones. Certain 

pmc~sses were ~ontinuously or intermittently active throughout the 

history of the maplexer. Significed episodes ot fracturing scparate 

early and late sulphide depusltion and predate the precipitation of bath 

saddle ~olmites nand 8. Dissolution appears to have mntinued 

throughout sulphide deposition end sulphidea were partially dissolved 

prior to the t n phases of saddle dalmite precipitation. 

14.2 -1- of the Initial StrucNral R-k 

stratabound vein systems occurred in the upper Catoohe Formation 

where thin, brittle dolostone beds fractured between coarse dolortones 

in response to deformation along steep favlts and around vrrsi~ bndies 

of mck-matrix hreooia. Fracture systems developed in milinear zones 

that spanned 3 to no m thick stratigraphic intervals. Bsrly fractures 

deeply penetratsd stratigraphy along faults. Deformation then pmpagat- 

ed fractures outward fm faults into pmgresrively higher htratigraphis 

levels and thinner packages of beds. Solution collapse and hydraulic

,159 

fracturing during fluid migration thmugh the fracture systems Increased 

tho anaunt of tractuting and brecciation. 

14.3 ElyBtalliMtim of PIsOrr Dolostonss 

nodies of pze-ore medim to marse matrlx dolostone (IV) over- 

printed oarbnatss in vein systems. pine to medium gray dolostones 

selectively replaced lime wackestones and overprinted mdium crystalline 

early burial dolostones (11,111). Coarse matrix dolostone preferentlrl- 

ly replaced peloidal grainstoner. The dolomitizing hydrothem1 fluids 

migrated along faults and fradwss and formed zebra bends along double 

diffueion fmnts where the fluids enantered fornationel watsrs in 

coarse dolostone beds. 

14.4 mj0Z PraOhlring d D I~801~th 

Continued deformation fractured pre-ore dolostones (IV) and 

dilated earlier frasturan. This increased pemebility and focused 

fluid flow. Fluids entering the upper Catahe Formation extsnsivsly 

dissolved the oarbonatea, creating m y regspores and neswrer In the 

wrae dolostonss, including eheet pores in zebra rocks. mrmsive 

fluids mld have hen generated in a number of vaya: (1) by production 

of a,, hydmcarbon gar and carbmylic acids during them1 maturation 

of kerogen betveen 80- and 20O0C lschnidt end n00onald. 1979; Kharaka et 

.I., n83. 1985; Ranks and Foraster, 1984). (2) by sinpie recharge of 

ME- enriohed meteoric watsrs into basin sedimnte (Eack and Hsnrhaw, 

1971; sitshon et el., 1971). (3) by the release of CO, during mta- 

mrphis. of carbonate rocks at 500° to 60OnC, (4) by the release of W,

during reactions between carbonates and clay mineral3 at l8OD to 225'C 

Zll3U 

(Hutcheon et al.. 1980). (5) by acids of H.CO,, H,S and H,SiO. possibly 

carried within mstal-bearing solutions (sverjensky. 1981, 19861, (6) by 

undersaturation of waters at the deposition site during mixing of tw 

fluids (Marre and Sullivan, 1977). or (7) by production of acids (H,S. 

H.m, and HC1) during svlphide precipitation or sulphate reduction at 

the site of dewnition (Inderson, 1983). Ths presance of hydmcarbons 

in the region suggests that organics could have been the source of 

aoids. The lnst probable sources of corrosive cqonents, howevsr, ware 

the accu~llation of a). and acids in fluids at depth, production of 

acids during svlphide deposition and mixing of t w fluids et the ore 

site. Petrographic and field observations suggest that all three 

processes oould have operated. Bignificmt dismlution happsnad in ore 

zones prior to svlphide deposition, but corrosion also oecurred 

synchronously with precipitation. Widespread dissolution wall beyond 

the areas of sulphide deposition pmbebly resulted fmm undersaturation 

with respect to calcite/&lmite during fluid mlxing. 

14.5 DepitiDn of Solphldu 

sphelerites precipitated in t w min stages, the resulting cement 

stratigraphy of which can be traced laterally throughntt the nine area. 

Early sphslerite crystals were fine-grained to fibrous in habit. They 

precipiteted rapidly in disseminated pores and frectvres end l~ally 

massively replaced gray dolostones. Contmpraneous fluids aided by 

acid pmduots of sulphide precipitation dissolved rurmunding dolostones 

and enlawed pres, which were subsequently filled by slwly precipitst-

ing coarse crystalline sphalerite at the end of the First rtaqe. A 

period of fracturing Wcqanied faulting between early and Late stsges 

of mineralization. late mineralizing fluid$ shifted to these highly 

pemeable new fracture zones where late sphelcrites prccipilatcd'es 

mssive deposits of coarse pcre-filling crystals. Regional fracturing 

461 

and dis~lutinn of carbonates preceded extensive crys'~1llzut~on of the 

latest yellov-block sphaierlte. These important relationships d ew- 

strate that mny veins, solution prsr and breccias Eomsd in the midst 

of ore depoait on. 

In a auijerted ridel for o n dsposition, it is hypothesized that 

buoyant, warn, metal-bearing fluids mre thmugh fractures, possibly 

directly frra baswnt depths. Dissolved gases of CO, nnd H,S my havr 

enhanced the buoyancy. Upon entering the fractured aquifer of the vpper 

Catoche Formtion, the fluids mse to the top end €loved laterally along 

porous beds and linear fractures beneath iwervious beds of finely 

crystalline dolostone. Hetai-bearing fluids probably sat ebove cmiar 

formational fluids within p rm* coarse dolostma beda. Abrupt ore 

cantacts along inpervims bla& dolortone bands marhd baundsries of 

minor mir'nq. Contempranems dissolution and fracturing incrossed 

porosity and pmsability which redirected fluid Elm to Itreas beneath 

and outside of older deposits and created paras thmuqhout the deposits 

for late coarse svlphids cementa. The nature of the ore fluids are 

considered in section 14.9. 

Y.6 crystalliza~on of --ore mlostones aria calcite 

~hmughmt northwest Nsvfovndiand pseudobreccia end associated

coarse do1os:mes (V.VI) crystallizad after the sulphides, filled 

162 

ub~g~ito~s pores and'overpr~nted mrt pre-om dolostones (LV). Cencnts- 

tion and .elesti"e replacement by Saddle Do1mite A cmpleted the 

development of zebra dolostoner. 

In the chain of post-ore events reg~onsl dcfomtion extensively 

fractured aphaleriter end daloatanes, then allochtho~us brines migrated 

thmugh the fracture system and pervaded regionally porous dolostones. 

The fluids were underraturatad with rorpact to sphalente nnd partially 

dissolved the aulphides. Wst-ore dolostones (V) cryataliized following 

the releaas of m, during Eracturing and while fluid tmpraturss still 

exceeded 10OoC. Saddle Oolwits B and calcite with distlnstlve isotopic 

slgntltursr precipitated after later fracturing during progressive 

~ ~ and decreasing 1 1 mck-water ~ interaction as fluid flow =loved in 

cemented and dhinirhad pores. Late pyrobitmn covered wg surfacer 

during a late hydmthsml event when hydrasrbons cracked. 

A zonation of dolostone fasles developad across the dolostonel 

sphalerlte snplexes. In the fractured centres of d/s -1exes saddle 

Dolomites A and e cemented abundant veins, solution mapores and spar 

brecclas, and outside of defomd zones Saddle Dolomite A cemented 

mesopores and replaced marse matrix dolostonas (Iv) to fom bedded 

pseudobrecciaa. Coarse spar- dolostones (v) replaced linestones where 

dolomlti8ation extended beyond the earlier limits of pre-ore dolortone 

(IY). 

Elevated fluid pressures wet9 pmbsbly instmntal in the 

precipitation and textural developnent of latp dolostones. Oolmlte 

preoipltation occurred after extensive tectonls end pmbabls hydraulic

Fracturing as the sudden decrease in are Iluid presoure and pm, 

dropped dolomite solubility (Sippal and Glwer. 1964; ~,€e ~t al., 

19791. lou angle ore stage veins inply that any hydraulis trscturing 

propagated under a tectonic regbe virh a near-horizontal direction of 

regional ~rasrim. 

467 

Thmghollt the crystellizatlon 01 sphelerite and coarse dolostonos 

the canbination of elevated pore fluid pressure near lithostatis 

pressure and tectonic oxtenston maintained extensive porosity thst 

locally totalled up to 40% of the mck volme in the for. of networks of 

meawraa, nnirtiple sheet cavities and open worL bncsias. 

14.7 Silum-Devmdm Faulting a d liplift 

Regional faults asnaiated vith the Long Range uplift vartically 

displaced earlier coarse dolostone/sphalerite -1exes. Associatad 

folds tilted ore-stage geopetal sediment8 in Ponner cavities. Suiphatas 

and hematites precipitated along faults from late stage mygenatad 

waters. Hmtite also precipitet 1 extensively below present near- 

surfaoe sulphide bodies which possibly lay hedietely beneath e 

regional unmnfonaity of Late Paleozoic or Early Hssaoic ags (Hyde, 

1983; mad, 1987). Buhadral pyrjte crystals with a similar fault- 

related distribution precipitat~d during slightly redusing conditions at 

mderate pH. 

l4.8 ay.rallizetiW of late vault-related mloat-s 

Fine to medim crystalline dolostones replaced St. George and 

Table Head limestones along the late faults. PracLures and solution

pores were cemented with minor saddle dolomite and bnght luminescent 

calcites which may cdrrelate with Late Paleozoic to early Mesozoic 

,164 

cs1cit.s in Cevboniferws strata of the Port-au-Port Peninsula (Saundsrs 

and strong, 19861. 

11.9 Nature oE the hesinal Plvids and Their Trmprt 

The fhid inclusions preserve remnants of the original hydro- 

thermal IBSDC to 185'C) brines f m uhioh aulphides and epigenetic 

dolomites precipitated. Theae highly saline fluids with CaC1, and 20 to 

greater then 24 equivalent weight 8 NaCl canpen with deep basinal 

brines found hela 2km in present day basins (e.9. Hhitb, 1964; Hanor, 

1979; S~erjensh., 1984). The positive 6"S values of sulphides and 

sulphatsr confirm that the brines were largely derived frm sedimentary 

sulphidez or rulphates or connate sea water trapped within Lwer 

Paleozoic mob of the sedimentary basin. Many MVT depodts, however, 

have never bean burid to the depths st whieh Ehids of such salinity 

and te-ature reside, thus nost ore deposition mdels prem that 

fluids migrated to nast deposits fm. the deeper parts d basins IOhle, 

1980). 

l e basinal brine hypothelis, the popular theory f%- flllid trans- 

port ((eg. Jackon end Bealss, 1967; White, 1961; Ohle, 1980). suggests 

that brines flushed art of the doep basln along stratigraphic 

aquifers to shallou nraqinal platfoma. Recent studies of stratigraphic 

dolostones donunent dolmitization fro. fluids which migrated along 

regional aquifers (Gregg, 1985; Rowan, 1986; Voss and Hsgni, 1986; 

~orm et al., 1986: Premn and Hedary, 1981). Neshanislas of fluid

igration and mture of the fluids have not, however, bean clearly 

established. ' 

Several models exist for fluid transpart in ssdimsntary basins. 

mpaction dewatering of brsinal shales are envisaged by Jackson and 

=ales (1967) as a mans of deriving metola and large ~1-s of sallne 

water. In young basins, such as the Gulf of uexim, compaction driven 

end geopressuled fluids rdgrate both up shatigraphic dip end up dong 

faults (s.9. Gallway, 1980. Hydrological models (I!+& and Hsnshaw, 

I65 

1970; Garvin and Freeze, 1984; Garvin, 1985; Bathke, 1986) mphrsize the 

importance of topographic or gravitr-driven flew to Plush the basin at 

rates of flow great enough to maintain elevated fluid tenpsraturea. 

This model particularly eppliss to mature basins rimed by topographic 

highs. Orogenic events involving lmjor thrusting such as the Llleghcn- 

ian orogeny are identified as periods of major gravity driven flow 1e.g. 

Leach and Rwan, 1986). m e wrkers suggest that tectonlc "pwping" of 

pulses of fluids ran, oeoessllry to maintain anmlouri temperatures 

(Sibson e t al., 1975; Ulthles and %%tithe 1983). Deep hydrothermal 

fluids driven by thermal mnvectios without the aid of gravity-driven 

f b rise thmugh owlet overlying waters along permeable pathaya such 

as growth faults or pomus s9iferp (HaMr. 1919; b d and Wtt, 1982; 

s b , 1984; Kreitler, 1987). In any d these models maintenance of 

hydrotherml temperatures at high rates of fluid flow rowires mnduits, 

svoh as faults and cavity-riddled fomations, with permeabilities around 

one darsy [Kreitler, 1987). 

by hydrcqeologieal models for the Danisl's Harbour depohit mat 

sooount for the -1.x twtonostratigraphy of the Hmhr Zone and that

416 

Iha deposit pre-dates basement uplift. AS 8 result the Daniel's Harbaur 

setting differs significantly f m the Pine mint nadela of ~ackson and 

Heales (1961) end Gsrven (1985). The mineralization part-datmd Middle 

Ordovician defomtion and tectonic displacerent of hasinai shales Lo a 

position abwe the platformal sequence. The resulting Taconic thmsts 

probably constrained later lateral transpart of fluids. The sulphldv 

deposition was probably coeval with ervly radian crustal heating, 

deformation and fraoturing. The CrvDtal heating probably drove fluid 

convection and caused metal and sulphur release thmugh mineral trans- 

formations and hydmtheml leaching. Ths fractures prwlded fluid 

~onhlits. The ocourrence of minsrelizetian on major lineaments ern- 

phasizes the importance of Eraoture-controlled fluid flow. Ths impor- 

tance of gravity-driven flow is unknown. Stratabound coarse dolostones 

and rphslerite bodies m ly lotsrsl fluid flw. A lowland terrestrial 

to shallov marine geography prior to uplift of the Mng Range, h0w-r. 

probably lacked a mntainous upland recharge area capable of generating 

significant hydraulic head. 

RKI different mdelr for ore deposition propose that either one or 

two Fluids carry metals and sulphur (Sverjensky, 1986). A single 

hydrothermal metal-baaring fluid with reduced sulphur (H,S) would retain 

soluble metals only at an acid pH less than 4 (Anderson, 1973). If ouch 

a fluid travelled any distsnoe thmugh carbonates it wvld be hlffered 

to alkaline pH and precipitate sulphides, unless original concentrations 

of ca and partial pressures of total dissolved a, were high (Anderson, 

1983). Pl. a result of this solubility problm, Anderron (1915) and 

other8 hypothesize that -tall are transportsd In an oxidized solution

free of H,S and precipitate sulphide when they nuet reduced sulphur in 

46'1 

another fluid at the ore site. Other workers suggest that SO. or partly 

axidised aulphur species are carried with the netnls and precipitate 

suiphides during organic or inorganic reduction of aulphur (Barton, 

1961; Anderson. 1983; Spirain, 1983). H,S-bearing ijthologics, such as 

saw rock-matrix braccies, could provide a local swrse of sulphur 

andlor a reducing envimmnt for sulphide precipitation. 

Certain feeturca of Daniel's Harhr and other MIT deposlts favor 

precipitation fron a single fluid. Firstly, the narm ore lenses with 

their abrupt contacts surrounded by barren doloatones suggest Lhat ore 

fluids only travelled locally in the upper Catoehs mmtion end 

experienced minor nixing with fomtional fluids. Secondly, the 

regional mltilayered sphalerite stratigraphy has severel implications. 

Diaermilibrivm between fluids, sulphides and csrbonates is indicated by 

pre-ore solution pores in dolostones, by sulphide mplacemsnt of 

dolostone and by ~olution-etched surfaces on ssuscessive crystal layers. 

This repeated dissolutionjpresipitation differs fmm the asmd 

irreversibility OF Bulphide precipitation during mixing of fluids 

(anderson, 1975, 1983). me extensive nature of the sphalerite stratig- 

raphy slsa requires unifom conditions for precipitation over a bmad 

area which is difficult to achieve along fluid mixing fronts (ncclirnans 

et al., 1980). The variation betwen early stage rapid presipitatiou 

and late =tag= sior grwth of coarse crystals elm contrasts with rapid 

"dwing" expeoted upon mining of fluids. Lastly, the apwrent decrease 

or 6"s values away fm fracture zones or centres of fluid fla 

suggests that avlphur was carried in the metal-bearing fluid.

m to moderate PI! brines carrying reduced sulphur sp~ies 

(sverjonsky. 1981. 19861 is an attractive d e i for metai transport in 

this setting for several rweons. fn bssement and baslnal wurcr areas 

such fluids would effectively lsech metals. wring rans sport dissolved 

lh8 

HIS gases wmld enhance buoyancy end abundant CaCi, and Co, would rotard 

carbonate buffering. At the deposit site fluid temperature and w.. 

partial praaaure wwld decrease with Fluid expansion in tho interval of 

stratabound fractures. Simultaneous dissolution of carbonaten by acidic 

solutions would canbine with the changes to buffer the flvidr and result 

in extensive sulphide precipitation. Successive generations of acidic 

fluid would repeat this pmcesa leaving e stratigraphy of dissolution 

surfaces between crystal layers. 

In a auggasted nodel epigenetis fluid migration acuresd in the 

early stages of the Rcadian Orqcny when orvrtal thickening end snatexis 

heated the sedimentary pile and generated them1 convestion (Fig. 

14.1). Pit the s w tine steep frestuysr, including reactivated O r 

dmician strvctures, created fluid conduits (Fig. 14.2). Deep haninel 

fluids, fm. more than 2 h depth, circulated thmugh the basement and 

up along faults. Iateral Fluid novenant may have occurred as well along 

faults by gravity-drivsn flow. The hydmthed fluids were buoyant 

relative to other formtionel waters whish they displaced at the top of 

aquifers in the vpper Ptahe Porntion. 

At the deposit site fluids entered the upper Catoshe Formation in 

five mein ztages following repoated fracturing events. The first 

hydrothermal fluids caused pervasive dolmitization along fractures. 

subsequent fractures tapped metal-bearicq brines in the deep portions of

igure 14.1 schematic rross-section of the northern Appalachians 

in the Late Silurian: the Prmeuork for Fluid Flar 

The regional setting of mineralization is reconstructed for the 

late Silurian - early Devonian prior to uplift of the Iang Range. 

Baslnal uaters oould have been noherged in terrestrial regions to the 

southeash and hydraulic head caused gravity-driven fluid flow. Struc- 

tvrel buridarles and mstmr~hosed tereanes my, hanver, have hindered 

fluid flw. Them1 convection above an alevated gwtheml gradient 

war an alternative cause of fluid mvment. This prwess could have 

ganerllted vertical novmnt of heated, therefore less dense, fluids up 

stoep basement-releted fracture system.

WESTERN CENTRAL 

SHIELD ANTICOSTI FORELAND BASIN NEWFOUNDLAND NEWFOUNDLAND 

I Nw

Figure 11.2 Fault dnd Stratigraphic-Cantrolled Routes 

of Fluid Nigration 

a nmnstrustion of the plotform stratigraphy st the end of the 

Silurian indiestes the distribution of soersa dolostones (cross-hatched) 

as stratigraphic units and dismrdant bdies (cross-hatched) enveloping 

faults. Suggested mutes of fluid migration (ermwr) are vertically up 

along rauitr and laterelly outwerds along stratigraphic horizons.

'ROUTES OF FLUID M!GRAT\ON 

IN THE NORTHWEST NEWFOUNDLAND PLATFORM 

MAINLAND SANDS TON^ 

TABLE HEAD GROUP

the basin during R them1 peak. ~nitial ore fluids roam up deep 

.I71 

fracture zones, entered the vppe. Catoche Fomtion where they dissolved 

carbonates to Porn, abundant megapores and sheet cavities prior to the 

rapid crystallization of early sulphides. Ths pre-ore dissolution and 

extensive whalerite stratigraphy probably resulted frm acidic are 

fluids of largely unknwn cqoaition which probably carried b th metals 

and reduced sulphur. Late stage ore flvids flowed only along one 

fracture zone, the L and T Zone trend. Pragrcssivs feultinq and 

fracturing throughmt northwest Newfoundland opened the region to 

extensive fluid migration and post-ors dolmitirstion. During this 

fourth stags late yellow-black aphalerite widely precipitated end Saddle 

Dolomite A closed mch of the ubiquitous porosity. Mter a late 

fracturing evmt in the fifth and final stage mgacryntals of Saddle 

Dalcmite B and calcite occluded pores ee fluids pmgressively cmied and 

increased in salinity. later epidic invasions of hydmtheml Fluids 

probably resulted in the precipitation in vugs of marcarite, galena, 

late red sphalerits end pyrabitumen. mrther dolmitieation (VII) 

oonvred elow faults during ard after regioml uplift (Stages 6 end 7 

at the beginning of the chapter).

a(* PT 

sLnav.Ry AND CONffiUSICaS

mring the deposition of the upper St. ~eorge Group in the Early 

Ordovician. the carbonate platform progressively shallowed upwards from 

(1) an open marine, subtidal, nwddy shelf (Cetoche Formation1 to (2) 

shallw rubtidal flats rovered by peloidsl grainstonas and md beds 

(upper Catoshc Formation) to (3) arid peritidal flats (aguathurm 

Formation) (Fig. 15.lbc). Many laterally extensive beds ac-leted on 

a nearly 1-1 platform as noderate qlitude cycles of marine flaading 

and regression inhibited normal processes of tidal flat progradation. 

Tmrd the end of Early 0rdar:si.n the the platform fragmented 

along northeast-trending faults and ua extensively axposed during 

regional uplift and/or eustetic rqression. Initially sedimntation 

continued as the middle mnbsr of the Aguathune Formation filled grabens 

and subsidence dolines along faults and itbave stratabound olimict 

brecalas. Faulting continued and differential uplift occurred as the 

entire platfom becam axposed. At this the erosional beveling of 

weed St. George carbonates created the St. Gsorge Unconfonaity. At 

the same tine subsadace waters generated callapse dolines along faults 

characterized by solution cavities, discordant polmist breccia. and 

surface sinkboiss. 

subsewent mine onlap mer the St. Owrge Unconfonaity in Early 

Niddls Ordwiaian tine locally raaulted in deposition of cerhnate muds 

and reworked residual ehert hmds which cqrise tha UPPB~ member of the

igurn 15.1 Sedimentary evolutiarr of the Pletfm at the end of the 

Corly Ordovician and during the early niddle Ordovician at the mine 

a. niddle Cetoshe Formstion - Scattered thmdmlits mndr charas- 

terized an open marine mddy shelf with intreclastic, skeletal stom 

beds end mdstoner. 

b. Uppar Eatoche Formation - Peloidal grainstones daoinated very shallow 

wdter aubtidal Flats. 

c. Lnnr Armathuna Porntion - Supratidal flats of dolelminiter 

alternated and lnterfingered with burrowed mdrtones d intertidal to 

suhtidal flats. subaerial regions along fault bloas to the north were 

prominant by the tine of the middle nabsr. 

a! Upper Aguathuna Porntion - A veneer of paritidel dolamdstones 

mvered en irregular topgraphy of sin!&oles an8 shallow flats. 

e. lower Table Point Formation - M irregular topography of peritidal 

flats and subtidel areas were covered resp,psctively by fenestral mu+ 

stones end nodular bioclastis wackestones.

a. MIDDLE ClTOCWl FORYATloH 

b. UPPER CATOCHE FORMATION 

c LOWER AGUATHUNA FORMATlMl 

d. UPPER AGUATHUNA FORMATION 

r LOWER TABLE POlNT FORMATION 

SEDIMENTARY EVOLUTION

aguathuna mnnatia. ~nitially argillaceous llm muds accumiiited in 

sinkholes and valleys on the Unconfomity surface; but lime muds 

blanketed much of the the pliltfom (Fig. 15.ld). 

.I78 

mw relieE towraphy perrisked as Table Point perltldal sediments 

(Spring Inlet Henber) accwlated on bmsd islands (Pig. 1S.ie). 

Subsurface karst mccurred as deep-seated netsorie aquifers generated 

lmal dlhney pipe breccias. 

Increased subsidence eventually probced shalla subtidal condi- 

tions acmss the plattom. Sedimentation, hmever, kepl pace with 

subsidence until the platfam abruptly founder4 end a siiiciclastic 

foreland basin was generated prior tn ths emplacement of Taconic 

allochthona (~tenzel and aiuea, 1901, 19BB). 

15.2 ~lmitiestion an4 ~wietion huiq Early Burial 

Mlmitization of the upper St.Georrje Group carbondes began at or 

jost below the sedilaent surface. Early '"0-enriched, finely crystalline 

dolmite (I) selectively replaced peritidel mudstona beds. Clastl of 

these dolostones wore incorporated In pebble beds on erosional surfacer. 

in ather intrefomti~l conglmrates and in suDsurfecc karst brec- 

cias. 

Brccsiation causod by subsurface karst spanned the the fmm 

deposition of the middle member of the Aguathuna Pomstian thmgh 

deposition of the lanr Table mint peritidal limestone. Gmund waters 

attacked the upper Catoche Famation as they migrated along northeast- 

trending faults. Three stager; of subsurface karst are rawnizrd: (1)

,119 

extensive rtratabovnd dissolution of Limotones in t,hs Catocha Pomtiun 

leading to subsidence, (2) deep, local dissoiulioo of limstones olong 

contnnporsnems faults folloued by callapsa and cave filling vith 

polylnict hressia, (3) late fornation of chimney caves beneath the ~ohie 

Point platform. mntemporanews Eluida circulated along faults and 

doimitired (1, 11) the breccia matrill. 

Middle Ordovician redbents (7001 n thick) and aliochthons (5001 m 

thick) burisd the upper St. George Group to depths between 100 end 1500+ 

m. Dvring the burial Catache iimsrtones vere progressively 

recrystallized and &lomitired. The relationship between burial, age 

and dolomitisation is presented graphicelly in Figure 15.2. Unapaaila 

dolomite crystals (11) vith turbid cores and clear rim nucleated near 

the surface and cwleted their g mth along stylolitsa. After initi- 

ation of stylolites and a fracturing event, alloshthonous brines 

migrated along fractures, through dolostones and locally dissolved 

lhestonea to form secondary pores. Clear, zoned Dolomite 111 cemented 

these pores and sealed early dolostone beds. 

15.3 Epigcwtic Cdmithation and 8ulpMe Winerali!atatio. 

The St. George Group was buried to a mauiwm of 2 to 3 h (bared 

an the them1 lneturation of conodonts to CaI of 2 to 2.5, Novlan and 

Barnes, 1387). This occurred between ths Late Ordovician and Late 

silurien (rig. 15.2). In the Silum-Devonian the platfam war deformed 

along reactivated northeast-trending fsulta in response to regionel 

-cession at the winning ot the wadian Orogeny. Llnesr, strata

~igure 15.2 Relationship of Dolonitization Kventr and Sulphide 

Ninerslization to Burial of the Uppsr St. Oeoge Group 

st Daniel's Harbour. 

Timing of dotmitization events is relate3 to depth of burial. 

mlanite I Pomd near surface and mostly pre-dates karstification. The 

pmlc@ gwth of Dlmites I1 and 111 ossurred after karstificatinn 

and durlng burial beneath Middle Ordovioian sadhnts and the Taconic 

Allochthen. naxianun depth of burial is unhown. Ths upper St. George 

Gmup was buried beneath a minm of 1000 m of lmm Wer rocks. I€ 

comdont alteration indices of 2 to 2.5 directly reflect burial, 

however, the overburden was greater than 2500 a. Kpigenetlc dolait- 

ization (IV, V and VI), aulphide, nulphete and hydrosarhon deposition 

aocurred in assacistion with regional fracturing during the initial 

Stage# of lioadien uplift. late fault-nelated dolmitization (VIIJ 

occurred along late steep faults associated with basmenit uplift daring 

'the clim of the Acadian Omgeny. Subsequent dissolution of inter~rys- 

talllne lhstone created secondary pomlty *hi& putidly filled with 

calcite, saddle dolonite end hydmartms.

and fracture systems fomd as another pmduct of the deformtion 

event and served as conduits far the migration of hydrothem1 brines 

which generated coarse dolostonelsphalerite bodies. The first fluids 

locally dolmitised upper Catache limestones and overprinted earlier 

dolostones (11.111) along fractures. Subsequent higher tenlpereture ore 

fluids partially dissolved carbonates prior to the precipitation of Lhc 

first sulphides. Multiple layers of sphalerite precipitated throughout 

the mine araa as fracturing and carbonate dissolution continued and 

fluid tmeraturer decreased. Vertical fault displacwnt and brwd 

fracturing along the Land T Zone* localized the flow of late ore 

fluids. 

Extensive fracturing and dilation of earlier fractures prscaded 

1 M'1 

widespread post-ore doldtiaation (V) which overprinted earlier mdium 

to coarse orystalline dolostones (11. 111, IV) and replaced limestones. 

saddle Dolomite a filled ubiquitous veins and solution pores end 

partially replaced doloatones. mte saddle Dolomite 8, oalsite and 

sulphates precipitated in pares as late Iluids progressively cooled to 

50DC) and increased in salinity. Late sulphider and ,-bitman 

during intennittent late invasions of hydmtheml fluid. 

15.4 Dolmititiration Baletad to Regional Uplift 

During Iata stages of the Acadian Orogeny regional uplift frag- 

mented and displased the platform stratigraphy, including DIS mpleres. 

Di~cordent dolostone. ("11) replacad limstonea nurmvnding mmt of 

these faults. Dolostones above thrust faults probably developed during

syntectonic fluid migration. Other dolostones with variable isotopic 

signatures crystallized during post-tectonic, meteoric fluid mvenent. 

Thess fluids also generated a ubiquitous vuggy porosity which leta 

483 

saddle dolmites and oalcites partially oenented in the Ute Palwzaic.

PTimry lithology and fracture lineaments oonstitute the two mjor 

controls M pmoesses thzmghout the buriel history of tho upper st. 

George Group. Mudstones were aelwtivsly converted to doloatone (I) 

beds near the surface. In early burial these beds besm aquifers and 

later, after being sealed by Dolonrite 111, acted as stratigrsphlc 

equicludes. During deep burial they behaved brittlely vhmn deforned, 

thus gensrating the stratabound, freoture aquifers which carried the ore 

Fluids. Peloidal grainstones of the upper catoche Formation, in 

sontkast. remained limestones during early dolomitiration (I). As e 

result they were locally subjected to meteoric dissolution and only 

leter altered to coarse, permeable dolostone during deep burial. 

syosedhntary faulting along mrrtheaat and northwest-trsnding 

linemnts conmllsd deposition of the middle mehr of the Aguethuna 

mmtion and later sediments ma alsoprovlded conduits for local 

~ubsurface karst. Reactivation of these same linements during early 

burial dalonitization (11, 111) and late &pigenetic dolwitirstion [IV, 

V) renewd fracture-contmiled fluid mvement. During regional uplift 

high angle raveme faults formed along northeast trends and mdmt~rlled 

late fault-relate4 dolonitiaetion (VII). Further vertical and strike- 

slip displacmmt occurred along many of these structures in the 

Carboniferous.

16.2 Nat- of the St. m e Unconfomity 

The stratigraphy of the upper St. neoqe nmp relleots the 

progressive shallowing and svhnvfeoe karstification of the piattam in 

five stages during the late Canadian and early Whiteroctian. During 

extensive sedimntation of the lmr Aguathuna Fomtion (Stage 1). 

peritidal sedimnts rhythmically "deepened" upwards into regional 

intertidel beds with erosional caps, interpreted as a response to 

mderete amplitude sea level o~sillationa prior to marine regression. 

Extensive sedimentation ended as the platfom fmpntcd along north- 

east-oriented fractures. The middle W ar of the Aguethuna Formation 

acwlated over subsiding fault blocks and subsidence dolines reletsd 

to subsurface ground *ator dissolution of Idstone in the upper Catoehe 

Formation (stage 2). continued faulting displaced these strata end 

subsurface collapse hrecsiaa during regional deformation. marine 

regression and wsure of the entire platform (Stage 3). Wring this 

hiatus laeteo~ic waters excavated the Catoche linertones along these 

faults. The agathuna Formation then collapsed over thess mvss as they 

filled with polymlot mck-matrix breccia. causing collapas &lines to 

fom on the surface. Erosion left a lnrrelief topography (chs unson- 

Comity surface) as it bevelled s gently folded and faultad stratigraphy 

and locally mved up to 80 m of eection. During marine mlap a veneer 

of pecitidal dolortones f ilm sinkholas and awered this topography. 

Subsurface karst occurred again beneath psritidal limestones near the 

base of the Table mint Fomtion as beds collapsed during the develop- 

ment of chimney breoeias.

Host dolostone beds in the mine aces rscod two to six episodes oC 

dolmitieation (Fig. 0.1) which occurred in four main envimnmnts: 

ryngsnstic (I), diagenetic (11, 111). apigenetic (IV, V, VI) and post- 

uplift (VII). Symlenetis dolomitiretion (I) replaced subtidal to 

supratidal mudstones and breccia lnatrix in ths subsurface. These 

mi~r~;rystalline, "0-enriched dolomites fomd at or near the surface 

as implied by doloatone (I) frawnts in mnglmrataa and karst 

breccies. Evaporative processes on the aridlresristad pletforn probably 

generated this dolmitiration. The extensive, repiacive dolostones, 

locally penetrating stratigraphy along faults, suggest, hwevsr, that 

dolomitiration extended beyond the zone of evaporative reflux-aabkha 

P~esBBh. 

Tumid to clear crystals (II end 111) are defined as diagenetic 

and interpreted to have startad gmth near surface and caapletsd rt 

burial depths of more than 300 m. Early turbid, replscive b1ue-a 

orystals (11) capture insoluble residues and calcite inclusions and are 

partially replaced and werg-n by clear, pink-CL dolomites. These 

crystals oar in limestones as individual crystals and patches replac- 

ing burmrs and stylmttles. They elso form pervasive doloatones in 

uac!estone beds, replacing mskwtrlr breccias and surrounding vertical 

fraohrren. Their nuclsation and early gmuth happened near the surface 

in eymilibrim with the calcites that vsre incmletely replaced. The 

arystals bsme nretastahle with incraasing burial and uere overprinted 

by pink-CL dolmite in response to changing porn water chemistry.

clear, zoned Dolonita III with bright ysllor to red CL occurs as 

~SOPIIC~OUS cements & solution pores and as syntaviai overgrowths on 

Wlmite I1 Erystels. These dolomites ere pertisularly caamn in anriy 

dolostone beds and mck-matrix breccias, both of which #ere permeable 

units at the time. Their oosurrence along dilotent, vertical planes of 

stylolite sutures implies their wevai origin with pressure solution. 

The precipitation of Dolmite 111 i s interpreted to have amurred after 

487 

deep, probably allochthanour, fluids migrated vertically along Fractures 

and laterally along dolostones, caused partial solution a£ calcites and 

dolodtss and became ~turatsd with respect to dolmite. Warm Fluid 

t-ratures, hyperselinity, alkalinity and reducing condition^ probably 

caused the precipitation of the luminescent dolmites. 

@pigenetic dolmitiaation (Iv. v, VI) occurred during d ~ burial p 

(1000 - 3000 m) amund tectonic Fractures, which acted as conduits for 

ellochthonous hydmthemal fluids derived F m a deep source. Xenotopic 

pre-ore dolmitization (14) rsplaced limestone beds and recrystallired 

early dolortone mttlea (11, III), Farming mrse wtrh doloatones. 

Post-ore dolostones (V) overprinted the earlier dolostones (IV) as 

Saddle Dolmita A c-nted pares and extensively rsplaoed gray dolos- 

tones. Replaciw saddle dolmite was a cmon c-nent OF post-ore 

epi-netis dolmitizetion IV). Hegacrystals OF Saddle Dolmite B (VI) 

and late calcite occluded pores as fluids became progressively emler 

and mre saline than -stage ones. 

Post-uplift dolostones (VII) replaced lhestonsr mrrounding late 

faults. Field relationships and variable isotope geochemistry suggest 

that dolmiti~etion occurred during and after uplift frm fomt~onal

tines and lneteorio vaterr that migrated along the faults. 

16.4.1 Timing of Sulphfde Cepasition 

several lines of muidence indicate that sulphide deposition oc- 

ourred prior to regional uplift in the early stages of the Siluro- 

Devonian Rcadian Omgeny. (1) Ore staps dolomites (Iv and v) owlprint 

diagenetic dolomites (11. 111) which probably crystallized during burial 

beneath the Taoonic Allochthon. (2) The sulphid=s fill extensive 

subhorlEonta1 fractures that formed from northwest-directed regionel 

omqression during tho early stages of the Acadian Ompsny. By cnperi- 

son, the Toconic Orogeny caused only minor deformation of the autochthon 

(Cauwd e t al., 1988). (3) Tilting of post-ore gsopetel sediments 

indicates that sulphide deposition pre-dated regional folding associated 

with uplift. (4) Stylolites associated with post-ore dolmites also 

indicate that these pracssses ocourred at depth. IS) Regional uplift, 

and armciatea finutr rrhich displace dolostonel avlphide cmplexes, 

probably occurred during the late Silurian and happnsd no later than 

the early Cerboniferovr (Cavcd et el., 1988). 

16.4.2 uatnre ot sdphide m ition 

sulphide deposition occurred in two min stages as buoyant, warn 

ore fluids migrated laterally along strethund fracture system and 

probably displaced denser, fomtianal fluids at the tg of aquifers 

beneath finely crystalline dolostone awicluder. Separate generations

4a9 

01 E~.actures created tw different pathways lor ore fluids and diErsrent 

depositionill sites for early and late spholeritea. wring the two ore 

stages discrete generations of sphalecib precipitated as extensive 

crystal layers thmughout the mi*- ares. Successive ldycra changed 

abruptly in oolour. crystal hahit and sulphur and imn shemstry. 

hring eaob stage the crystal habit of the sphslerite changed frm 

microorystallins, fine or fibmus crystal6 to coarse, prismatic ones. 

Contenporaneous dissoiutiaa affected previous sulphidss and created 

pomsity in adjacent doloat-s. The final whalerites o€ each stage 

precipit~ted in these w e perneable carbonates. 

16.4.3 lnterpnteton of w i a 

R variety of date suggest that ore Eluids were derived from sedi- 

mentary baoin ustera thst travelled Frm depth up along deep fracture 

systems largely hecause d them1 convection and the buoyancy of the 

FLlid. sphalerite aulphvr with positive Pas valuaa originated from 

lnrec Pqleozois see water aulphate that had been stored in pare waters, 

evapadtes and/or sedhntery pyrite. 'me hypersaline and CaC;x-rish 

iwltsion fluids ere typical of brines from the 1-r sedhentsry pile 

(Hanor, 1979). The high h-eniation temperatures of these fluids 

(mde i4OnC, mximm 185-C) suggest a source at greater burial depths 

than the deposit site. The bas-nt source of W also supports thi- 

aiein iswinden et al., 1988). 

me hydralqieal deiving force is unltnmn. Gravity-driven flow 

f m topographic gmund water recharge pmbably was insignificant prior 

to regional uplift. Them1 heating of the omst ec-nying rmionai

deformtion generated regionel metamorphism and anatexis in the Siluro- 

Devonian and probably ceuaad fluid rmvection wlthin ths platform. 

Thcmally controlled mineral transformations, also, probably rcleescd 

sulphur and zinc £ran sediments leg. Spirakis and Heyl, 1988). Deep 

fracturing, also, prwlded permeable pathways (approaching 1 dercy) for 

the vertical m-nt of fluids. Once the hydrothem1 flulds entered 

vertical mnduits their buoyancy carried them upwards. 

490 

Chemistry of the ore Fhlds, in particular pH and sulphur content, 

is unknown. Indirect widencs, howevsr, supparts the theory that inetala 

and sulphur travelled together in an acidic Fluid (Sverjensky 1911, 

1986). Significant pn-ore dissolution of carbonates SIrggests that the 

fluids were acidic. Dissolution of carbonates and rulphide. end 

rulphide replecemsnt of dolmites throughout ore deposition indicates 

general disequilibrium bstween fluid and minerals. Widespread crystal 

layers illply that 20 and reduced sulphur prffipitsted sulphides from a 

~onnan fluid, rather than at s front of Fluid mixing or sulphur rcduc- 

tion Id. XEClhns et al., 1980). suggested Eractiondion of sulphur 

away fmm fluids conduits, also, intimates that the fluids mntained 

aulphur. 

Acidic fluids, however, cannot travel lor9 distances through 

carbonates and remain unbuffered unless they carry abundant mnts of 

CO, an8 CaC1. (Maarson. 1981). Pn alternative -1 pr-es that 

oxidized ntlphur opsciaa travelled in a neutral ore Fluid (Spirakis, 

1983). These sulphur species ere then reduced at the ore rite along 

fracture-related bdiss of early doloatones which mntain H,S and 

organics. Rock-matrix bcecsiae at the nine contain H,S and disseminated

pyrite in .;"altered early dolostone. (11, 1111. Black dolostonea and 

rmk-matrix breccia. within or adjacent to ore zones are altered by 

epigenetic, dolomitization (IV, v) and lack or have lost H,S or or- 

ganics. 

16.5 Rat- and migin of Kpigenetic Oolostone Fabrics 

Paeudobreecia, the ore gangue, is a post-ora dolostone fabric 

which overprints several generations of pre-ore dolortone in the upper 

Catocho Porntion. A typical pseudobreccia Fabric consists of & 

patches of gray dolostone surrounded by bath replacement and pore- 

filliai crystals of white, saddle dolomite. 

491 

Zebra doloatone, a farm of pseudobreeele, has a distlnstive Eebric 

of multiple, rhythis gray dolostono bands separating "bands" of saddle 

dolomite. The zebra fabric is laralized claw faults end fractures 

where it c mnly dips into these structures. Cmss-cutting sheet 

cavities and veins filled with sphalerits and saddle dolmite indicate 

that the origio ot the fabric pre-dates ore deposition. 

PrevdDbreccia fabrics vary aysterraticelly ssmss the linear, 

stratabound fracture system in the uppsr Catoche Pornation. Saddle 

dolmite occurs only in veins and patches of pseudabrecsia in early 

dolortone bodies adjacent to vein system. Wegapres and zebra fabrics 

ere abundant amund the fracture systems. Regular prsudobrsesic and 

coarse *parry dolostone occur outside of fracturat;. 

~hese dolostonea acquired their fabrics over rr minimum of 4 events 

(Fig. 13.3) when fracturing preceded the migration of aliochthonous,

hydrothermal fluids into the upper catochc Pornation. Initial hydm- 

tilerma1 fluids migrated up along early fractures and Iaterelly thmugh 

fractures and limestone beds. They probably encountered Eorrnati~nal 

fluids st frecturalbad intersections and nixed with them along doubls 

diffusion fronts. Dolortone bands lzebrr. fabric) doveicped along 

diffusion layers where they :nll%zted an andance of insoluble mate- 

rial. At the m e tine xenotopis dolostons (IV) replaced early dola- 

stone stylmttles (IT, 111) and rurronnding ibcstone matrix. 

A second generation of fractures tapped emlwsly hydrothem1 

fluids which carried metals. The underaaturated, possibly acidic. 

Mnes entered the uppei Catochs Fornetion where they preferentially 

dissolved matrix dolortone and remnant patches of limestone, but not 

492 

zebra bands. The dissolution of dolostones con'.inued throughout periods 

of sulphide deposition. Slrlphides precipitated around the -gins of 

there secondary pores and looally replacsd dolostoner. Subsequently. 

geopetal carbonates settled on top of sphphalerites at the bottom of 

pores. 

Pollwing ore deposition, late hydrothem1 fluids, satursted with 

carbonate, pervaded the antire region along an extensive network of 

fractures, causing pervasive dolmitization (V). Saddle Dolomite A 

cemented mst pores and axtensively replaced matrix dolostons IIV). 

Xenotopic gray dolostones (V) recrprilUzrrd the mining dolastannr 

(Iv) and gepetal sedhntr. 

saddle oolmite B, calcites and sulphater precipitated when cwisr 

and more hypemaline brines migrated up along late fractures. The 

precipitation of these and all port-ore cartmeter probably occurred

when fracturing caused the partial pressure of m., to derrease and 

inming hydrothermal brines zncreased pore wetar temperatures. 

a.6 Natme and Signific- ot the v arh ~reeciaa 

Tme bre~eias within the upper Catoche Formtian are classified 

into three types: (1) mck-matrix breccia. (2) fault or tectonic 

breccia and (3) spar breccia (Table 1.2). Rock-matrix br~ci.3 all 

formed by subsurface dissolution between the time of deposition of the 

middle mrber of the Aguethuna Porntion and that of the 1-r Table 

Point Pornation. They are c-ssd of early doloatone (I) fragmnts 

within a distinctive gray dolostone matrix of early dolaniter I, I1 and 

111. Three geometric types ot bodies are recognized (Table 7.3). 

Intrastratal bracclas are regionally extensive beda associated with 

493 

cangl-rste-evaporite horizons in the quathuna Pornation. Stratabound 

oligmict breccias represent local and partial solution of upper Catoche 

linertoner below subsidenee dolines. Discardant polmict bressias 

cmsrout the stratigrephy as vertical, tabular bodies along faults or 

chimneys. These latter breccia. ere the products of wholesale collapse 

of the Aguethuna Pornstion into phreatic caves in the Cstoche Formtion. 

Pault breccia. occur only within centinetres of faults. Small, 

eentimetrc to millimetre-sired, fragments are smnted by white, very 

fine crystalline dalmite (or rock flour). Both fragments and matrix 

are cut by several generations of mck flour-filled veinlets related to 

nwrous episodes of deformation along faults. 

spar brecciaa are typical of fracture zones in osrse dalortonal

sphalerite canplexcs. These "open work" breccia% arc c-nted by 

sphalerite and saddle dolomite. Apparent e-nt support and only 

partial collapse of typisal mosaic breccia. suggests that cementation 

OCCUxred under elevated pore fluid pressures and tectonically induced 

extension. "Splinter" breccia$ and lrsgmsntatlon oP blocks intimtc 

that pore Fluid pressure and tectonism combi~ed La cause hydraulic 

Fracturing and shattering. 

494

ARMP?. D.L.. 1975. On the hydrolopl of the ehrards Linestone, aoath- 

central Texas. Jour. of Hydmiogy, v. 24, F. 251-269. 

UNDERSON, G.H., 1973, The hydrothsmal transport and deposition of 

galena and sphalarite near 10UDc. con. ~wlcgy, v. 68, p. 480- 

492. 

ANDERmN, G.M., 1975, Preclpltstion of Mi~sissippi valley-type ores. v. 

70, p. 937-942. 

ANDERSON, G.M., 1983, Same geahemical aspsets of sulhde precipitation 

In carbonate rocks. In: Klsvsrsanyl, G.; Grant, s.K.; Prett, W.P; 

and Koenig, J.N. (4s.) International Conference on nississlppi 

Valley type lead-zlnc deposits. Proceedings volwne: Rolla, Univ. 

MlSSOUIi-RO11LI Press, p. 61-76. 

WDBRSON, G.N.. 1989, Organic maturation and the orlgin of MVT deposits, 

fabstr.1, Geological Society of America Absritcts with Pmgrams, 

p.u4. 

UNDERSON, G.H. and WVIYZN, G.. 1981. Sulfate-sulfide-cerboboat~ associ 

ations in Mississippi valley-type lead-einc deposits. Econ. 

Geology, v. 82, p. 482-488. 

mERSoN, G.M. and IVLCQUeBN, R.W., 1982, Ore Deposit Models - 6. 

nississippi valley-Type Lead-Zinc Deposits. G-cience Canada, v. 

9, p. 108-117. 

RSSERTO, R. and mLK, R.L., 1980, uiigsnetic fabric% of aragonite, 

calcita, and dolmite in an ancient peritidal-apelean envimmnt: 

Triassic selcara Ros80, Lanardia, Italy. Jwr. of Sed. Petrology,

v. 50, p. 371-394. 

AILSTEM, K.L. and SPENCER, R.J., 1985. Diegenesis of Lhc Keg Rivcr 

Fomatlon, northvestern Albsrta: Pluid inclusion evidence. st~ll. 

CM. Petrol. Geolaly, v. 33, p. 167-183. 

IIULSW, K.L. and SPENCER, R.J., 1981, Diegenerie of the Henelr* 

190 

faciss, Yukon and Northwest Territories, Canada (abstr.). In: Soc. 

Emn. Paieont. Mineral. Annual nidysar Meeting ~stracts, p. 5. 

BACHINSKI, D.J., 1969. Band strength and sulfur isotopic froctionatlan 

il coexisting sulfides. Eson. Geology. v. 64, p. 56-65. 

BACK, W. and HRNSWLW, 6.6.. 1970, Conparison a€ chemical hydrngealogy of 

the carbonate peninsulas of Florida and Yucatan pninsulaa. Jour. 

of Hydrology, v. 10, p. 330-368. 

BAKER, P.A. and USTIIER, Yi., 1981, Constraints on the Formation OF 

sedimntary dolomite. Science, v. 213, p. 214-216. 

BANKS, N.G., 1910. Nature and origin a€ early and late chert. in the 

Leedviile Limedone, Colorado. Dull. mol. Soc. America, v. 81, p. 

9033-3048. 

BANNER, J.L. and HUNSON, G.N., 1989. Simltan-s Isotopic and trace 

dent variations during water-mck interaction: quantltativa 

nwdals vith applications to csrbonate diageneais. (abstr.), 

geolqisal Society of America nhstracts vith Pmgrms. p. A221. 

BARNES, H.L., 1979, Solubilities of Ore Hinsrals, In: Barnes, H.L. 

(eds.1 Geochemistry of Hydrothema1 3re Deposits. 2"" Ed., New 

York, Wiley-Interscience, p. 404-IMI. 

E M S , H.L., 1983. Ore-depositing reactions in Miarirsippi valley-type 

deposits. In: Kisvarsanyi, G.; Grant, S.6.: Pratt, n.r. and

wcnig, J.W. lsds.) Proceedings Volllmc. International Conicrsncc 

on Mississippi valley Type Lead-Zinc Depasi1.s. p. ll-85. 

11Vl 

WNES, H.L.; RDW. S.J. and ROSE, h.n.. 1981, Ores lomd 4 diagennt- 

ic and metmanorphic processes. In: Studies in Geophysics: nlnarsl 

R~SOY~E~S: Genetic understanding for practical appl~cotion,:, 

Washington D.C. National Acadany Press, p. 13-81, 

.EARTON, P. 8. Jr., 1967. bsribie role of organic inattor in thc 

precipitation of the Hississippi area, in BROWN, J. S. lad). 

Genesis of stratiform lead-rinc-barite-€l!~orite dopo8ita. Kcon. 

Geology monograph No. 3, p. 311 - 378 

BIVfHURST, R.G.C., 1958, Diagenetie fabrics in swne British Dinantian 

lhertanes Live-1 end Hanchester. ~eol. Jour.. v. 2. p. 11-36. 

BRTHURST, R.G.C., 1959, Diagenesis in lirrissippian calcilutitcs and 

pseudobrescias. Jar. Sed. Petrol.. v. 29, p. 365-376. 

BATWRST, R.G.C.. 1975, Carbonate sediments and their diagenesia. 

Developments in Sedimentology, v. 12, Ansterdan, Ylscvrer, 62Op. 

BIITHURST, R.G.C. 1980, Strmatactis-origin related to subaarine- 

cemented crusts in Palmzois mud oaunds. Geology, v. 8, p. 131- 

134. 

B&THURST, R.G.C., 1982, Oeueria of atronatactls cavities between 

submrine crusts in Peieozoic81. carbanate m d buildups. Jour. 

Geol. Soc. London, v. 139. p. 165-1. 

W S , F.W., 1911, Cmntation by white sparry dolomite. In: Bricker. 

0.. carbonate cements The John's llopkins University Studies in 

Geology No. 19, The John's Hopkin. Press, Baltimre. p. 330-338. 

aws. P.W. and JAcxYUI. S.A., 1966, Precipitation ol Pb-Sn orcr in

Carbonate ressrvoirs as Illustrated by Pine ~ i n L ore field, 

,1927 

Canada. Canadian ~nst. 9l aining and Metell.. l'ransactionr. v. 79, 

p. 8141-8154. 

EWES, F.W. and HARDY, J.L., 1980, Criteria for the rcswnition of 

diverse dolmite types with an emphasis on studies on host rocks 

(0. Mississippi Valley-type ore depasiLs. YJc. Icon. Paleon. 

Mineral. Spec. ~ubl. 28, p. 197-313. 

BEHFZNS, E.Y. and 1dND. L.S., 1912. Subtidsl Holocene dolmite, saffin 

Bay, Taxds. Jaur. Sed. Petrology, v. 42. p. 155-161. 

BEIN, A. and LRND, L.S.. 1983, carbonata sedlmentetion and diagenmis 

as-isted with Mg-Ca-Chlorids bnnes: the Peamian San Andrss 

Porntion in the Texas panhanale. Jour. Sed. Petrology, u. 53, p. 

243-260. 

BENEDICT, G.L. 111. 1917. Lenoir, Holston and Ottoree Formations: 

shallw shell lagmn, d~eper shelf end shelf mrginal anviron- 

ments. In: s.c. Ruppsl and K.R. walksr leds.) The ecostratigraphy 

of the Middle O&visian of the southern Appalachians, USL: tieh 

excursion, University of Tennessee, Dept. of Geological Sciences. 

Studies in Geology no. 71-1, p. 52-58. 

BETHKE, C.M.. 1986a. Hydrologic constraints on the genesis of the Upper 

Missisrippi Valley mineral district fma Illinois basin brines. 

Econ. Geology, v. 81, p. 233-269. 

BETIME, C.n., 1986b. Roles of sediment empaction, tectonic conpression, 

and topographic relief in driving deep gmundrater migration. 

Gw~. SOE. Ilner. Ahstract with Prwms, v. 18, p. 

BLRTT. H., HIDDLFMW, G. and t4URRI.Y. R., 1912, Origin of Sedimentary

Rocks. Prentice Heli Ills., New Jersey, 6'31p. 

BLW. J-L. and IEUGR. 8.. 1986, Ths fracture of Hocks. elscvier, 

mstsrdam, 131p. 

BWUNT. O.N. and MOORE, C.H. Jr., 1969, Depositional and non-deponitle!t- 

a1 oarbanate brsccias, Chiantla Quadrangle, Guatemala. Ceui. Soc. 

Am?. Bulletin, v. 80, p. 429-442. 

EXGLI, A.. 1980, Karst hydrology and physical speieoloyy: Nev Yaru. 

Springer Verlag, 2Mp. 

BONW, L.C., 1980, Migration of hydmcarbons in capacting basins: 

mlsa, Oklahaaa. Pmr. Assoc. Pstml. Ealogy, Studies in Geology, 

V. 10, p. 69-88. 

BOSELLIWI, A. and W I E , L.R., 1973, Depositional theme 01 a marginal 

marine evaporite. sedbentology, v. 20. p. 5-27. 

BOSWM, H.H., WINO, L.U., WILLIRMS, H. and SNYTH, W.R.. 1983, 

Wlogy of the Strait of Belle Isle area, northwestern insular 

Newioundlend, southern Labradar, and adjacent puebec. Geoi. Surv. 

of Canada, Mmir 100, Map 1495n. 

BmCE, 1.0.. 1983, Preliminary OrdDvicien trilobite biohtraLigraphy ot 

the Eddies Cove West-Port eu Choix area, vastern Newfoundland. 

Mineral oevelop. Division, Newfoundland ~ept. ~linea and ~neqy, 

Report 83-1, p. 11-15. 

BOYCE, W.O., 1985, Wrian-Ordovician bloatretigraph~s investigat~ons, 

Great Northern Peninsula. Mineral Develop. Division, ~ewfoundland 

Dept. Mines and Energy, Report 85-1, p. 60-88. 

BOYCE, l.0.. 1986, Ordovician biaatratigraphic invealigations, rea at 

Northern Peninmula. ninsral Oevslop. Division, Nerlovndland Dept.

H~mn and Energy, Repor6 86-1, p. lbl-188. 

BMCK, W., 1968, The mvhanical ecfacts of pore pressure on fracturing 

of rock, Proceedings. Conference on Research in Tectonics, Geol. 

Surv. of Umedc, Papaper 68-5, p. 113-123. 

run 

BRADLEY, D.C., 1982, Subsidence in late Pal-ic bagins in the norl.hsn~ 

Appalachians. Tectonics. v. 1, p. 107-123. 

BUADLEY, D.C.. 1989, Mississippi valley-type PW4n mineraliaatlo!! during 

Ordovician arc-continent collision in the Appalachians, (abstr.1, 

Geologi~ltl Society of Pneeica Abstracts with Progrms, p. R8. 

SUEDEHOE?, J.D.; BACK, W. AND HWSHAN, B.B., 19B2, Regional grouad- 

*atcr flol ooncepts in the United states: Historial prr;psctlve. 

In: Narasinhan, T.N. led.) resent Trends in Hydmg~3olqly. Gml. 

w. mer., Spec. Paper 189, p. 291-316. 

BRIME. J., 1955, Disconfomity between In*er and Middle Ordovician 

Series at m g b Lake. Tennsssee. Geol. Soc. mr. Bulletin, v. 

66, p. 725-130. 

BRISXEY, J.A.; DINGESS, P.R.; SUI'CH, F.; GILBERT, R.C.; AMSTRONG, 

A.K and COLE. G.P., 1986. localization and source of Hississippi 

velley-type zinc dewits in Tenossrse, USA and c-risons with 

met. carbonifems mcks of Ireland. In: Andrew. C.J. et. ai., 

(pas.) ~eology and Genesis of nineral Deposits in Ireland. Irish 

As-. for Econ. Geology, p. 635-661. 

~nom, J.S. (ed.), 1961, Genesis of stratifom lead-zinc-barite-Cluorite 

deposits. Econ. Gwlogy, Hanograph No. 3, 44%. 

B-EY, H.E., 1951, crystal emvth. N ~ W ~ork. ohm wjloy and sons Inc.

571p. 

LAWLBS, L.M. and SMITH, 8.T.. 1983, Thermal constraints en ihe !=mi- 

t1on ol the Hississippi Valley-type lead-zinc deposits and the* 

imlications for episodls basin dsvstering and deposit genesis. 

Econ. Geology, v. 78, p. 983-1002. 

CAPPENTER, A.B.: TROUT, H.L. and PIWTT, P.E., 1971. Prcliaisary rrwrt 

on the orlgin and chemical svelution of iaod- and zinc-rluh brines 

in central Mississippi. Eson. kiogy, v. 69, p. 1191-1206. 

~ ~ ~ 0 P.A. 0 0 , and WILLIIVIS. H., 1986. wrthern extremity of the IlWer 

m AllochUlon in the mrtiand Craek area, westsr. Newfoundland 

and relationah1ps to nearby groups. In: Current Research Part 1, 

-01. Sum. of Canada, Paper 86-L4, p. 675-682. 

CAm,1D, LA.; WILLIIVIS, H. and WIm, .I., 1987, Geology ol mrtiilnd 

creek aree (12 114). western Newfoundland. Geir. Surv. of Canada, 

Open File 1435. Scale 1:50,000. 

W D , P.A. and WILLIPIMS, H., 1988. Rcsdien hasmnt thrustins, crustal 

delamination and structural styles in and emund ~ h Humher o nnn 

Riiochthon, western Newfoundland. Geology, v. 16, p. 370-373. 

cnwwo, P.. r1LLIIVIs. H., O'BRIEN, S.J. end O'NEILL, P.P., 1988, Trip 

Al. a gealqic ems-section of the Appalachian Orogen. Field Trip 

~uidabwk. ~eological ~svociation of Canada Annuat Meeting. St. 

John's, Nfld. 

CHILINGPX, G.V.; ZENOER, D.H.; BISUL, H.J. and WOLF, K.11.. 1979, 

cotmites and miomitieetion In: G. Larsen and O.V. Chliingar 

(eds.) ~iagenesls in sedbents and Scdimntary Rocks. Elsavicr. 

Amsterdam, p. 423-536. 

'."I

nmpuFTm, P.W., 1971, Late ?err-n dolamite cement. Nisrissippiaa. 

carbonates, lilinois Basin, U.S.A. In: Brlcker, O.P. led.) Car- 

50' 

hate Cnaente. The John's Hopkins Usiversity Studies in C~alogy, 

IM. 19, The John's Hopliins Press. Beltinare, p. 139-346. 

MapuEma, P.W. and PWLY, L.C., 1970, Geaiwic noo~snclature and 

classification of porosity in sedimntary csrbonetca, Bvllatin oP 

the american As-. nf Pstroleum Gwl., Vol. 51, p.207 - 250. 

cnopuETT8, P.W. and JIUIES, N.P., 1987, Diagenesis 12. Diegenesis in 

limestones -3. The deep burial envimrunent. Gwsoience Conade, v. 

14. p. 3-35. 

MOW, N., 1986, Sedimentology and diagenesis of Middle end Upper 

Cdrien platform carbonates and siliciclasticn, Port su brt 

Peninsula, western Newfoundland. Unpubl. Ph.0. thesis, Hemriel 

University of Neufmndhnd, 458~. 

cms, T.n. and ELKINS, J.E., 1971, The origin of quartz geodes and 

csuliflwer chert. thmugh silicification a€ anhydrite nodules. 

Jar. Sed. Petmlqy, v. 44, p. 885-903. 

nsNE, J.L., 1985, ~epth dependrnt sedimentation and the flexural edge 

effect in epciric seas: measuring natw depth relative to the 

lithosphere's flexural wavelength. Jour. Goology, v. 93, p. 567- 

576. 

CISNE, J.L.: GILD^, R.F.; and IUBE, B.D., 1984, Epeiric sedimentation 

and sea level: Synthetic ecostratigraphy. Lethais, v. 11, p. 267- 

288. 

CULYPWL, G.F.; HOLSER, W.T.: IIILPUII. I.R.: M I , H. end ZRU, I. 1980, 

The age curves of sulfur and omen isotopes in marine sulfate and

their nutllnl interpretation. Chemical cmlqiy, v. 18. p. 399-2611. 

CMYTUN, R.N.; JONES, B.P. and ULRNER, R.A., 1968, Isotope studieo of 

dolomite formation under sedimentary conditions, Geoolrim. ot 

Coslbxhb. Acts, v. 32, p. 415-432. 

COLLINS, J.A., 1971, Cartatate lithofacies and diugenesis rclaLed Lo 

sphelerite nineraliration near Uanlalas Harhour, western New- 

foundland. Unpubl. LSe. thesis, puefn's Ilniversiry. 184~. 

WLLINS, J.A., 1972, Sphalsrita as leiated to the tecLon~c ~avments, 

lim 

deposition, diagenesis and karstification of a carbanate platfom, 

Proceedings of the 24th Intarnational ~eological Congress, 

nontreal, section 6, P. 208 

COLLINS. J.I. and SHITH, L., 1972, Lithostratigraphis contmla: of sane 

Ordovician aphalerite, in RHSlUTZ,G.C. and DERNaRO, A.J.. (eda.1. 

ores in Sedhents, Sprlnger verlag, Heidelberg, p. 79 -91. 

WLLINS, J.A. and RIITH, L., 1975, Zinc deposits related w diagenesis 

and intrskarstis aadimentetion in the Lower Ordovician st. Ceoqe 

Formation, western Newfoundland. Bull. Can. Petrol. Gwlqiy, v. 

23, p. 393-427. 

CONIGLIo, M., 1985. Origin and d;ageneais of fine-grained slope sedi- 

ments: Cnr Head Group (Cdm-Ordovician), western Newfoundland. 

unpubl. Ph.0. thesis, rnnarial University of Newfoundland, 684~. 

WNIGLIO, H. and JmS, N.P.. 1985, Calcified algae as redbent can- 

tributors to 6arly Paleozoic lh.estane+: evidence fm deep water 

sediments of the Cnr need Omup, western Newfoundland. Jour. or 

Sed. Petmlogy, v. 55, p. 746-754. 

WE, R.B., 1969, Report of work done by Cminco on Leitch Conccrslons

Daniel's Ilarboar. western Newfoundland. Unpubl. reprt. 

CURON. C.R.. 1982. Faciea relations and ore genesis of the Newcmdlard 

nine mines deposit, Daniel's Harbour, western Newfoundland. 

Unpubl. Ph.D. thesis, Univsraity of Tomnla, 16Ap. 

COWAN, C.A., WLLY, W.C. and WILKINSON, B.H., 1985. "Cwnteii" Iluorltc 

rhythmites of southern Illinois: evidenca [or episodlc basin 

deuatering, Geological B, ~ety of mrice, Rbrtracta with 

Pt'ogrmS, Y. 17. p. 554. 

504 

CWLIG. J.R. and VAUGHIW, D.J., 1981, Ore Mineralogy and Ore Petrography, 

Wilry Interscience. 409p. 

CRAIG, J.R.; SDLBERT, T.N. end VAUmN, D.J., 1983a. Compositional 

variations in sphalerite ores of the East and Central TenneEsea 

zinc distriott. In: Craig J.R. ieri.) Tennesse zinc deposits Eleld 

trip guidebaok. Viminis Tech Dept. of G~~lqloal Sciences, 

Guidebwk No. 9, p. 152-164. 

CRRIG. J.R.: SOLEERG, T.N. and QAUGHPJI, D.J., 1983b. Gmwth characteris- 

tics of sphalerites in Appalachian zinc deposits.' In: Kisvarsanyl, 

G.; Grant, S.K.; Pratt, W.P. and Koenig, J.w. leds.) Proceedings 

vollune. Internstbnal Conferenve on tiissiaeippi valley-Qpc lead- 

sins deposits. Univ. Missauri-Rolle Press, Ralla Missouri, p. 3:'l- 

327. 

CUMING, L.I., 1968. St. Georqe-Tabla Head di-fclmity snd zinc 

mineralization, restern Newfoundland. Canadian HininS and Wstel- 

lunjical Bulletin, v. 61, p. 721-725. 

o m n , R.D.. 197:. ."arlx'ar spectra a€ minerals frm the $1-r dc 

Lyr terrane in northwest Newfoundland: their bearing on chronology

cvf metanorphirm within the Rppalacltian 0rthoLectonie zenc. .lour. 

of Geology, v. 85. p. 89-103. 

DmEYER, R.D. and HIQBRRD, J., IW, rrachhronoioqy of tho Boie Vcrtc 

Pnninsulc. Newloundlend, i~nplications tor Lhe Lactonic evolution 

,505 

of the HMcr end Dunnage Zones ot the ~ppalscllian Orogen, Journal 

OF Oeolugy, v. 92, p. 489 - 512. 

DALRYHPLE, R.W; NRRWNNE. G.N. and SMITH, L.. 1985, Eolian action and 

the distriblltion of Cambrian shales in North hrica, Ucoiagy, v. 

13, p. 607-610. 

DESROCHERS, A,, 1985, The Lower and Middle Ordovician plslfolrn car- 

bonates oi the Mingan Islands, puebec: stratigraphy paieoknrnl end 

limesto08 diageoesin. Unpubl. Ph.D. thesls, n~rorial University al 

Newfound-land. 342~. 

DEVOTO, R.11.. 1985, Sedimentoiogy. dolamitiration and minsralieat~on of 

the Leadville Lhsstone (Mitsissippiao), centre' Colorado. Guide- 

baOk for .%. Beon. Peleon. Mineral., Fisld '71'1:~ No. 6. SEPM 

Midyear Meeting Mldsn, Coloredo. 

DILLON, E.P., 1918, A multi-element geochmisai study of thc pwudobmc- 

cia host m& of the Newtaundland Zinc Nine. Vspubl. M.Sc. Lbesis, 

University of Toronto, 31p. 

OIBN&X, J.R.; GIUDIIER, 6.; W I N , A. and l'R1CHF.L J., 1986, Rarly 

biodegradation of ligneous organic materials and its relatian Lo 

ore deposition in the Treves Zn-Pb ore body (Gard. Prance). 

organic Geochemistry, v. 10, p. 1005-1013. 

DIXON, B.E.L. and VAuGtVur, a,, 1911. The Carbonifemus succession in 

W;cr (Ql-reanishire), rich nctes on its fauna and conditions of

drp*ition.,?uert. Jwr. cwi. w iety, v. 67. p. 1'17-567 

DIXON, J., 1976, Patterned carbonate - a diugnetic foalure. 8uli. Con. 

Petrol. Geology, v. 24, p. 450-156. 

lillt. 

DOE. 14.0. and mm. R.E., 1919. ~lumot~ct~nic~, rllv ~han~~ozoic. in: 

Barnes, H.L. (ed.) Gemhamistry of hydrothclroal ore deposits. John 

Wiley and mss, p. 22-70, 

03m, E., 1976, CeyStal structure nnd clystai gmwth: IT. Sector zoning 

in minerals. her. Mineralogist, v. 61, p. 4MI-469. 

DUNNIlili, R.E.; KROGH, T.E.; O'DRIEN, S.J.; WWN-SADD, S.P. and 

O'NEILL, P., 1988. Geochmnologic framework Eor the cenlral Mobile 

belt in southern Newfoundland and the importance of Liilurian 

hxJeny lebatr.). In: Pmgram with abstracts, v. 13, Annual 

meting of Geol. Pssoc. Canada, p. h34. 

DUNNING, G.R.; O'BRIEN. S.J.; WLMAN-SAW, S.P.; O'NEiLL. P.P. vlld 

KROGH, T.E., In prsss, Silurian omgeny In Newfour.dland. dour. of 

Oeoiagy. 

DUNSMORE, H.E., 1973. ~ir.genetic pmcoaser of lead-zinc wplacernent in 

ca~bomtes. Inst. Mining netall. Bulirtin, v. 02, p. 9-13. 

DZ~L~SKI. s. end SASS-GUSPKIENTCZ, H., 1986, Hydro:heml karat 

phsnmna as s factor in the fomation of Mississippi valley-type 

depslts. In: Nolf, K.H., led.) llandbook of Strata-bound and 

st:atifom Ore Depitn, v. 13, elsevier hst.trdam, p. 391-439. 

eesr~s, H.L. and YOPP, o.c., 1979, Cathodolunineseent microstretlgraphy 

in gangue dolomite, the Mascot-Jsfferson City district, Tennessee. 

Bcon. Geology, r. 74, y. 908-910. 

Q(DIILS, A.A.; BRWLY, R.G. and PEnBERmN, S.G.. 1984, iclmoiogy: the

507 

use aE trace fossils In sedlmentolcqq strotigrilplsy. SW. con. 

Pnleon. Miner. Short coursr NO. 15. 

ELLIOT, 0.. and JOHNSON, M.R.W., 1980. The structural evolulinn of Lho 

northern part of the Noine thrust zone. noyrri sacicty Edinhvrgh 

Trans. Ear. Science, v. 71, p. 63-9b. 

F-THINGTON, R.L. end CWLRK, D.L., 1971, Laver ordovieten conla"-*ts in 

NorUl lunerica. Ceol. Sa. lunar., Mensir 127, p. 61-82. 

ETHINOMN. R.L. and CUM, O.L., 1981, her and niddle 0ldovil:lan 

mdonta f m the Ibex area, veatern Millard County, ULah. 

Brishm Young University Gcolcqi Studies, v. 28, Part 2. 160p. 

ETHRIEGE, P.G.; ORTII, N.V.; GPWGER, H.C.; FZRENTMM, J.A. and SUNN),?, 

D.K., 1980, Effects of gmund-water flow on the crigin or Colorado 

Plateau-type uranium deposits. In: Mew Mexico Bureau of Mincs and 

Mineral Reeoumes, Mmir 38, p. 98-106. 

EVUdS, C.R.; ROGIIRS, M.A. and BAILEY. N.J.L., 1971, Evolulion and 

alteration of petroleum In western Canada. Chm. Geology, v. 8, p. 

147-170. 

F&RLEus, L.E., 1970, mnodont-bared corrciatlons of Lwer an6 niddle 

Ordwlcian strata In western NeuEwndland. G-I. Soc. Nns-. 

Bulletin, v. 81, p. 2061-2076. 

FINNEY, S.C., and S~VINGTOI, D., 1979, A mimd Atlantic-Pacific 

provincr, Hidale Ordovician graptalite fauna in western Neu 

fmndland. Con. ;lour. Earth Ssiencs, v. 16, p. 1899-1902. 

FIscriEn, A.G., 1964, The Lafer cyclothmns of the Aipine Trii#wic. Bull. 

-01. SOE. Kansas, V. 169. p. 107-149. 

FLUGEL, E., 1982, Micmfacies malysls of Llmastonan. Springor-Verlag,

New 'fork, b33p. 

POLBY, N.K., SINWI, A.K. and CRAIG, 3.R.. 1981. Isotopic canpaition or 

lead in the nustinvillr-Ivanhoe Pb-Zn district, Virginia. Rcon. 

Oeology, v. lb, p. 2012-2017. 

qnu 

FOLK, R.L. and ASSER'm, R., 1974, Giant areyoolto reys and baroque while 

dolomile in tepee-Fiilisrjs, Triasaic OF Mardy, Ilaly (abstr.). 

mer. ASSOC. Patml. Geologiah. Rbstrasts with Pmgra. Annual 

Nesting San Antonio. p. 34-35, 

EVLK, R.L. and m, L.S., 1975, Mglgjca ratio and salinity: two controls 

over crystallization oE dolomite. mr. Assac. PeLml. Oeol. 

Bulietin, v. 59, p. 60-68. 

FONTBOTE, I. and MSPUTZ, G.C., 1983, Diegenetic crystaliization 

rhythites in Mianisrippi Valley-type ore deposits. In: Kisvar- 

sanyi, G.; Grant, s.K.; matt, W.P.; and Koenig, J.W. la.ds.) 

Praseedings Volume-International Conference on Hissisrippi valley- 

type lead-zinc deposits. Univ. Hisswri-Rolla Press, Rolla His- 

souri, p. 328-337. 

FORD. D., 1988, Chlvcicteristics of diesaivtio~l save systems in 

oarbanate rmks. In: Jamas. N.P. and Chouquette, P.W. (eds.) 

Paleekarst, NBV York, Springer vsrlsg, p. 25-51. 

FORTEY, R.A., 1919, Early OrdovieIan trilobites F mm the Catoche 

Formation (St. Gcorge Group), western Newfoundland. M i. Surv. of 

cancda. Bulletin 321, p. 61-114. 

PORTEY, R.A., >!4, Glohal earlier Ordovician transgressions and 

regressions and their biological Implications. In: D.L. Bruton 

fed.) Aspects of the Ordovician System. Pelwntolcqical mntrib.

Elm the University of 0610. Univcrsitebforlaget 295. p. 37-50. 

FWWK, J.R.; CARPENTER, A.8. and OGLESBY, T.W., 1981, Cathodolumincs- 

509 

crncr and c-sition of calcite cmnt in the '~aum savk ~imcstanc 

(Upper Cambrian), southeast Missouri. Lour. of Sed. Pelmlogy, v. 

39, p. 1438-1454. 

M S . 8. and HIRESTPR, R., 1984, Relationships amng secondary 

porosity, wro-fluid chemistry, and COX, Texas, Gulf coast. mcr. 

Assoc. Petml. Geology, Mmir 37, p 63-80, 

FRESHPIN, T., 1912, Sedimentology end dolamitieation of Huschelkalk 

carbonates (Triassic), Iberian Range. Spain. Bull. Wr. As-. 

Petrol. Geology, v. 59, p. 60-68. 

IREEXPJI, T., and MBDIIRY, T., 1987, Modification of precursor dolostone 

by a later dolonitiring event: the Sanneterre Formation (cm- 

hrian), southern Missouri (abstr.1. In: Sac. Econ. Paleont. 

Mineral. Annual Midyear Meeting ahstrecta, p. 28. 

FRIEWX. 6.1.: 1965, Terminology of orystalliration textures and 

fabrics in aedimentzy m&s. Jour. Sed. Petrology, v. 35, p. 643- 

655. 

FFSEMUVI, G.M. and SAUNDm, J.E.. 1961. Origin and occurrence of 

dolostones. In: Chiiinger, G.V.; niaaell, H.J. and Fairbridge, 

R.W. (ads.) Cartonate Rocks. Origin, Occurrence and Classifica- 

tion. Elsevier, msterdam, p. 261-348. 

FYFE, W.S.; PRIO3, N.J. end THOMPSON, R.8.. 1979, Fluids in the Earth's 

Crust, Developnts in Gewhhmistry 1. Elsevier, 383p. 

GAINES. A.M., 1974, Protadolmite synthesis at 100°C and amspheric 

pressure. Science, v. 183, p. 518-520.

CaINES, A.M., 1980, Dalmitieation Kinetics: recent experlmcntal 

310 

stud~es. In: Zengur, D.H.; Dunha, J.R. and Erhington, K.L. (cds.1 

Concepts and Models of Dalmitisation. Sac. con. Palcan. Minerttl. 

Spec. Publ. 28, p. 81-86. 

WLWaWAY, W.E., 1984, Hydregeolegic regimes or sandstme dingenesir. In: 

PcDonald, D.A. and surdam, R.C. (cds.) elastic Diagenssia. ar. 

Assoc. Petml. Geology, "emir 31, p. 3-14. 

WLRVEN, G., 1985, he mle of regional fluid flow in the genesia d the 

Pine mint deposit, Western Canada sedimentary basin. Econ. 

Geology, Y. 80, p. 301-124. 

GARVEN, 0. and FREEZE, R.A., 1984a, Theoretical analysis of the role of 

gmundnater flov in the gene.1. a€ stratabound ore deposits. 1. 

Mathemtical and numericel models. Am.. Jour. of Ecience. v. 284, 

p. 1085-1124. 

GARWN, G. and FReEZE. R.A., 1984b. Thwretissl analysis uf the rals of 

groundwater flow in the genesis of stratabound ore deprits. 2. 

Quantitative results. mr. our. of science, v. 2HI, p. 1125- 

1174. 

GPRW, G. end SWJEN0KY. D.A., 1989, Hydmgeolegy o€ regional flow 

systems associated with the formation of Mississippi velley-type 

ore deposits in the mid-continent, (abstr.), Geological Society of 

msrica mdractr vith Pmgrm, p.119. 

~ O R P B R.L., , 1987, Burial doimitizarion and porosity devel-nt in 

a mixed carbonate-clastic sequence: en exqle fro. the Barland 

Basin, northern England. Sedimentalogy, v. 34, no. 4, p. 533-558. 

GAYLOW, 1.0, and BRISKEY, J.A., 1983, Geology of the Ehod and

Gordonaville mines, central Tennessee zinc district: l'enncssce 

zinc deposit field trip gulde bouk; vlrginia I~iytrshrric Inrti- 

tute. Blacksburg, Ve., ~uidebok 9. 

GOW33AlMZR. R.K.; DUNN. P.B. and HRROIE, L.A.. 1987, Iligh freluency 

glasio-eustatic see1 level osciilationr with Milenlmvltch cham- 

teristics racorded in Niddle Triassic cyclic platfom carbomter. 

northern Italy. Imer. Jour. Science, v. 287, p. 853 -892. 

GOLDSMITH. J.D. and Gw, D.L., 1958. ~elatiun between lattice sonrtenta 

and -position of ths Ca-19 carbanates. mr. Nineraiagist, v. 

41, p. 81-101. 

GmTZ, 3.). and MIsnn, K.C., 1981. Fluld iclclusion study d the Gar- 

donaville zinc deposit, central Tennessee. Econ. Geology, v. 82, 

p. 1190-1804. 

omo, J.M., 1985, ~egional epigenetic dolanitiaation in the nonneterre 

Dolanite (cmrian) southeastern nismuri. ~eology, v. 13, p. 503- 

506. 

ma, J.M. and HIIGNI, R.D., 1981. Irrlgular ssthodoiwinsscent banding 

in lets dolnrite cmnts: Evidence for oonplex fsceting and metai- 

liferma brines. Gwlogissl Ssiety of America Bulletin, v. 98, 

p.86-91. 

GREGG, J.M. end SIBLBY, D.F., 1984, Epigsnetic dolomitiP.stian and the 

origin of xenotopic dolmnits texture. Jour. Sad. Petrology, v. 51, 

p. 908-931. 

GRENIER, n., ass, me Appslachian fold and thrust belt, northwest 

~awfoundland, unpublirhad m.6~. theds, Newrial University of 

Nevfoundland, St.JohnSs.

GRBNIER, R. and C A W , P.. 1988, Variatims in rtruclural style along 

the long Range honr, western ~evfmndland. 11,; current Hcscoroh, 

Part 8. Geol. Surv. of Cenads. Paper 83-18, p. In-133. 

GREmER. P., 1969. Pluid prersure in porous mdia, its importance in 

geolwy: a review. Can. Petrol. Geci. Bulletin, v. 17, p. 255-295. 

GRFPBNER, P.P., 1981, Pore pressure: Fundanmtals, general rmlitica- 

tions, an implications for structural geoloqy (revised). mr. 

ASSOF. Petrol. Geology, education Caurre Note Ssries No. 4, i31p. 

GRIPPITBS, R.W., 1981, Layered dwble-diffusive convection in poroua 

media. Journal of Plaid Mechanics. v. 102, p. 221 -248. 

GRWM. R.M., 1949, Strusturea due to voluae ahrinkage in the bedding- 

replacenrnt fluorspar deposits of Southern Illinoir. Dmn. Geol- 

ogy, v. 44, p. 606-616. 

,i l? 

GROTZINGER, J.P., 1986, Uprald shallwing plstfom cycles: a rorponse to 

2.2 billion years of lor-rtmplitude, high-frmqvency (Wilankovitch 

band) sea level ossilletions. Pal~coanagrephy, v. 1, p. 403-416. 

GRuTwNm, J.P., 1986, Clslioity and pal-nvirorunenta& dynamics, 

~ocknrst platform, northwest Canada. Geol. Soc. mer. Bulletin, v. 

91, p. 1208-1231. 

GROVER, G. Jr. and m, J.P., 1978, Peneatral and associated vadose 

diagrnetic fabrics of tidal Eiar carbonates, niddls Ordovician Neu 

mrket limestone, southwestern Virginia. Jour. Sed. Petrology, v. 

48, p. 453-473. 

GROVER, G. JZ. end Rm, J.P., 1983, Pilleoaqvifee end decpburisl- 

related cmnte defined by re4ione.l cethodoluminesscnt patterns,

5LJ 

Middle Ordaviclsn carbonalen, Virqillis. bull. met. nssoc. Petrol. 

Gmlogy. V. 61. p. 1275-1303. 

GRUNDWIWN, W.H. Jr., 1917, Gmlogy of the Vibur~~un No. 2'1 Mine, Vibamnm 

Trend, Southeast Missouri. Econ. Geology, v. 72, p. 319-364. 

GULSON. B.L.. 19S5, Shale-hosted lead-zinc depoaits in northcrn htstral- 

ia: Lead isotope variations. Eeon. Geology, v. 80, p. ZUUi-2012. 

GULSON, B.L., PERKINS, W.O., and MIWN, K.J., 1983, Lead iaotopc studies 

baaring on ths genesis of copper orebodies at Mount Iss. Queens- 

land. Econ. Geology, v. 78, p. 1966 - 1504. 

WAS, J.L., 1976, fiernodynmis properties of the coexisting phases and 

themchemical pmperties of the li,0 cmponant in balling NaCl 

soiutions. U.S. Geol. Sum. Bulletin 1421-8. p. 1-71. 

HRGNI, R.D., 1983, Ore microscopy, paragenetic sequence, trace elsaent 

content and fluid inclusion studies of the copper-lead-zinc 

deposits. I": Kiavarsanyi, 0.; Grant, s.K.; ~ratt, w.P.; ~oenig, 

J.H. (eds.) Proceedings Volume, International conference on 

Mississippi Vellcy Type Lead-Zinc Deposits. Univ. Nissmluri-Rolla 

Prcrs, Rolla Missouri, p. 243-256. 

HPLL, C.H., YORK, D., SRUmERS, C.M. and STRONG, D.P.. 1989, Laser 

"'ar/"*n'ai dating of Mississippi Valley Typs mineralization from 

western Newfoundland, (abstr.), Abstracts 28th International 

Gmlogical Congress, v. 2, p.10. 

HaLL, W.E. and P R I m , I., 1963. coloporition of fluid inclusions, 

Cave-in-Rock fluorite district, Illinois, and Upper nilissippi 

valley zinc-lead district. won. Geology, v. 58, p. 006-911. 

HRLLEY, R.B., 1987. Burial diegenesis of carbonate rocks. Colorado

Scl~uol of Mines Quarterly. v. 82, p. 1-15. 

'1!1, 

HUWOR, J.S., 1919. The vedimentary genesis of hydrolhemill Iluidr. Is: 

Barnes, H.L. led.) Gemhemistry of hydrotherroal ore depusits, r' 

rd: New YOrk. Johll Wilsy end Sons, p. 137-112. 

HANSHAW. 8.C.: BACK, W. and DEIW, R.G., 1911, h geochemical !hypot!losir 

for doimitizarion by gmundmter. emn. Gwiogy, v. bb, p. 710- 

724. 

HARDIE. L.A., 1986, Stratigraphic models for carbonate tidal Elat 

deposition. Colorado Schwl of Mlneo Quarterly, v. 81, p. 59-74. 

HmIE, LA., 1981, Dolomitiration: a critical view at soma current 

vie . .lour. sed. Petrology, v. 51, p. 185-202. 

HIUIDIE, L.,,.; BOSELLINI, A. and GOLMIMER. R.K., 198b. Henaated 

subaerial exposure of mbtidel cartenate platform, Triassic, 

northern Italy: evidence for high level frequency sea level 

oscillations on a 104 year scale. Pal-eanography, Y. I, p. 441- 

451. 

WIS. 1.0.. 1979, Cmodont color alteration and orgeno-mineral 

metamorphic index and its application to Applashien Uedsin 

geology. In: S~halle, P.R. and Schluger. P.R. (eds.1 Aspects or 

Diagenasir. Sw. Ecoa. Paleon. linerel. Spec. Publ.. v. 26, p. 3- 

HAYWICK, D.W., 1984, mlomite within the St. Gwqe Grmp (Lower 

ordwicim), Mestern Newfoundland. Unpubl. H.Sc. thssis, Urnrial 

University of Nwfmndiend, p. 

HILYwICK, D.W. and JIUleS, N.P., 1984. Dolomites and dolomitization of the 

st. George Gmup (Lover Ordovician) of western Newpoundland. In:

cmront uesest~h, part A, cmi. sum. or uvlada. P : , ~ AOIA. ~ ~ P. 

531-536. 

~IECKEL, P.H., 1972, ~oaslbls inorganic origin rur sttanatoctis in 

calcilutite mundr in the l~lllly Lin~estone, orvonian ol New York. 

Juur. Sed. Pe:mlogy, v. 12, p. 7-18. 

515 

HEUiESDN, H.C., 1969, Th~mdynmics of hydrothermal ryelams at elevated 

tWpelatUTeS and PreSSUreS. he.. Jour. ol S~icnca. V. 269. P. 

129-804. 

nwr, n.v., 1983, G-logic characteristics of thrca major uississippi 

Valley districts. In: Kisvarsanyi, G.; GrsnL, s.I.; Pralt, W.P. 

and Xosnig, J.W. Pmccsdings Valum. International CanEerenco on 

Mlssisrcippi Volley Type Lead-zinc Uepasits, Univ. Missouri-mila 

Press, Rolla Hissouri, p. 27-59. 

HEW., R.V.; LDNDIS, G.P. and 'LARTIUW, R.E., 1971, Isotopic evidence lor 

the origin of Mississippi Valley-type mineral deposits: a revlev. 

emn. Owlagy, v. 69, p. 992-1006. 

HIBBU(D, J., 1983. G~logy OP the Baie Verte Peninsula, Newfoundland. 

#emir 2, NCwfWndland Dept. Hinea and Energy, Mineral 0evr.i. 

Division, Newfoundland. 279p. 

IIINTZE, L.V., 1952, Laer Ordovicisn trilobites from western Utah and 

eastern Nevada, Utah. Geological and Mineralogical Survey Bull- 

etin, 48, 219p. 

HISWW, R.N., JWS. N.P. and PEUBERTON, S.G., 1984, Sedimntolaly and 

ichnology of the m r cabtian &ahre Formation: Fluvial to 

~hallw marine transgressive reymsnsf, coastal Labrador. Bulletin 

of canadian petroleum Geology, u. 32, p. 11 -26.

HITCHON. 8.. 1969, Fluid flow in western Canada sedimertary basin. I. 

effect of topagraphy. water Resources Researoh, v. bll), p. lab- 

195. 

HITWON, 8.; BILLINGS, G.K. and KraVW, J.R., 1471, Gcoct~eolistry and 

origin of fomtion waters in the Western Carladion sedimentiwy 

baain - IiI: Factors conmlling chemical cmpmsition. oeochim. cl 

cosmchim. ncta., v. 35, p. 567-598. 

HOncLAND, a.0.. 1976, Ilgpalaohian zinc-lead depsits. In: K.H. Wll 

led.) Handbwk of stratahaund and stratifom ore depaaits, v. b, 

Chapt. 11, New York, Elsevier, p. 495-534. 

HmGWWD. 1.D.; HILL, W.T. and IULWEILER, R.R.. 1965, Oenssir ot thc 

Ordovician zinc deposits in east Tennessee. =con. Gmlogy, v. W, 

P. 693-714. 

HOEPS. J., 1980, Stable Isotope Gwchemietry. Berlin, Springer Vcrlag, 

20Q. 

HOLWWO, H.D. and WNIN, S.D., 1979, me solubility and accurrense of 

"on-ore minerals. In: sarnes. H.I. (ed.) ~mhimistry of Hydm- 

thermal Ore Deposits, 7'" ed. New York, Wlley-lnterssien~c, p. 

461-508. 

HOLLISTER. L.s., 1970, origin, mechanism and cunsequencen oE cqoni- 

tional sector-zoning in Steurolite. mr. Mineralogist, v. 55, p. 

742-766. 

WRTON, R.A. ~r., 1985, ~olonitization oE the Lsadville limrtone. In: 

Devote, R.H. (d.) sedimtoiogy, Doidtiaatiol,, Karstlfioatian 

and ~ineraliratian of the Leadville LInestone IMisissippian), 

central colorado. SEW Field Trip No. 6 Guldeboak, SEPn Annual 

!I,,>

Midyear neqing, Golden Colorado, p. (6)51-(6)70. 

HUBBERT, M.K. and WILLIS, U.G., 1957. M-hanlcs oI lhydrn~nllc rrosturlng. 

Petrolem transsctiona, AIHB, v. 210, p. 153-163. 

HUTCHWN, I.; OLOeRSHIN, A. and CHEW, e.0.. 1980, DLagenesix or 

Cretilceous sandabneb of the Koatenay Fo~matirul st Elk Valley 

(southeastern British Columbia) and Mt. Allsn (eouthwestern 

Alberta). Geoshh. et Cosmhim. &la, v. 44, p. 1425-1635. 

WE, R.S., 1979, Geology d Carbonifemus strata in portions of thc 

Deer Lake Basin, waster" Newfoundland, Newfoundland and Labrador 

Departrent of Nines and Energy, mineral Development Ulvlsio!?, 

Report 79-6, 43p. 

Hm, R.S., 1983, Geology Df the Carboniferous Deer Lake basin. Naw- 

foundland Dept. of Minas and Energy Mineral Oeval. Division, Map 

82-7. 

tMIE, R.S., HILLER, H.G., HISCOW, R.N. AND WRIGHT, J.A., 1988. Basin 

srchitwture and them1 nlaturation in the strlke-slip Deer Lake 

Basin. Carboniferous of Newfwndland, Basin Rekearch, v. 1, 

IUIINO, L.V., 1959, Depmition and dingenesis of s m upper Paleozoic 

carbonate sediments in western Canada. In: Qmceedings. World 

eet?olam congress, 5"', New York. Secl., p. 23-52. 

IHBRIE. 4. and IHBRIE, J.Z., 1980 #&ling the clinetic resmre Lo 

orbital variations. science, v. 207, p. 943-952. 

I W ~ w.T.. . 1951, The ~luebell Nine. In: Structural Geology of 

cansdian ore Deposits Vol 11. b'." Camnonwealth Minmg end Metal- 

luzgical Congress, p. 95-104. 

511 

Imm, T.N., 1980, Magmatic infiltration Retamatism, double diffusive

fra~tion&l'eryatallisatlon, adcwlur growth in the Musk Or and 

?In 

other layered intIu9iOnS. in IIARGRRVES. R.S., (ed.) Physics ot 

Hamatic Procesaaa, Princeton University ~rcss, IPrinoelo~~, N.J., - 

P. 325 -383. 

IRWIN, H.L., 1965, General theory d eperrlc cicer water sodlmcntotios. 

Bull. Ilmer. Assoc. Petrol. Geolrgy, v. 49, p. 145-459. 

JACK^, S.A. and BaUBS, V.W., 1961. A" aspect of sedimentary basin 

evolution: The concentration of nississippi valley-type ores 

during late stages of diagenesis. Canadian Petml. -01. Bulletin. 

v. 15, p. 383-433. 

JRmBI, R.D., 1981. Peripheral bulge - e causal mechanism Eor the 

lauer/Middle Ordovician unmnforaity along the western lnargin of 

the Northern Appelachians. Earth and Planerary Science Letters. v. 

56, p. 245-251. 

JMS, N.P., 1984, Shallming-upward sequences in oarbonetee. In: R.C. 

walker led.) Pecies Models. Geoscience Canada Reprint sedes. No. 

1, P. 213-228. 

J ~ S N.P. , and KULPPA, C.F., 1983, Petrogenssis of Early Cdrian reef 

limestones, Labrador, Canada, Journal of Sedinentary Petrology. v. 

5'9, p. 1051 -1096. 

JMS, N.P. and STWENS,R.K., 1986, stratigraphy and correlation of the 

cow Heed ~ mup (Wro-Ordovician), western Newfoundland. Geol. 

Sum. of Canada Bulletin, v. 366, P. 

~ m s , N.P.; KNIGHT, I.; STEVENS, R.K. and EWES. C.R., 1988, Scdlmcn- 

tology end paleontology of an early Paleasolc continental margin, 

western ~evfoundiand, Trip BI, field trip guidebook, Geol. Asaa;.

Canada Annual Meeting. st. john's, Newloundiand, 121 p. 

JmS, N.P.; BILRNES, C.R.; STEVENS. R.K. and KNIGHT, I., 1989. A Lower 

!>I9 

Pdleoz~ic continental margin earbooate platform. northern Canadian 

Appalachians. In: T. Crevello, el. ai., (eda.) Controls on Car- 

bonate Platforms and Basin Oevelopnent, S EW spec. Publ. 14, p. 

123 - 116. 

JENNINGS, J.N., 1971, Karst: An introduction to systematic ge-rphol- 

ogy. Australian National Univ. Press. Canberra. 252p. 

JI, 2.. 1989, Loner Ordovician conodonts of the st. George Group oI Part 

au POIt Peninsula, western Newfoundland, unpublished Ph.0. thesis, 

Mmrial Univarsity of Newfoundland. 

JWRY, R.L., 1969, G mth and d~lomitization of Silurian reefs, SL. 

Clair County, Hichigen. mer. As-. Petmi. Geol. Bullrtin, v. 

53. p. 951-981. 

JONES, 8.; OWERSNAW, A.E. and NNONNE, G.M., 1919, Nature and origin 

of ~ bbly limestons in the upper Silurian Read nay Porntion OF 

-=tic Canada. Sed. Ceology, v. 21, p. 221-252. 

KELLY. W.C.; RYE, R.O. and LIVNAT, A,, 1986, Saline nine waters of Lhe 

~eveenav mninsula, Northern Michigan: Their nature, origin end 

relation LO similar deep waters in Precambrian crystallinr mcks 

of the canadian Shield. mr. Jour. Science, v. 286, p. 281-3011, 

m s m , s.E., 1989, evolution of Hississippi Valley-type (HVT) brines in 

bwer ordovisian carbonate msb of the Appalachien Orogen, 

(ebstr.), ~wlogigisal w iety of mrica Abstracts with Programs, 

p. A8. 

m m m , A.c., 1984, Evaporite.. In: Walker. R.G.. (ed.) Pasles Hodels.

Geol. bsac. of Canada. Geosclence Canada Reprint Series I, p. 

259-298. 

v,ZII 

KENDULL, C.G.L.S. and SKIPWITH, P.A.O'c, 1969, lloloccnc shsllar-walcc - 

carbonate and evaporite sediments or Khoc "is Uorm Abu Ilhabi, 

~o~th~est Persian Gull. Bull. her. hssoc. Petrol. Gmiqy. v. 51. 

p. 841-869. 

KeNDPILL, D.L., 1960. O m dspaaits and radhcntary Ceatures, Jeftcrson 

city nine. Tennessee. con. ~eolagy, v. 55, p. 985-1003. 

m m , Y.K.; UROTHERS, W.W. and mrsrNnnlaa, R.J., 1983. he mi 

decarboxylation of acetic acid: implications for origin of natural 

gas: -hh. et Cosmhim. Rcta., V. 47, p. 397-402. 

Mmnm, Y.K.; HULL, R.W. and ULROTHIRS, W.W.. 1985, Water-mck interac- 

tions in sedimentary basins. In: Relationship of Organic Hotter 

and Mineral Diaqenesir, lecture notes for Short Course No. 11. 

SOC. Econ. Paleon. Mineral., pp. 19-176. 

WPI, C.F., OPALINSKI, P., and Jm, N.P., 1980, Stratigraphy of the 

able Head ~roup. Canadian Journal of ~arth sciences, v. 17, p. 

1007 - 1019. 

nm, H.n., 1975, stratigraphy of the ordovician st. George croup in 

the Port au Choix area, western Newfouodland. Can. Jour. 01 BarLh 

Sciences, Y. 12, p. 589-59L 

KNIGHT, I., 1977, The Cmbrian-Ordovician platfoml mckr of thc 

Northern Peninsula, Neufoundiand. mineral Devel. Division, Neu- 

foundland Dept. of nines and Energy, Reprt 77-6. 

MIGHT, I., 1978, ~latfomal sedbnta on the Great Northern Peninsula: 

stratigraphic studies and gealogicai mapplng of the mcth st.

Barbc distiiet. Minerel Devel. Division, Nowloandland Oept.. or 

,a:! I 

Mines and Energy. Report 78-1, p. 140-150. 

KNIGHT, I., 1980, Ca6ro-Ordov1cian carbonate stcatigiaphy at vcstcrn . 

Nwfoundland; sedimentation, diagenrsis innd rinc-lead ainera1ia;l- 

Lion. Mineral Devel. Division, ~eufoundlund oept. oc Mines and 

Energy, Open Pile Nlld. 1154. 

KNIGHT, I., 1983. Geology of Wro-Ordovician mcks in ports of thc 

Castor River, St. John Island and Port saunders map sheets. 

Mineral Devel. Division, Newfoundland Dept. OF Nines and Bnergy. 

Report 83-1, P. 1-10. 

KNIGHT, I., 1984, Mineralization in Wro-Ordovician rocks. western 

Newfoundland, in SHINDEN H.S.(ed.), Mineral Deposits of 

~ewloundlend: li 1984 Perspective, Newfonndland and Labrador 

oepartmnt of Mines and Energy, Mineral Development Division, 

p.37. 

KNIMT, I., 1985a, Gwlogical mawing of Wrisn and Ordovician 

sedimentary mcks of the Bellburns (12 115.6). Portland Creek I12 

714) and Indian Lookout (12 113) map urea., Great Northern l-nin- 

sula, ~ewfounaland. Mineral Devel. Division. Newfoundland Dcpt. of 

Mines and Energy, Report 85-1, p. 79-88. 

KNIGHT, I., 1985b. Geology or the Bellburns mp sh-t (12 116 end 12 

115). western Newfoundland. Mineral Oevel. Division, Nertovndland 

~ept. of ~ines and energy, Provisional Wep 85-63, scale 1:50,000. 

KNIFRT, I., 1986.. ordwician sedimentary strata of the ~istaiet 8ay and 

"are Bay ena. mineral Devel. Division, Newfoundland Dept. of 

Mines and Energy, Report 86-1, p. 141-160.

KNIGHT, I., lPBbb, Geology of the Port Soundera mtp shml. (12 1/11). 

522 

western Neufousdlsnd. Mineral Ueval. Diviaioli. Nnwfoundlard OeFL. 

of Mines and energy, Mp 86-59, scale 1:5o,WU. 

KNIGHT, I., 1987, Gwlqy of the ~oddickton map area (12 1/16). Mineral 

Deval. Qivision, Newfoundland oept. of nines and Energy. ~upaut 

81-1, P. 343-351. 

MIW, I. and, BOYCE, n.o., 1981, ~eological mapping of the ~ r t 

Saunders (12 1/11). St. John Islcnd (12 1/14) and parts of the 

Torrent RiMr (It 1/10) and Bellburns (12 116) rap sheets, north- 

we~tetn ~ewf~ndlmd. In: Currenl Research. Mineral Dcvel. nivi- 

nion, Navroundland Dept. or Hinca and mcrsy, ~eport 04-1, p. 111- 

124. 

KNIGHT, I. and JRHES, N.P., 1987, The stratigraphy oE the Lower Or- 

hvlcian St. Oeolge Group, western Newfoundland: the interaction 

between eustssy and tectonics. Can. Jour. of earth Sciences, v. 

24. P. 1927-1951. 

KNIGHT, I.; JAKE. N.P. end W, T.E., In press, T& St. George Uncon- 

fomity, Ordovician, Northem Applechlen~: effects of lithl- 

spheric dynamics on the Sauk-Tippecsnoe sequence baundary. 

Bulletin of the Geological Society oE merica. 

KOHOUT, F.A., 1967, Groundwater flow and the geothsmal reqic or tha 

nuridtan plateau. ~slf mart Asseciatlon of C~lla~ical Societies 

Transactions, v. 17, p. 339-354. 

KOHWT, P.A., HENRY, H.R. and BRNKS, J.E., 1971, Hydmqeology related to 

geatheml conditions of the lori id an Plateau, in SMITH, D.L. and 

GRIFFIN, G.H. (eds.) The Gwthenal Nature of the Floridian

Plateau. Special Publication. no. 21. Plar~do Bureitu ol. Ceoloyy. 

p. 1 - 41. 

521 

KONNEPUP-MSEN, J., 1979. Fluid inclusions in quartz fro. dccp-scatcd . 

vranitio intrusions, wuth Norway. Lithas, v. 12, p. 13-21. 

WITLER, C.W., 1987, Sedimentary basin hydrology m d its relation to 

d~lomitization, abstract. SEPM ~nnual idy year metin9 Abstracts, 

p. 44. 

mS. J.R., 1976, Brecoistion, alteration, and mitleralization In the 

Central Tennessee Sin0 district. Econ. Geology, u. 71, p. 892-903. 

KYLE, J.R., 1981. Geology of the Pine mint lend-zinc district. In: 

Holf, K.H., led.) Handbmk of Strata-bound an4 Stratiform Ore 

Deposits, v. 9, p. 643-741. 

KYLE, J.R., 1983, Econmic aspects of subaerial carbonates. In: Scholle, 

P.A.; Bebout. D.F. and bare, C.L. (eds.) Carbonats deporitia!tal 

envirorn8ents. mr. As.00. Petrol. Geology, misa Okla., p. 13-92. 

mm, L.s., 1973, conterpraneaus doloaitizstion of Middle Pleistocene 

reefs by mteoric water. North >mica. Bull. Marine Xience, v. 

23, p. 64-92, 

IRND, L.S., 1980, me isotopic and trace element geochemistry of 

dolmite: the state of art. In: Zanger, 11.8.; Dunham, J.B. and 

Ethington, R.L. (eds.) Concepts and Models of Dolmitieation. Soc. 

econ. Paleo. nineral., Spec. mbl. No. 28, p. 8'1-110. 

WID, L.s., 1983, ~olwitizatioa. mar. Asaoc. Patrol. Geol. Education 

Course Notes, ser. No. 24. 

m, L.s., 1985, $me origin of massive dolmite. Jour. Geological 

Education, v. 33, p. 112-125.

WWD, L.S., 1987, Basinal doldtiration: constraints imposed by 

tormation-water chemistry (abstr.). I": Abstracts vol. IV. SEW 

Annual Hidyear neeting, Austin, Taxas, p. 46. 

LhNO, L.S., 1989, Dolanitization end dolmite recrystallization, Hope 

ate Formation. North Jdca: reassessment of nlixing zone dolo- 

mite, (abatr.). Geologioal Society of mrica Rbsracts with 

Pwrmn, P. R220. 

LAND, L.S.; SUEU, B.R.I. and MORROW. O.W., 1975, Paleohydmlogy of 

ancient dolmiter: gwehmical evidence. mr. Assoc. Rtrol. 

Gwl. Bulletin, v. 59, p. 1602-1625. 

LhNE, T.E., 1984, Preliminary cleasification of carbonate brwcias, 

Newfoundland Zinc Mines, Daniel's Harbour, Newfoundland. In: 

current Research Part I, Ceol. Surv. of Canada, Poper 84-IA, p. 

505-512. 

LAURENCE, R.A., 1944, An early Omvician sinkhore deposlt of volcanic 

ash and fossilifemus aedhnts in East Tennessee. Jour. Geolagy, 

v. 52, p. 235-2119, 

ma, D.L.. 1979, Twrature and salinity of the fluids responsible 

for rniw amurrencea of sphalerite in ths Ozark region of His- 

souri. Emn. Geolagy, v. 14. P. 931-937. 

~ C H D.L., , and ROWIUI. E.L., 1986, Genstic link between Ovachita 

foldbelt tectonisn and the Hississippi valley-type lcad-zinc 

deposits of the marks. Geology, v. 14, p. 931-935. 

LEE, Y.I. and FRIEDWUI, 0.. 1987, Deep-burial dolmitilation in the 

oedovician Ellenburger Gmup Carbonates, western Texas and south- 

510 

wester" Nar Nexfcc. Jwr. of Sed. Petrology. u. $7, No. 3, p. 564-

557. . 

LFXESQUE, R.J., 1917. Stratigraphy and rcdbontoiogy of Middlc Cambrian 

to Lower Ordovician ~hailow water carbonate racks, western 

NevIoundland, unpublished R. SC. thesis, Mwnrirl University or 

Newfoundland, 256p. 

LINDBMM, 5.. 1986, Textural and fluid inclusion evldencc of ore 

dewition in the Pb-zn deposit of Laisvall, Sweden. Kcon. Geol- 

alq. v. 81, P. 46-64. 

L%UN, 8.X.; DAYIES, G.R.; RUUI, J.F.; CEQULSKI, D.E., 1970, Carbonate 

sedbntstion and envimmsntr, Shark Bay, Western mstrelia. 

Mr. as-. Petrol. Geology, Hmir 13. lblsa, Okle., 223p. 

LOW, B.W., et. al., 1970, molution and diagenesia of Quaternary 

carbonate reymenoea, Shark Bey, Australia. her. Assac. Petrol. 

Geology, Hair 22, 358~. 

m, B.W. and senENrLIK, V., 1976, Dynamic mtmrphim; procssses and 

emducts in Devonian carbonate mcks, Canning Basin. Western 

australia. Geal. sac. Australia, Spec. Publ. 6, 138 p. 

W, R.G. and W m R , R.N., 1985. Lineament rt.rdq, Great Northsrn 

Peninsula, Nwfoundland. Imge pmcessing services, Brisbone, 

australla, Unpubl. report. 

LORBNS, R.B., 1981. sr, w, nn co distrihtion cwfficisnts in 

5!b 

calcite as a function of calcite precipitation rate. Gaoehin. Cos- 

rmchin. Rcta, v. 45, p. 553-561. 

LOVERING, T.G. and PATTEN, L.E., 1962, The effect of m, at la temper- 

ature and presnvn an solutions supersaturated with silica in the 

presence of limrstone and dolmitc. Geoshh. Vls#mchim. Rch, v.

14. P. l87;196. 

UIVERINO, P.S., 1969, The o~.igin of hydmthnml and Lou temperalure 

dolaits. &an. Geology, v. 64, p. 741-1511. 

LOVERING, 1.5.; mem. a. end UIVERINO, T.G., 1978, ovc dcposits al 'hc 

Gilmn district, Eagle County. colorado. U.S. 0~01. sum. Pml. 

Paper 101'1, 90p. 

LUCIA, F.J., 1912, Recognition of evaporite-carbonste shoreline cedi-- 

blh 

mentation. In: Rigby. J.K. and Hanblio, W.K. (eds.) Recoqnilion ot 

Ancient Sedimentary Enviromnts, Soc. of econ. Pnlwn. Mineral., 

Spec. Publ. 16, p. 160-191. 

MACHEL, H.G., 1985, Cathodolwinercence in calcite md dolomit~ end Its 

chemical interpretation. Geoscience Csnada, v. 12, p. 119-148. 

MAQIKL, H.O., 1987. 6me sspeetr of diegenetic sulphate-hydmeorbon 

redox-reactions. In: U6rshail. J.D. (ed.) Diegenesis 01 sedimen- 

tary sequencer. Oeol. Soc. of London spec. Publication. 

MACHEL, n.-G., 1981. saddle dolanite as a by-product of chemical 

conpaction and themhmioal sulfate reductitin. Geology, v. 15. 

No. 10, p. 936-910. 

$o.C!m, H . 4 . and MOUNTJOY, E.W., 1986, Chemistry and envimnments of 

dolonritization - e reappreisal. Earth-Sci. Revievs, v. 23, p. 115- 

2a2. 

W~EL, H.-G. and ~ NFJOY, E.H., 1981, ceneral mnstraints on extensive 

perva~ive dalmitization and their application to the Dsvonian 

0arbonatO~ of -Stem Canada. Bull of Can. Petrol. GeolWy, v. 35, 

p. 143-158. 

MATTER, L., 1967, Tidal flat depsita in the Ordovician of western

Maryland. Uour. Qed. Petmlogy, v. 37, p. 601-609. 

WTTES. B.W., and MOUNTJOY, E.w., 1980, Burial dolmitireriola OP LIW 

Upper Devonian Miettc buildup, Jasper ~atlonal l'ark, Alberta. In: 

Zenger, D.H.; hmbam, J.B.. and ~thisgton, B.L. (cdr. 1 ~oncnpls 

and Wels of Dolomitizatioll. Soc. Econ. Paloo. lincral., Spcc. 

Rlbi. No. 28, p. 259-297. 

,,?I 

W W , J.B., 1983, Geochemistry of Sedimentary Ore Oeporits, New York. 

Springer verleg. 305p. 

MOC%IlWE, R.K., 1917, Gmlagic, fluid inclusion and stable isotope 

studies of the Upper Hississippi Vallay zinc-lead dirtrisl, awth- 

western Wisconsin. unpubl. Ph.D. thesis. Pennsylvania state Univ., 

175~. 

HctLIEVUIS, R.K.; WANES, H.L. and WKm, H., 1980. Sphaierita strati- 

graphy of the ilpper Uississippi Valley zinc-lead disttict, south- 

west wiseondn. Emn. Garlogy, v. 15, p. 351-361. 

MCCOWICK, J.E.; EVANS, L.L.; PPILHER, R.I. and RASNICK, P.D., 1911, 

Envimmnt of the zinc deposits al the mscoi-~efferson City 

district, Tennessre. Econ. G~alogy, v. bb, p. 157-762. 

NcNIUGHTMI, X. and SMITH, T.E., 1986, R fluid inclusion Study of 

sphalerite and dolanite frm the Nanisivik lead-zinc depaait. 

~affin island, ~orthwert Territories, Canada. Boon. Oeoiagy. v. 

81, p. 113-720. 

~YERS, W.J. wd IOmAUN, K.C.. 1985. Isotope gsochmistry of regionally 

extensive calcite cmnt zones and marine components in Nirsi- 

~ ~ i ~ limestones, ~ i a n N ~ W Mexico. In: Schneidemnn, N. and Harris, 

P.M. (edr.) carbonate sediments. Sot. Em". Palm. and Mineral.

Spec. ~ubl: 36, p. 223-210. 

WORE, G.W. and SULLIVAN. G.N.. 1911, Speleolaly: 'hpl#yn>a Prcss, 

Weneck, I.J., ISlp. 

MOORE, N.K., 1911, Distribution of the bsnlhie alqal

McArthur G+oup, Northern Territory, ~ustralia. In: Zonyor,U.II.; 

'..?ll 

Dunhm, J.8. and Ethingtan, R.L. (eds.) Concepts and Hodclr of 

Dolmitization. Soc. Econ. paleon. ~~ncral., spec. pub,. NO. 28, - 

I\llre, Okla., p. 51-68. 

IIURWLY, R.C., 1960, me origin or pomaity In carbonate rocks. Jour. 

Sed. Petmlogy, v. 30, p. 1063-1077. 

UURWLY, R.C. and LUCIR, P.J., 1967, Case and contrci and dolomite 

distribution by mck selestivlty. ~eoi. 8oc. mr. Gulletin, v. 

78, p. 21-36. 

MUSSMU, W.J. and READ, J.F., 1986, Sedmsntolagy and devclopcnt oE a 

passive to convergent margin unconfomity: Hiddls Ordovician Knox 

unsonfomity Virginia Appalachians. -01. Soc. mer. Bulletin, v. 

91, p. 292-295. 

MIISIUUI. W.J.; HONTmEZ, I.P. and Rm. J.P., 1988, Ordwician Knax 

paleokarst unconfomity, Appalachiann. In: Jma, N.P. and Chow 

ymette, P.W. (ads.) ~alwkarat, NEW ~ork. springsr verleg, p. 211- 

228. 

NmNNE, G.H., 1984, Trace fossils in Upper Silurian tidal fiats to 

basin slope carbonates of lrctis canah Jour. of Paiwntolagy, v. 

58, p. 398-415. 

NEUDEBIIUBR, 1.. 1373, he diagsnatic problem of chalk - the mls of 

pressure solution and pare fluid. Neves Jahrbuch fur -01. Paleon- 

toi. Dbh. 143, p. 123-2115. 

NOWLPIN, G.S. and BARNES, C.R., 1987, Them1 maturation of Pelwroic 

strata in eastern Canada f m conodont colour alteration indcr 

(car) ash !

5.80 

tion, hotspbt tracks end mineral ad hydrocarbon potc~t~ai. Gcol. 

Surv. Canade nulletin 369. 

ODER, C.R.L. end HOOK, J.W., 1950, zinc deposila in Lhe sovll~eastern 

rtatsa In: Snyder, F.G. led.) Sympoaiun on ntineroi rcsourccs of 

the southeasr.wn United States: Knoxville, Tamessee. Universil.y 

of Tennessee Press, p. 72-87. 

OW, E.L., 1959, Some sonridarations in deternlning the origin oe ores 

of the Niasisrippi Valley-type. Con. Oeolwy, v. 54, p. 769-189. 

OHLE, E.L., 1980, m e considerations in determining the origin of an 

deposits of the Wissinaippi Valley type - Part 11. won. Gml., v. 

75, p. 161-172. 

OHLE, E.L., 1985, Breccias in Hissrsrippi valley-type deposits. Econ. 

Geology, v. 80, p. 1736-1152. 

OWnON), 6. and RYE, R.O., 1919, Isotopes of sulfur and carban. In: 

Bsrnsa, H.L. (ed.) Gwchenistw of Hydrothemi Ore Deposits, New 

Y,rk. John Niley and Sons, p. 509-561. 

OLIVER. 3.. 1986, Fluids upelled tsctonically From omgenic belts: 

Their mle in hydmcarbon migration and other geologic phenmena, 

Geology, v. 14, p. 99-102. 

OLW, R.L., 1984, Gnesis of palmkarst an6 strata-bound zinc-lead 

sulfide deposits in a Pmteraoic dolortone, northern Baffin 

Island, Canada. Econ Gsology, u. 79, p. 1056-1103. 

Pm. D.G. end JONES, B., 1985, Nature and genesis of breccia badies in 

Devonian strata, Peace point area. Wood Buffalo Park, northeast 

Alberta. Bull. can. Petrol. Gwlogy, v. 33, p. 275-294. 

PW, R.K., 1976. A note on the significance of lamination in ;tram-

lites. sedi;nentolqy, v. 23, p. 319-393. 

PnRIZBK, R.R., 1911, Hydrqcologi.: frmwork of folded and Idulted 

carbonates - influencs of stmc(;urc, In: ~aridek. H.H.. White, 

W.8. and Innmir, D., ed., Hydrology and g,:oche",i.try of roldcd 

and faulted carbonate rmks of the Eentral Appalachian type and 

related land use problems, College of earth end Mineral science, 

Pannsylvenia state university, circular 82 

PARIZEK, R.R., 1916, On the nature and significance of fracture traces 

and lineamnta in cubonate and other terranss, in Yevjevich, v., 

ed., Karat Hydmiagy and Water Resources, p. 41 - 108. 

PaTmSUN, R.J., 1912, 1lydrageolagy and oarbanate diegenesis of o 

coastal sabkh~ Jn the Persian Gulf, unpublished Ph. I)., Princeton 

Univurity. N.J., 412~. 

PRTTBRSON, R.J. end KINSHRN, D.J., 1982, Formation of diegenetic 

dolomite in coastal sabLk along Arabian (Persian) Gulf. her. 

Assoc. Petrol. Gwlagy, v. 66, p. 28-43. 

PHILLIPS, N.J., 1972, Hydrsulic fracturing and mineralization. our. 

G-1. Soc. bndon, v. 128, p. 331-359. 

PIERSON, B.J., 1981, The contml aE cathodolumina~cenee in dolomite by 

imn and manganese. Sedhentolagy, v. 28, p. 601-610. 

m'm,R.w., 1971, Pressure corrections for fhid-inclusion hqeniza- 

tlon temperatures bsed on the volumetric properties of the system 

NaC1-H,O. Jour. Research U.S. Geol. Survey, v. 5, p. 603-601. 

mTT, B.R., 1919, Sedlmentolopy, diagenesir and cryptalgal structures, 

the St. George Group (Lower Otdovicien), vestern Newfoundland. 

unpubl. M.SC. thesis, Hemrial University of Newfoundland. 

5.1 1

PRUTT, B.R., 1982,. Limestone response to stress: prcssurr solutm and 

dolomitization - dilcussion and ampler of conpaction in cnr- 

tonate sediments. Jour. of Sed. Petrology, v. 52, p. 323-320. 

PRATT, 8.R. and JRIRS, N.P., 1982. Cryptalgalmtezoan biohems al Early 

Ordovician age in the St. George Group, western Newfoundlalid. 

Sedimantolaly, v. 29, p. 513-569. 

mTT, B.R. end J mS, N.P., 1986, The St. Oaorge Group (La*er Or- 

dovician) of western Nevfoundland: tidal fiat island madel lor 

carbanate sedimentation in shallow ewiric seas. Sadimfintology, 

v. 33, p. 313-311. 

PR6ZBIM)QWSKI. D.H. and tRReSB. R.E., 1987, Experimantal &retching ol 

532 

fluid inclusitrs in calcite - Implications for diagenetic studica. 

Caalagy, v. 15, p. 333-336. 

PRICE, N.J., 1975. Fluids in the crust of the earth, Scientific Pm- 

gress, v. 62, p. 245 

~ U I N ~ N G.n. , a d %enmr, c., 1984, Appalaohien thrusting, iitho- 

spheric fleare, end the Paleozoic stratigraphy'of tha Eartern 

interior of ~orth wrisa. can. Jour. Ear. science, v. 21. p. 913- 

996. 

PADRBAUGH. R.E.; IIEIICWIT. J.S. and BROWN, J.M., 1968, Geol~gY and ore 

deposits of the Gilnan (Red Cliff, Battle Mountain) district, 

eagle county, colorado. In: Ridge, J.D. led.) Ore Oepitr al the 

Unihd states 1933-1961. mr. Inst. Mining. Metal and Petrol. Ln- 

gineers, v. I, p. 641-664. 

RRDKe, B.H., 1978, cartonate sedilaentatian in tidal end epeirie environ- 

rents and dingenetic overprints: the Nimara, Porntion (Upper

mian-her Ordovician), ceutml Australla. unpubl. 1'h.u. 

theais. Troy, N.Y. Rensaelser Polyt.echoic Institute. 25.1~. 

PADKE, 8.U. and IIATTIIS, R.L., 1980, On the formation and occurrence OF 

aeddle dolomite. Jour. of led, Petrolqy, v. 90, p. 11.19-1168. 

RLMSEY. J.G., 1961, Folding and Fracturing of R03s. Mccraw-Hill, N w 

York, 568p. 

WSEY, J.G.. 1980, The crack-rsal mechanism of rock deformation. 

Nsture, V. 284, p. 135-139. 

RLMSEY, J.F. and HUEER, U.I., 1981, The Techniques of Wern Structural 

G!log~ V01. 2: Folds and Fractures. Aoademis Press, New York, 

700p. 

W, J.F.; (i'OTZINGER, J.P.; BOVA, J.A. and KOERSQlNPR, N.F., 1986, 

hJ1 

Models for generation of carbonate cycles. Gwiogy, v. 14, 8. 107- 

110. 

RHODES. D.; LUNTOS, E.A.; LUNTQS, J.A.; WEBB, R.J. and OWBNS, O.C.. 

1984, Pine Paint ore bodies and their reletionship to the strati- 

graphy, structure, dolmitimtion, end karatification of the 

Middle Devonian barrier cwlex. E-n. Geology, v. 79, p. 931- 

1055. 

RIMDSON, C.K. and PINCKNW. D.H., 1984. The shemice1 and thermal 

evolution of the fluids in tho Cave-in-Rock fluorspar district, 

~llinois: linerslogy, paragenesis and fluid inclusions. Econ. 

Geology, v. 79. p. 1833-1856. 

ROBINSON, B.w., 1980, Isotopic evidence on the origin of sulfur in 

Mississippi valley-type deposits, particvlsrly in the British 

1s1ea. in Ridge, J. D., ed.. Proceedings of the 5'" Puadrennial

I A ~ smaiun, O 

9- Bird. utah, p. 481-493. 

bJ4 

ROEDDER, E., 1968e. TMveratnrs, salinity, and origin of the ors-Corming 

fluids at Pine Point, Northwest hrritorios, canado, front fluid 

inclusion studies. Econ. Geology, v. 61, p. 439-150. 

ROEDDER, E.. 1968b, The non-colloidal origin oE "enllofom" toxluras in 

sphalerite ores. &on. Geology, v. 63, p. 451-,171. 

ROEDDER, E., 1977. Fluid inclusion studies of ore deposits in the 

Yibulnm Tesnd, southeast Missouri. won. Geology, v. 72, p. 474- 

419. 

ROEDDER, E., 1980, fluid Inclusions. Reviews in lineralogy, v. 12, 

Washington, 0.C.. Mineral. Sac. limerico. 

ROBDDER, E. and OWORNIK, E.J., 19E8, Sphalerite color banding: lack of 

correlation with imn content, Pine point, Northwest Territories, 

Canada. Pmer. Mineral., v. 53, p. 1523-1529. 

XOBHL, P.O., 1981, Dilation brecciation - a proposed mchanism of 

fracturing, petrolem expulsion, and dolnitirari@n in the ~ontcr- 

ey Formation. California. In: Garrison. R.E.; Douglas, R.G.; 

Pisfi~tto, B.K.; Isaacs, C.M. and Ingle, J.C. (eda.) The Monterey 

Fornation and Related Siliewus Rocks of California. Soc. econ. 

Paleo. Miner. Pacific Section, Synposium. p. 205-315. 

ROSS, R.J. Jr., et. al., 1982, 0 s Ordovician Spten in the United 

States of menca. International Union of Geological Sciences 

Publiratim 12. 73p. 

ROSS, R.J. Jr. and JAWES, N.P.. 1987, Brachiopod bioatreLigraphy of the 

Middle Ordovicisn mv Hsad and Table Head Gmups, western N ~W- 

foundlend. can. Jour. Ear. science, v. 20, p. 70-95.

PIWAN, E.I.., 1986, Catbdolmineaccnt zonation in hydmthrmel dalmitc 

b*!, 

cements: relationnhip to Mississippi Velley-type Pb-zn minc~.aliru- 

tton in southern nishauri and northern ~rksnsas. I": ~nogni, R.U. 

led.) Pmcess Mineralogy VI. The Metallurgical society Lnc. I,trbi., 

P. 69-81. 

RUPPEL, S.C., 1917, The Chicltsmauga limestone - a cmplex mauic of 

svpratidal to slibtidal carhate shelf envimnnents. In: s.C. 

Rupp~l and K.R. Walker (eds.1 The ccoatratigrsphy of the Middle 

Ordovician of the southern Appaischians; USA: A field excursion, 

university of Tennessee, Departrant of Geolagical Sciences studies 

in Geology. No. 71-1, p. 39-48. 

RYE, R.O. and OWm, H., 1914, Sulfur and carbon isotopes end ore 

genesis: s review. Emn. Geology, v. 69, p. 826-842. 

SIUUWIEM. A,. 1982, Correlation of stratabound mineral deposits in the 

Eady CletBC-8 Sante Nett7ll0tsct of NOrth and Central Peru. In: 

lunstutz, G.C., et. sl. (eds.) Ore Genesis. The State of the Art 

lleidelberg Springer Verlag, p. 508-521. 

SANW, W.B., 1967, Madlson lhhstona IMisdasipplanl, Wind River, 

Warhekie, and Owl Creek Mountains, Wyming. me=. Assoc. Pelml. 

Geol. Bulletin. v. 51, p. 529-551. 

msren, D.P., 1976, Sulphur and lead isotopes in gtreh-bound dew- 

sits. In: Wolf, K.H. led.) Handbwk of Strstabund and Stratifom 

Ore Deposits. v. El~evier, Mlsterdm, p. 219-266. 

SRNGSTER, D.F., 1983, nissiseippi Valley-tps deposits: a gsological 

melange. I": ~irysrsanyi, G.; Grant, S.K.,; Pratt. W.P.; mnig, 

J.W. (*as.) pmeadings volume - International Conference un 

,

Misniaaippi Islley-type zinc-lead deposits. uniu. ~lsxo8lri-Rollo 

Press, Rolla, Missouri, p. 7-19. 

SRNGSTER, D.P., 1988, Brsccis-hosted lead-zinc doporitr in carbonate 

rocks. In: Jmr, N.P. end Choquette, P.H., IPalcokarst, New York. 

Springer verlag. 

SANGSTER, D.P., NOW, G.S., BARNES, C.R., HITCH, M.W.. STRONG, D.F. 

and 0AUNDERS. C.N., 1989, Lre Minsisslppi Valley Type (MVT) 

516 

deposits thermal anmlles?, abstract, Rbstracts 28th Intcrnation- 

a1 Geological Congress, Washington, D.C., v.3, p.18. 

SASS, E., and Urn, A,. 1982, Tha origin of platform hlmites: new 

evidence. mer. Jour. Solenee, v. 282, p. 1180-1213. 

SAUNDERS, C.H. and STROVG, D.F., 1986, Aaressmev!t at iead-zinc deposits 

of the western Newfoundland carbonate platform. In: Current 

Research, Part A, Geol. Sum. of CamJa. Paper 8b-lA, p. 229-231. 

SCIIWIGER, W., 1981, The paradox of drowned reefs end carbonate plat- 

forms. G-1. Sac. Amsr. Bulletin, v. 92, p. 191-211. 

~CH~~~BERGER, 1912, ~ eg Interpretation, vol. I. ~rinciplcr, ~ ew ~ork, 

Sehiumbeqer limited, 113~. 

SMNIDT, v. and NacWNALD, D.A., 1919, The role of semndary proaity in 

the course ol sandstone diageoesis. Soc. =on. Palso. Mineral., 

spec. M I. 26, p. 175-207. 

SCHOLLB, P.R. and WEY, R.B., 1985, Burial dlagenesls out o€ sight, 

out O€ mind! 1": Sohneidemnn, N. end Harris. P.M. leds.) Cer- 

honate msnt.. 80s. Econ. Paleo. mineral., Spec. hlbl. 36, p. 

309-334. 

SCHUC~T. C. and DuNBRR, C.O., 1934. Stratigraphy of western Nev-

foundland. mol. Soc. mer.. Memir I. 123p. 

STOTESE. C.R., et. ai., 1979, Paleozoic base maps. Jour. of Gcology, v. 

87, p. 217-268. 

SaK. H.P.; JRHES, N.P. ; CAI0N.T.J. : and SMEUING, J.D., 1983, 

Sedimentologi~al and stmotural walvtion of the Arubian 

continental mrgin in the Nusendm Mountains and Dibba zone, 

United Wab Emirates. Ewl. Soc. mr. Bulletin, v. 94, p. 1381- 

1400. 

sEcan, D.T. JZ., 1965, ~o!s of fluid pressurs in jointing. mar. .lour. 

of Science, Y. 263. p. 633-616. 

SHEBWW, P.N. and SCHIEFeLBEIN, D.R.J., 1984. The trace fossil- 

sinoidep fmm the Upper Ordovician of the eastern Greet Basin: 

deep burrowing in the early Paleozoio. Jour. of Paleontology, v. 

58, p. 440-447. 

'$77 

SHINN, E.A., 1968, Burrowing in rscent lime sadimnts of Florida and tho 

Bahiunan. Jcur. of Paleontology, v. 42, p. 879-894. 

SHINN,E.A., 1986, nodern carbonate tidal flats: their diagnostic 

features. Colorado School of Nines puarterly, v. 81, p. 7-35. 

SHlNN, E.R.; LOW, R.M. and GINSBURG, R.N., 1969, Anatomy of a Rodern 

carbanate tidal flat, nndma Island, Bahamas. Jour. Sad. Petrol- 

ogy, v. 39, p. 1202-1228. 

SHINN, E.A. and ROBBIN, D.N., 1983. HEchanicsl end chenicai compaction 

in fine-grained shallou-vat= Idstones. Jour. of Yed. Petrology, 

v. 53, p. 595-618. 

SIBLEY, D.P., 1982, me origin of comn dolomite fabrics: elver f m 

the ~liocene Jou~. Sed. Petrology, v. 52, p. 1087-1100.

?:I11 

SIBmY, D.P., 19S9, mlanite stoichionetry, (abrtr.). Oeolagicnl SwieLy 

of marica Abstracts with Pmgriuns, p. 8221. 

SIBSON, R.H.; MCMWRE, J. and RRNKTN. R.H.. 1975, Seismic pumping - a 

hydmthsml fluld transport mechanism. Jour. wl. Soe. London, 

Y. 131, p. 653-659. 

SIms, M., 1984, Uolwitiaation by gmundwater - flow systems in 

c~rbnate platforms. T~.anractions of the ~ulf mat Assmiation of 

Oealagical Societies, v. 34, p. 411-420. 

SIPPSL, R.P., and W E R , B.D., 1964, The solution alteration ot 

carbnate mckr; the effects of taparature and pressure. Onxhim. 

st Cormoshh. Acta, v. 28, p. 1.!01-1417. 

sms, 5.5.. 1963, Sequences in the cretonic irtedor of North marice. 

-01. Soc. hmr. Bulletin, v. 74, p. 93-114. 

SPIPAKIS, C.S., 1983, A possible precipitation mechanism for sulfide 

minerals in Kississippi Valley-type lead-zinc d-its. In: G. 

Kirversanyi, et. al. led.) Pmcaedingr volune Int?rnationel 

Conference on Mississippi Valley-type ~ead-Zinc Daposits. Univ. of 

Missouri-Rolla, Rolla Missouri, p. 211-215. 

SPIRFWS, C.S.,and HEYL. A.V., 1968, Preference of Hissirsippi valley- 

type ores for Paleozoic mcks: A consewenee of conditions for 

forming potential sulfur source sediments, labst..), Geological 

wiety of RL1erica Rbstracta with Prwrams, p. 1\33. 

SPIRRI(IS, C.S. and Hm, A.V., 1989, Possible relationships anon9 

VO~C~II~C ash, pre-we diagenetic pyrite, and Hiasissippi valley- 

type dewsits of southeast Missouri. (abrtr.), Geological Society 

of merica Abstracts with Programs, p. A130.

.STRIl', X.A., 1988,'Vpper Canadian to Whitermkian (Ordovician) 

cunodont biostratigraphy of the upper St. George Groap, wusl:ern 

Yrwfoundlsnd, unpublished M.Sc. thesis, netnorial University 01 

Newfoundland. 

STENZEL, S.R. end JAMES. N.P., 1987. Death and destruction oE an aarly 

Paleoeois carbonat* platform, western Nawfoundlasd (abstr.). in: 

Ahtracts Vol. IV, SEm Annual Midyear Meeting, Austin, Tcx.~, p. 

80. 

STENZEL, S.R. and JANES, N.P., 1988, Fovrldering and burial of on anrly 

Paleuroic carbonate platform, western Newfoundland (nbstr.). In: 

Pmgrem with Rbrtracts, Vol. 13. Joint Annual Healing, Gaol. 

ASIOC. Canada, p. Alll. 

STENZEL, S.R., YdlIGHT, I. and JRHES, N.P., 1990, Carbonate platform to 

foreland bssin; revined stratigraphy of the Table 8e.d Gmup 

(Middle Ordovician), western Newfoundland, Canadian Journal ot 

Earth sciences, vol. 27, p. I4 -26. 

STEVENS, R.X.. 1970, Canbro-Ordovician flysch sedimentation and Leo- 

'139 

tonics in nest Newfoundland and their possible bearing on a pmto- 

ntlontic ocean. owl. Aasuc. of Canada, Special Paper 1, p. 165- 

Ill, 

STEVENS, R.K., and JANES, N.P., 1976. Large rponge-like navndr fron the 

mwer Ordovician of western Newfoundland (abstr.). Gsol. Soc. 

Amr. Bbstracts with P ~ o g V. ~ 8, ~ P. , 1122. 

SmUGE, s.3.. 1980, Conodonts of the Tebic Head Formation (Hiddie 

ordwician); western Nevfeundlend. unpublished Ph. D. thesis. 

smriel University of Newfoundland, St. John's. 413~.

'140 

SlOUGP, S.S., 1982,'Praliminary oonadont biustratigraphy vlld cormiatlon 

of bwer and Middle ~rdovician carbanetea of the st. George Gmup, 

weat Northern Peninsula, ~evfoundland. nineral ueuclop. Uivision, 

Newfoundland Dept. of Mines end Energy, Report 02-3, 59p. 

STOUGE, S.S., 1981, Conodonts or the niddle ordovicien Table Head 

Porntion, H86terr Newfoundland. rossils and strata, v. 16, i45p. 

SYERJENSKY, U.A., 1981a, Isotopic alteration oe carbanate host racks es 

a function of water to rock ratio - an exqle from the Upper 

Missi~bippi Valley rinc-lead district. Econ. Gealqy, v. 76, p. 

154-172. 

SvERmNsKY, D.A. 19Slb. The origin of Hissihrippi valley-Lype deposits 

in the viburnum Trend, Southeast nissouri. con. Geology, v. 76. 

p. 1848-1872. 

mRJKNSKK, D.. 1981, Oil field brines as ore-forming solutions. Won. 

cwlqy, u. 79, p. 27-37. 

SVERJENSKY, D.A., 1986. Genesis of !lirsirsippi Valley-type lead-zinc 

deposits. annual Review Earth Planet. Science, v. 14. p. 177-199. 

SWET, W.C.; ETHINOTON, R.L. and W ES, C.R., 1971. North merlcan 

niddle and uppsr ordovician Conodont faunas. ~eol. sac. mr., 

l-ir 127, p. 163-193. 

SWINDBN, 8,s.; LANE, T.E. end THORPE, R.I., 1988. Lwd-isatop w osi- 

tions of galen. in carbonsts-hosted deposits of vestern New 

fwndiand: evidence for diverse lead wrcrr. Can. Jour. Ear. 

Science, v. 25, p. 593-602. 

T A ~ R H.P. , Jr., 1914, Oxygen and hydmgen isotope evidence for lurge- 

scale circulation and intermtion between gmund waters and

irnwus istrmions, vitll particular refereocs to he San .lu.ln 

volcanic field, Colorado. I": nolmann, 8.3.. el. al. (eda.) 

G-hemica1 Transpart end Kincticr. cdrnegir ~nslit. Washi!>gLon, 

D.C., p. 299-324. 

TAWOR, 8.P.. 1911. Water/rock intsractions and t'r origin oE H.0 in 

granitic batholiths. Jour. (ieol. Sea. London, v. 133, p. 171. 

FAYTOR, H.P. dr.. 1919, Oxygen ;r2 hydmgen isotope relationships in 

hydmtheml minerel depasits. In: Barnes, H.L. (ed.) Geochemis:ry 

of Hydrothermal Ore Deposits, New York, John Niiey and Sons, p. 

236-277. 

TAYLOR, H.; m y, N.C.; KBSLER. S.E.; HcCORUICK, J.E.; MSNICK, F.0. 

and HELLON, N.V., 1983. Relationship of zinc mineralization in 

'3.1 1 

East Tennessee to Appalachian omgenic events. In: G. Kirvarsanyi, 

et. al. (eds.) Proceedings, International conference on Hissl- 

rsippi Valley-type lead-zinc Deposits, Rolla, Univ. of lisraurl, 

p. 211-218. 

TAYLOR, I.; KBSLFR, S.E.; CI1)KE. P.L. and WLLY, W.C., 1983, Fluid 

inclusion evidence for fluid miring. Mascot-~effeeson city zinc 

Di6trict. Tennersae. EcOn. Geology, v. 18, p. 1425-1439. 

IrroDS, H.G. and MONSTER, J., 1965, Sulphur isotope geochsmlstry of 

petroleum evaporite and ancient sear. her. Assoc. Patml. Gaol- 

ogy, Mmir 4, p. 361-377. 

THPAILKILL, J., 1968, Chenlcal and hydmlaiic factors in the excavation 

of limestone caves. Geol. Soc. mr. .Ol~iletin, v. 79, p. 19-45. 

TuAol, J., 1987, Mineralized envimmnta, mtallagenesis and the 

Dowers Valley Fault Cawlex, western Whits Bey: A philosophy for

yold exploration in Newloundland. In: Current Researul~, ~ cw 

roundland Dept. of Miner and Knsrgy, Rcport 87-1, p. 129-144. 

WRNER, J.S., 1974, Dubla-diffusive phenormna, nnnvsi ueview ul Blaid 

Uechanics, v. 6, p.37-111. 

'NRNBR, J.S., 1985, nulticmponcnt mnvscUon, Annual Review of Pluld 

Uechanics, v.17, p.11-44. 

TURNER. J.5. and CMPBELL, 1.H.. 1986, Convection end nixing in mogato 

chrunbers. Earth science Reviews, u.23, p.255-352. 

TURNER, J.S. and CHEN, C.F., 1974, ho-di~mnslonai effects in aoublc- 

diffusive convection. Jour. Fluid. Rech., v. 63, p. Yf7-591. 

.,I, ! 

TURNER, R.J.W. and EINAUDI, M.T. (eds.1, 1986, The genesis of stratilorn 

sediment-hosted lead and zlnc dspoaita: conference proceedings. 

stanbt'd University Publications, Geolqieal Sciences. vol. XX. 

VAIL, P.R.; MITHCUM, R.N. Jr. and THOMPSON, S. 111, 1971, Seiamic 

stratigraphy and global changes of sea lsuel. Part 4. ~lobal 

cycles of relative changes of sea leve:. I": C.E. payton (sd.) 

Sel$mic stratigraphy appiisatlons to hydroeariun exploration. 

her. Assoe. Petml. Gaalogy. Hemlr 26, p. 83-91. 

VAN DER PLUm, B.A. and KESLER, S.E., 1989. Relationship betwen Ap- 

palachian omgenic events, RVT mineralization and remagnetization, 

(abstr.), Gaolagieel Soeiety of M rics Rbstracta with Pmgr-. 

P. 1226. 

V6Im. J., 1978, simulation of limrtone diagcnssis - a &i besd on 

atmntiwn depletion: diacusa~ons. Can. Jour. Ear. Science, v. 15, 

p. 1683-1685.

VEIZER, J., 1983,' Chemical diegenesis of carbonates: tllcory and applica- 

tion of trace eimnt teohnlgue. I": Arthur, LA.; Andcrson, 'T.P.; 

et. dl.. (eds.) stable ~rotopcs in sedimenlary ceology. ~ac. con. 

Palwn. Minerai., Short Course No. 10, p. 3-1 - 3-100. 

VEIZER, J. and DWOVIC, R.. 1974, Stmntium as a tool in facios aneiy- 

$is. Jou~. of Sed. Petrology, v. 44, p. 93-115. 

VON DER ma, C.C., 1977, Stratigraphy and formation of Holocene 

dolmitic carbonate deposits of the Caorong area, South Auslraiiu. 

JoUr. of Sed. Petrology, v. 46, p. 952-966. 

YON DER WRCH, C.C. and JONBS, B., 1976, Sphemlar mdern dolomite 

from the wrong area, south Auatralia, Sedimntolagy, v. 23, p. 

581 - 591. 

VOSS, R.L. and WI, R.D., 1986, The application of cathodoluminercencc 

microscopy to the studf of rparry dolomite frm the Viburnum 

Trend, southeastern nlssouri. In: Hausen. D.M. and Kapp, 0. (eds.) 

Mineralogy - Applications to the Minerals Industry. Pmeedings 

Paul F. Kerr n mrial smsiun, New York. AXHE, p. 51-68. 

W m , K.R. and LRPDRTE. I.F.. 1970. Congruent Eossil cmnities From 

Ordovician end Devonian carbonates of New Yod. Jour. Pelcon., v. 

44. P. 

WmSS. H.R., 1919, Limestone response to stress - prcasure solution 

'41 

and doimifiaation - reply. JCL. of sed. Petrology, v. 52, p.318- 

332. 

m. n.c. and wEY. R.B., 1985, Dlomitieation in a nixing zone ol 

near-sea rater cwposition, late Pleistocene, northsastcrn Yucaton 

peninsula. Jour. of Sed. Petrology, v. 55, p. 407-420.

WATSON, I.M., 190, mniel's nerbour, Nfld. Mike WPE l'ropcrty, Asroar- 

ment Work Report. Unpubl. repart, Nevroundlend Zinc Nines. 

~ITE, D.E., 1965. Saline waters of sedimentary rocks. 11,: Yluidr in 

SYbBurfaC~ envitomentb - a SWIU~. her. I\ascc. Pctml. 

Geologists, nemoir I, p. 312-366. 

NHITE, D.E., 1968, Environments of generation of sane base-">eta1 ore 

deposits. Icon. Geology, v. 63, p. 301-335. 

WHITE, D.E.: Ha, J. and WMINO, C.. 1963, Chedcal cmposition oE 

6Ub8urfaFe Waters. U.S. Em1. Survey Pmf. @per 440-F, 67p. 

WHITE, W.B., 1969, C~nceptusl mdelr for csrbonete aquifers. Fround- 

water, v. I, p. 15-21, 

WHITTINCMN, H.B. and KINDLE, C.ll., 1963, Middle Ordovician Table Head 

5'1d 

Porntion, wsatern Newfoundland. Geol. sas. her. Bulletin, v. 71, 

. 745-758. 

WILLIRNS, H., 1978, Tectonic lithofacier rap of the Appalachian omgen. 

newrial Univeysity of Newfoundland, Hap 1. 

WILLIIUIS. H., 1978, Geological development of the northern Appalachians; 

It's bearing an the evolution of the British Islea. In: D.S. Douea 

and B.E. ~ e e e led%.) Crustal evollrtion in northwestern Rritalo 

and adjacent regions. Seal House Press, Liverpool. England, p. 1- 

22. 

WILLIMS, n., 1904. Iliogeoclines and suspect terranes of the Caiedonien- 

Rp~lechlan orogen: tectonic patterns in the North Atlantic 

region. canadian Journal a€ Earth Sciences, v. 21, p. 887 -901. 

wmms, H., and STEVENS, R.K.. 1971, The mcisnt continental mrgirb of 

eastern North America. In: C.A. Burk avd C.L. Drake. The Geolqy

of mntinental'larg.glns. sprlngcr Veriag, NY, NY, p. 7nL-'196. 

WILLNS, $1.; JAMIS, N.P. and STEVENS, R.K., 1986, llunlber A m ALl~hlllo~~ 

and nsarby grottpa belween ~onne my and lartlmd creek. msLcm 

Newfoundland. In: Current Research, part A, oool. si8r.v. or ,:anadit, 

Paper 85-IA, p. 399-406. 

WILLIAMS, S.H.; BWCI. N.D. and JANES, N.P., 1981, Graptoiitca Imn Lhe 

Wer-Nlddle Ordwicisn St. George and Tabic Bead Groups, wastorn 

Newfoundland, and their correlation with trilobite, brachlopod and 

conodont anes. Can. Jaur. Ear. Sciences, v. 24, p. 456-470. 

WILSON, J.L., 1967, mlbonete-evaporite cycles in lover Uupcrar Wmo- 

ticn of Wliiiston basin. Can. Patrol. -01. Uuilotin, v. 15, p. 

230-312. 

WILSON, J.L., 1915, Carbonate Pacler in Geoiugio Hiulnry. springer 

Verlag. New York, 411p. 

W D , J.R. and HEWETT, T.A.. 1982. Fluid convection and omss transfer in 

pomvs sandstones - a theoretical d ei: Geachim. ct Coanochim. 

Acts, V. 46, p. 1107-1113. 

HOOD, J.R. and HEHEW, T.A.. 1984, Reservoir diageneais end sonvectiva 

fluid flou. In: Mcmnaid, D.A. and Surdam, R.C. fedr.) Ciastis 

Diagensais. M r. Assoc. Petrol. Geologists, Henxlir 31, p. 99-110. 

m-, R.E. and ME, B.R., 1981. Piumbotectonies - thc mdel. Tcctona- 

physics, v. 75, P. 135-162. 

IENOER, D.H., 1983, nurial doimitization in the ~ast murro omt ti on 

(~evonien), east-central California and the significance of Lale 

diagenetic doimitization. Geology, v. 11, p. 519-522. 

ZENOER, D.H., 1988, Dolomitieation: a critical view of sane curmnt 

n;.,!,

views - dlsc~ssion. Jmr. of Sed. Pctmloyy, v. 58, p. 1112-lbl. 

,;.I

APPENDIX A 

Oqgen and CamDn loolope DaIa for oolomhes 

!$IyQ@y - k 6% PDB 6'0 SYOW 

Awalhllna 

Dololamlnile Hawk. 1984 -5.77 + .07 

Haywick. 1984 .7.83 + .05 

Hamlck, 1984 .6.54 2.06 

Caron, 1982 -5.9 t24.1 

Catoche DH.1254.378.5 -4.48 + .M 

Fine Dohslone DH-1254-342 4.54 .05 

ROCk~mlriX 66A 

Breccia 626629 

-7.04 + .04 

5.49 + .03 

Sadde Dolomile DH.1927-TH -6.81 + .01 

Table Head 

Saddle Dobmle In DH.56.C 

Rock.malrk Breccia 

-7.00 1.03 

Coane Sparry 626507 -7.70 + .07 

Doh61018 

Catoche Colon, 1982 4.3 r22.30 

Ume~lone Comn, 1982 4.2 r21.4 

Table Head Comn. 1982 .7.8 +22.79 

Llmrlone 

Muelhuna comn. 1982 4.7 t27.9 

LI~SID"~ 

. 

Saddle Dobmle A L7500-5A -10.51 + .M 

Saddle Dolomil8 B L7500.58 .7.63 i .04 

llack Dobmle L7500.28 448 + .07 

Gray Dobmile L760040 .9.01 + .04 

Pseudobreccia L75004A 4.41 + .05 

PsBY~o~~~Ec~~ FIT8 4.15 1 .W 

Saddle Ddomils FllA -10.12 1 .03 

b vein 

Saddle Dobmlle A K106WB -9.38 + .W 

Sadffle Dolomite B K1080"1A J.92 + .07 

Saddle Dobmile A T9180.2A 4.68 1 .02 

Saddle Dobmlle B T9180-1A -8.84 + .06 

Late Caldle L7W05 -11.80 + .07 

Lale Calcile KlOBO-11 -10.19 + .03

APPENDIX C 

X-RAY DIFFRACTION DATA FOR DOLOMITES 

CRYSTAL ESTIMATED 

4rmOLOGY - TYPE , % caC0. 

Coarse Dolastone 

(Aguathuna) 

Fine Dolostone 

(Catoche) 

Rock-matrix 

Breccia 

Medium Crystalline 

Doiostone (Catache) 

Medium Crystalline 

Gray Dolostone 

(Catoche) 

Coarse Crystalline 

Black Dolostone 

(Camhe) 

Saddle Dolomle A 

Saddle Dolomite B 

Coarse Spzrry 

Dolostone

- 

CRYSTAL 

NPE 

Pmm- 14111.) 

APPENDIX D 

SULPHUR ISOTOPE DATA 

SAMPLE 

KGgQj NUMsEnfiQLyJXE 

Early Pyrito voln In Dl1 IVY 1 .+21.3 

Rwh Matrix Breccia 

Earb P Y~I~ T zone PY 2 tn.4 

EW Pyrite K Zone PY3 +23.7 

Galem Lead Lake ~b 1 e2.0 

Galena T Zone Pb 2 t15.0 

Eerhl Red ZnS L~ad Lde ZNl t25.0 

Early Red ZnS F Zone ZN 2 47.4 

Early Brown ZnS T ZOOB ZN 3 e27.6 t28.2 

Ea~k Bmwn ZnS K Zone ZN 4 +27.2 

Eany Yebw zns i zons ZNS +24.9 

Eafb Ydlow ZnS K Zone ZN 6 +21.0 

Brown alter Yellow ZnS K Boa OH ZN 7 t25.9 

Lale Yeflow Bw,i ZnS L Zone ZN 8 +245 

We Yellow BW z n ~ L Zone Z N ~ t22.4 

Lale Yelbw Bmw ZnS L Zone ZN lo +22A 

Late Red ZnS K Zone ZN 12 +205 

~ t Yellow e znS 

~~ 

Table Head 

Malh Breccia 

ZN 13 +21.2 

GYP l + 3.8 

Qyprum L Zone GYP 2 tlD.5 

Barhe L Zone BA 1 t26.2 

CeleQe T Zone CE 1 r28.2 

inl. nnmu MI* .NMn l m.1 I" - Mylyl Y1 Y1 w w roI*m: 

-.nu**. "i.'?!.!E ., ,,m 

"SPO .Unda 

wbra 

'VS w ll C r n 5mm tom. 

kld. 

W'bOt4mI

EWlY Red 61-63.3 37 0.02 1.9-7.0 0.OJ 0.04 

(PbLl

- SImLE - En % 

Yellow-Black 66.8 

yel1.m 

Ye11m-Black 68 

11 3800) 

YellaBlack 70 

yellow 

(T 1100-2) 

Yellou-Blaok 10 

black 

(T1100-2) 

Y~I~OY-BIDF~ 66 

Wlor 

1c-2) 

Yellow-Black 66 

black 

IC2)

Early Yellow ZnS 8-1 0.5 

0.1 

1.0 

fl.!, 

1.0 

1.0 

2.0 

8.0 

1 .o 

1.5 

2.0 

Early Yellm ZnS H-2 0.5 

0.5 

0.5 

2.0 

Barly Yellnr ZnS Lb24O-ZC 1.0 

5.0 

2.0 

Early Yell- 7.- L7500-2h 1.5 

2.0 

Early Yelln ZnS F23 0.5 

0.5 

1.0

Crystal m s mmle NO. t valunx, 

Lats Yellow-Bmvn 19170-U\ 1.0 

zns 

Late Yellow-Bla& 

zns 

lln-3 

2.0 

5.0 

2.0 

5.0 

3.0 

5.0 

5.0 

5.1. 

5.0 

2.0 

1.0 

2.0 

2.0 

2.0 

3.0 

2.0 

2.0 

Late YellorBla& 

2"s 

TI100 1.0 

2.0

Cw~tal m e 

Early UI1site 

mlmite IIII?) 

or 

Late ixlmite 

Smle No. b volume 

1251-401 2.0 

5.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1.0 

1 .U 

1.0 

1.0 

1.0 

1.0 

2.0 

1.0 

2.0 

492-74 1.0 

1.0 

0.5

mstal Rme Sermle No. l Volvne 

Saddle Mhite teR IlMO-2C 0.5 

(nwt to zns) 

Saddle mlmite A L-10 

0.5 

0.5 

0.5 

1.0 

0.5 

0.5 

0.5 

0.5 

1.0 

1.0 

Saddle mhYe A 11500-1 2.0 

2.0 

0.5 

1.0 

Saddle mite A K1060-llc 3.0 

2.0 

2.0 

1.0 

2.0 

1.0 

3.0 

3.0

CNSW Twe g0nrnh Ro. % V O ~ ~ B 

ladab Oowte B 5.0 

(fontinucd) 

sadale m1omi.te A L-lo 

5.0 

2.0 

1.0 

0.5 

2.0 

0.5 

0.5 

0.5 

0.1 

0.5 

Saddle Dolomite A TI100 0.5 

2.0 

L7500-1 1.0 

0.5 

0.5 

0.5 

Late Saddle 

Dolmite P. 

X-1060-llD 0.5 

0.5 

1.0 

1.0 

1.0 

1.0

.9f- 055- 

ao*- 09s- 

09s- oos- 

off- 005- 

001- 

SOP- 095- 

0'01 

0'2 

0'2 

0'2 

O'F 

0'2 

0'2 

O'E 

O'C 

0'2 

0'2 

O'F 

0'1 

0.1 

5'0 

0'1

mt.1 m e '--h 'Pn Ih 

Late calcite K1060-llc 1.0 56' 

Icontinud)

APPENDIX G 

collected and analyzed by Swinden, Thow and Lalie (t988) 

SAMPLE 

LOCATION. FORMATION lFMl 206/204 208/204 

Daniel's Harbour 84-132 17.857 15.475 38.438 

Upper Catoche 

Formation 84-133 18.124 15.471 38.680 

Upper Catoche 

Fornation 84-134 18.116 15.515 38.663 

Upper Catoche 

Formation 84-135 17.983 15.490 30.M17 

Piccadilly-Table Head Fm. 18.204 15.575 38.292 

Frying Pan Pond-Catoche Fm. 17.777 15.482 38.490 

Beaver Brook-Petit Jardin Fm. 17.574 15.425 38.231 

Cook's Harbour.Catoche Fm. 17.772 15.462 38.517 

Hodder-Rattling Bmak Fm. 18.436 15.626 38.266 

St. John lslands-Table Head Fm. 18.506 15.568 39.299 

River of Ponds-Table Head Fm. 19.339 15.613 39.901 

Pikes Feeder Road-Petit Jardin Fm. 17.294 15.388 37.871 

Eddles Cave-Petit Jardtn Fm. 17.431 15.418 37.878 

564

;'RILL HOLE 482, SOUTH OF THE L ZONE, PIG. 1.4 

umer mder / Aguath~na Em. 71 - 83.5 ft. (23.5 - 25.5 an) 

Nladle d e r I 83.5-96 It. (25.5 - 29.5 m) 

her h e r / 9b -270.5 ft. (29.3 - 82.5 ml 

Narkecs - 

Thiok burmwsd intervsl 96 - :31 It. (25.5 - 41.8 m) 

Upper arrlillito 131.5-140 ft. (42 - 42.1 m) 

Urecclas above burrwed beds - 

at 163.5, 171. 181, 188-193, 215.5, 240.5, 252 It. 

DRILL HO~B 490, SOUTH OF THE L ZONE, FIG. 1.4 

Top of the Catech* m. 306 ft. (93.3 m) 

Worms merker 321-323.5 rt. (n.9 - 98.6 m) 

"30" ft. bed belov "u. m" 372-316 ft. (113.4-114.6 m) 

"66" ft, bed belw "u.m." 391-394.5 €t. (119.4-120.1 ml 

and of are, 146 ft. belw "w.n." 460 ft. (140 m)

ThomasEdwardLane.pdf

Create successful ePaper yourself

Delete template?

Save as template?