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$Fayek & Kyser 2000 uraninite fractionations.pdf - Queen's University$

CHAPTER 2 TECTONIC HISTORY OF THE NORTH AMERICAN SHIELD RECORDED IN URANIUM DEPOSITS IN THE BEAVERLODGE AREA, NORTHERN SASKATCHEWAN, CANADA Abstract Paragenetic and structural relationships and geochronology of minerals in uranium deposits in the Beaverlodge area, Northwestern Saskatchewan, Canada, reveal six periods of uranium mineralization associated with multi-stage deformation during the Proterozoic. The Saint Louis fault and the Main Ore shear zone are northeast striking, southeast-dipping, oblique-normal and dextral fault systems that have mylonite-dominated footwalls. These faults display evidence of exhumation and episodic structural reactivation at progressively shallower crustal levels, accompanied by fluid flow, hydrothermal alteration, and uranium mineralization. New geochronologic data on uranium mineralization and alteration events record over 2.3 Gyrs of protracted tectonic evolution of the North American shield. 207 Pb/ 206 Pb ages of 2293±17 Ma and 2289±20 Ma date two minor uranium mineralization stages associated with cataclasite rocks and early tensional veins, respectively, coincident with late Arrowsmith orogenic exhumation. Following emplacement of the Gunnar granite at 2321±3 Ma, albite metasomatic alteration of the granite is associated with a third moderate uranium mineralizing event. During the late Paleoproterozoic, exhumation along major faults caused the deformation style to change from dominantly brittle-ductile to brittle at shallower structural levels. Massive brecciation of pre-existing rocks is associated with the 19
fourth and most significant uranium-mineralizing event at 1848±5 Ma, coincident with fault reactivation during tectonic shortening and regional metamorphism related to the Trans- Hudson Orogen or more likely post-peak compressional uplift during terminal collision of the Taltson-Thelon Orogen. Subsequently, formation of the Martin Lake Basin and intrusion of mafic dikes are related to the fifth minor uranium mineralizing event at 1812±15 Ma reflecting rifting related to late stage Trans-Hudson Orogen. Late mineralized veins during the Mesoproterozoic crustal growth of the Nuna supercontinent are associated with the sixth mineralizing event at 1620±4 Ma, coincident with the Mazatzal Orogen and the formation of the unconformity-related uranium mineralization in the proximal Athabasca Basin. Post-mineralization alteration and resetting events of uraninite further record various major orogenic events that have affected the North American shield. 2.1. Introduction Deeply exhumed fault zones can serve as vehicles to understand the complex timing relationships between deformational, hydrothermal and ore-forming processes. An important step in understanding the structural setting of uranium deposits associated with highly and multiply deformed and metamorphosed Paleoproterozoic terranes is establishing the timing relationships of fault activity and uranium mineralization to regional thermotectonic events. The Beaverlodge area in the central-southern Archean Rae province, Northwestern Saskatchewan, Canada (Fig. 2.1), hosts numerous fault-controlled uranium deposits. The Main Ore shear zone at the Cinch Lake deposit and the Saint Louis fault at the Ace-Fay- 20
Page 1 and 2: FLUID EVOLUTION AND STRUCTURAL CONT
Page 3 and 4: Abstract Uranium deposits associate
Page 5 and 6: Co-Authorship This thesis and the m
Page 7 and 8: Sarah Rice and Jonathan Cloutier, a
Page 9 and 10: TABLE OF CONTENTS Abstract………
Page 11 and 12: 2.5.2. Temporal relationships of fa
Page 13 and 14: 4.5.3. Isotopic compositions of min
Page 15 and 16: List of Figures Figure 1.1. General
Page 17 and 18: Figure 4.16. Distribution of 207 Pb
Page 19 and 20: Table 4.4. Isotopic data of the U-P
Page 21 and 22: processes by which these deposits f
Page 23 and 24: Figure 1.1. Generalized geological
Page 25 and 26: which is the equivalent of the Mill
Page 27 and 28: dolostone and carbonaceous shale (L
Page 29 and 30: Mineral Field (Figure 1.2). Many de
Page 31 and 32: 2005). U mineralization is controll
Page 33 and 34: Figure 1.4. Schematic representatio
Page 35 and 36: In particular, the key issues to be
Page 37: genetic model for the U mineralizat
Page 41 and 42: The Beaverlodge area is part of the
Page 43 and 44: 1998; Hartlaub and Ashton, 1998). R
Page 45 and 46: (D 1 ) produced a regional migmatit
Page 47 and 48: These previous age models do not ta
Page 49 and 50: the age when the concentrations of
Page 51 and 52: Figure 2.3. A: Detailed geologic ma
Page 53 and 54: hornblende-feldspar gneiss showing
Page 55 and 56: east-west striking en-échelon quar
Page 57 and 58: and broken Kfs 1 and Qtz 1 embedded
Page 59 and 60: A Meters LEGEND B Figure 2.6. A: De
Page 62 and 63: Figure 2.7. Microphotograph of vari
Page 64: eplaces Kfs 1 feldspars (Fig. 2.7A)
Page 67 and 68: the Qtz 1 quartz dissolution result
Page 69 and 70: Figure 2.9. Microphotograph of typi
Page 71 and 72: uraninite (Fig. 2.10). The errors o
Page 73 and 74: Figure 2.10. Backscattered Electron
Page 75 and 76: post-mineralization alteration duri
Page 77 and 78: Post-mineralization alteration even
Page 79 and 80: Volcanic-type ±U 5 (Sample 6139, G
Page 81 and 82: 6134 pt8a 2 Gunnar 82.92 2.92 5.30
Page 83 and 84: Regression to zero content of the s
Page 85 and 86: faults (Fig. 2.13C). The breccias w
Page 87 and 88: Figure 2.13. Schematic cross-sectio
Page 89 and 90:
Mylonites were then reactivated at
Page 91 and 92:
and thrusting during the 1.94-1.92
Page 93 and 94:
Beaverlodge area (Morelli et al., 2
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dikes (Ernst and Buchan, 2001b) and
Page 97 and 98:
Figure 2.15: Distribution of 207 Pb
Page 99 and 100:
CHAPTER 3 GENESIS OF MULTIFARIOUS U
Page 101 and 102:
eccia-type. The other styles of min
Page 103 and 104:
The basement consist of Neoarchean
Page 105 and 106:
of essentially unmetamorphosed arko
Page 107 and 108:
WDX X-ray spectrometers at Carleton
Page 109 and 110:
3.4. Results 3.4.1. Paragenesis of
Page 111 and 112:
are derived from their chlorite cry
Page 113 and 114:
Figure 3.4. Photomicrographs of typ
Page 115 and 116:
3.4J). Py 6 Pyrite and Cpy 5 chalco
Page 117 and 118:
mineralization varies from 25.70 to
Page 119 and 120:
6137APt71 60.67 13.73 4.59 6.48 0.0
Page 121 and 122:
Fig. 3.6A). The Ca may result from
Page 123 and 124:
Sample ID 1 ± 2 ± 3.a ± 4 ± 5.a
Page 125 and 126:
Stable isotopic O and C composition
Page 127 and 128:
Sample ID Deposit Mineral Mineral v
Page 129 and 130:
equilibrium with a fluid having δ
Page 131 and 132:
Syn-ore Chl 8 chlorite sampled from
Page 133 and 134:
Figure 3.9. Binary diagrams showing
Page 135 and 136:
Figure 3.10. Chondrite-normalized R
Page 137 and 138:
Retrograde metamorphism Early vein
Page 139 and 140:
contents in syn-ore Chl 4 chlorite
Page 141 and 142:
decompression and hydration reactio
Page 143 and 144:
mineralizations, which upgraded the
Page 145 and 146:
metamorphic origin of the main U 4
Page 147 and 148:
y the abundance of Ap 1 apatite and
Page 149 and 150:
of late fluid events that have affe
Page 151 and 152:
CHAPTER 4 FLUID EVOLUTION AND GENES
Page 153 and 154:
1990, 1991; Wyborn et al., 1990). H
Page 155 and 156:
stable isotope geochemistry, U-Pb g
Page 157 and 158:
coincident with the initiation of s
Page 159 and 160:
plasma mass spectrometry (LA-HR-ICP
Page 161 and 162:
The Coronation Hill deposit occupie
Page 163 and 164:
arsenides, nickel selenide and copp
Page 165 and 166:
No corrections were made to the 238
Page 167 and 168:
which was interpreted as being asso
Page 169 and 170:
porphyry and coated by Chl 1 formin
Page 171 and 172:
Mineralized breccias showing quartz
Page 173 and 174:
SOUTH ALLIGATOR RIVER GROUP EL SHER
Page 175 and 176:
A Carbonaceous Shale B Src 1 Qtz 1
Page 177 and 178:
A Granite Qtz 0 fragments Qtz 0 B M
Page 179 and 180:
chemical composition as a result of
Page 181 and 182:
Sample I.D SiO 2 CaO FeO ThO 2 MnO
Page 183 and 184:
site occupancy (Cathelineau, 1988).
Page 185 and 186:
Mineral values Temperature Fluid va
Page 187 and 188:
Corrected ratios Apparent ages ( ±
Page 189 and 190:
G H Figure 4.12. U-Pb concordia dia
Page 191 and 192:
Figure 4.13. Pb-Pb isochron diagram
Page 193 and 194:
and 4.12B), and to 207 Pb/ 206 Pb a
Page 195 and 196:
160 o C at Coronation Hill. The tem
Page 197 and 198:
Figure 4.15. Conceptual genetic mod
Page 199 and 200:
of the Koolpin Formation, while dep
Page 201 and 202:
at ca. 1820 Ma, approximately 40 My
Page 203 and 204:
culminating with the formation of R
Page 205 and 206:
deposits is related to fluids deriv
Page 207 and 208:
CHAPTER 5 GENERAL DISCUSSION 5.1. I
Page 209 and 210:
ed-bed strata and associated volcan
Page 211 and 212:
character of the fluid that formed
Page 213 and 214:
5.2.1.2. Metamorphic-related uraniu
Page 215 and 216:
during brecciation or reduction as
Page 217 and 218:
ca. 1820 Ma that triggered reactiva
Page 219 and 220:
Plutons Event at 1.4 Ga (Barinek et
Page 221 and 222:
Kolari-Kittila Province Kuusamo Pro
Page 223 and 224:
The uranium deposits in various pro
Page 225 and 226:
Fig. 5.6. Distribution of the Rorai
Page 227 and 228:
Roraima Basin, similar to what is o
Page 229 and 230:
etween ca. 2.3 Ga and 1.9 Ga. Later
Page 231 and 232:
REFERENCES Adams, J., 1989. Postgla
Page 233 and 234:
Ashton, K.E., 2010. The Gunnar Mine
Page 235 and 236:
Bowles, J.F.W., 1990. Age dating of
Page 237 and 238:
Cuney, M.L., 2005. World-class unco
Page 239 and 240:
deposits in the Athabasca Basin, Sa
Page 241 and 242:
Hartlaub, R.P., Heaman, L.M., Chack
Page 243 and 244:
Saskatchewan Geological Survey, Sas
Page 245 and 246:
Kyser, K., and Cuney, M., 2008. Geo
Page 247 and 248:
two-sided oblique-slip collisional
Page 249 and 250:
Creek Geosyncline: in ‘The minera
Page 251 and 252:
Piper, J.D.A., 2004. Discussion on
Page 253 and 254:
99.Sheppard SMF and Gilg HA 1996. S
Page 255 and 256:
Proceedings Darwin Conference 1984
Page 257 and 258:
Wingate, M.T.D, Pisarevsky SA, Evan
Page 259 and 260:
Sample Deposit 207 Pb/ 206 Pb ±2σ
Page 261 and 262:
Page 263 and 264:
Page 265 and 266:
APPENDIX B REE contents of various
Page 267 and 268:
Sample Y Zr Cs Ba Th La Ce Pr Nd Sm
Page 269 and 270:
Sample ΣREE TLREE THREE LREE/HREE
Page 271 and 272:
SAMPLE ID. SiO 2 TiO 2 AL 2O 3 CR 2
Page 273 and 274:
SAMPLE ID. SiO 2 TiO 2 AL 2O 3 CR 2
Page 275 and 276:
APPENDIX E Electron microprobe data
Page 277 and 278:
SAMPLE Si 4+ AL 4+ Total AL 6+ Ti 4
Page 279 and 280:
SAMPLE Si 4+ AL 4+ Total AL 6+ Ti 4
Page 281 and 282:
Sample ID. Deposit UO 2 SiO 2 CaO F
Page 283 and 284:
Sample ID. Deposit UO 2 SiO 2 CaO F
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Sample ID. Al 2O 3 CaO FeO K2O MgO
Page 291 and 292:
Sample ID. Al 2O 3 CaO FeO K2O MgO
Page 293 and 294:
250 85 330 40 145 70 25 65 30 30 27
Page 295 and 296:
Mineralized veins Quartz veins 276
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