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-4O- A ULASSiIUAflCbi 0 GRAiCLI'IU aQUKS iJITh Rthu Pu GIANTS RAP.G JIATHOLITFI, N.iRThiRi L'LIJ'1'A5UTA S. i'iinnsota Goniogical thrvey, University : rliniiu rmth 24inneapolis, Minnesota 55455 A B S T it A U P Figure 1 shows a clnsification or granitic and relate6 roc Vavo'ired by many field geologists. The inadequacy of this scherac and some of its flaws became apparent while investigating granitic rocks from the western part of the Giants -Range tatholith (Algn:nj in Northern iinnesota. For example, rocks which plotted in Uc acianollitc: field were found to lack the characteristics of ar udarncllite: their plagioclases+ were aibite rathor than olioclae, and their muscovite conthnt was as high as 10 percent iiistrd of Lei.nj insignificant. A revised classification proposed in this paper, :il'own in Figaro 2, differs substantiaaly iron the other erie, zln(i. mainly as follows: (1) The edamelllte field is compressed, and the upper limit of its quartz content fixed at 30 percent as against 50 percent. This chane is made lecause adamellites that plot below the 10 percent quartz level (Group 1 adamollites) arid those that plot above the 30 percent quartz level (Group 2 a1ameilites) show the followinj important petrographic differences: (a) muscovite is rare in Group 1 adamel.lites but rniy be present in amounts as hih as 10 percent in Group 2 adamellites, (b) plagioclase in Group 1 ãdaraellites gonorally is more caicic than that in Group 2 adameilites, aid (c) non—opaque dalcic trace minerals (sphene, enidote, apatite) in Group 1 adat;iellites total more than 1 percent, whereas Group 2 adarnellitos generally have a substantially lo'er content of those trace minerals. (2) The granite Itoh is extended not only laterally to incJ1xie the Group 2 ádarnellites, tat also vertically upto the 61) ercent quartz level.
—41- (3) The upper liimit of 30 percent quartz fixed for the adFwellite field is extended towards the Flagioclase-Quartz jnin and the Alkali feldspar—unrtz join; thereby, the granodiorite, tonalito and l'ranite fields of the classification shown in Figure 1 have teen sub—divided into the granodiorite (c30 percent quartz)—quartz granodiorite S>'30 percent quartz), tonalite (30 percent quartz) and the syehogranite c30 percent. quartz)—.rarito (>30 percent quartz) fields. Although one cannot assert that feldenar types rt:vc'nl the tectn:ic ,;rouping of c'r&tites, a correlatioji betweezi the two scouts to oxist. In the noenc1ature of granites, therefore, it is desiratl to izLlicvte the Yeldspar tyne as well as colour, text,'ire, alteration, a;.d Qccassory ainrals. One could thus have niodified root ncuavz like "nicroclinc— calcic oligoclasegranit&', "microcline—albite—granite", "orthocla;..e— ml crocline—calc ic olloc1ase—gran ite", etc. In general terms, these three inodif led root names are correlatable with synkineinatic, kineina tic, and pos t-.kiueina tic grani tes, respectively. late— An application of the revised classification combined wit!' 'idd osorvations has enabled no to recognize twelve distinctiv major rock. units in the western part ot' the Giants Rane batholith where only t.wo principal units were distinguished previously. Its applicability to adjacent areas of the lake Superior region, and elsewhere, needs to Le tested.
Page 1 and 2: -ç — — I: .t. F Geology Superi
Page 3 and 4: TABLE OF CONTENTS INSTITUTE DIRECTO
Page 5 and 6: -2- "P R 0 G R A M" Tate day, Ma9 5
Page 7 and 8: -4- SESSTOM 2 1.00 Business Meeting
Page 9 and 10: -6- F'viday, May Slit, 1970 Page No
Page 11 and 12: -8- SYNTHESIS OF EARLY PRECAMBRIAN
Page 13 and 14: -10- THE SOUTHERN ASSOCIATED PART O
Page 15 and 16: -12- THE STRUCTURE OF THE NORTHERN
Page 17 and 18: -14- MT. ST. JOSEPH - AN ARC}IAEAN
Page 19 and 20: -16- A MODEL FOR TECTONIC VARIATION
Page 21 and 22: -18- EARLY PRECAMBRIAN GEOLOGY OF T
Page 23 and 24: DEFORMATION OF THE SEINE CONGLOMERA
Page 25 and 26: -22- MINERAL POTENTIAL IN CREENSTON
Page 27 and 28: -25-- ROOT SEVERANCE AND TECTONIC T
Page 29 and 30: -27- STRUCTURE OF ThE DULUTH GABBRO
Page 31 and 32: -29- 1. Department of Geology and G
Page 33 and 34: -31-. KEWEENANWAN COPPER DEPOSITS I
Page 35 and 36: —33- The youngest rocks in the ar
Page 37 and 38: -35- STRUCTURAL AN!) METAMORPHIC HI
Page 39 and 40: -37.- ARCHAEAN VOLCANIC STRATIGRAPH
Page 41: ______ __________ _____ IDEALIZED S
Page 45 and 46: -43- Fjgire 2 The revised classific
Page 47 and 48: —45— EVIDENCE FOR A TROPICAL CL
Page 49 and 50: —47-- WIDESPREAD OCCURRENCE OF AL
Page 51 and 52: —49— PROTEROZOIC ROCKS IN THE T
Page 53 and 54: —51— Guide to the Proterozoic R
Page 55 and 56: WEST EAST f * . . .. . . S S S S 5S
Page 57 and 58: ________ — ;—=- — —-- —
Page 59 and 60: —53— The uppermost submember of
Page 61 and 62: —55— Morey notes that sediment
Page 63 and 64: —57— (c) layered mafic bodies,
Page 65 and 66: —59— DESCRIPTION OF STOPS Milea
Page 67 and 68: —6 P- Note downwarping of beds on
Page 69 and 70: —63— Note the lenticular chert
Page 71 and 72: —65— 0.0 From the intersection
Page 73 and 74: —67— STOP 16 In the roadcut to
Page 75 and 76: —69— ThE BEARDMORE-GERALDTON BE
Page 77 and 78: —72— the Quetico belt by Stockw
Page 79 and 80: —72 B— ABITIBI BELT —ø.jsour
Page 81 and 82: —74— Most of the metavolcanic
Page 83 and 84: —76— SELECTED REFERENCES Anonym
Page 85 and 86: —78— Stockwell, C. II., 1964; F
Page 87 and 88: —80— ae DESCRIPTION OF STOPS 0.
Page 89 and 90: —82— STOP 8 (Paint Lake Fault).
Page 91 and 92: -84— Outcrops near the road are o
Page 93 and 94:
—87— Guide to the Port Coldwell
Page 95 and 96:
AGE RELATIONSHIPS The volcanosedime
Page 97 and 98:
.• ____________________ . — .._
Page 99 and 100:
-I- + -4.- -I- - - - - — - 4- ; E
Page 101 and 102:
—93— (3) 'flow—layering' exhi
Page 103 and 104:
GOSSAN ZONE IN SULPHIDE BEARING GAB
Page 105 and 106:
—95— (3) feldspars variably fol
Page 107 and 108:
—97— Fig. 6c Fig. 6b ;' TRAIL T
Page 109 and 110:
Pig. 7 West contact of CROSS SECTIO
Page 111:
PRINCE AR THUR HOTEL ® 0 ® SHOREL
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Program, Abstracts, and Guidebooks - University of Minnesota Duluth

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