MINERALOGICAL ASSOCIATION OF CANADA

SHORT COURSE HANDBOOK

VOLUME 8, MAY 1982

EDITED BY: P. CERNY

GRANITIC PEGMATITES IN SCIENCE AND INDUSTRY

A short course sponsored by the Mineralogical Association of Canada and held immediately prior to their 1982 Annual Meeting at the University of Manitoba, Winnipeg, Manitoba, May 13th-16th.

Organizing Committee: P. Cerny, R.B. Ferguson, F.C. Hawthorne, A.C. Turnock

I IN UB/TIB Hannover 89 102 948 453 o

NF o • RN 8053(8) Winnipeg May 1982 TABLE OF CONTENTS /I A/ ZC?5~3 (?) INTRODUCTION

ANATOMY AND CLASSIFICATION OF GRANITIC PEGMATITES P. (Wny 1

Introduction 1 Phenomenology and Physiography 1 Geological Classification 1 Age Distribution 2 Geological-Structural Affiliation 5 Regional Distribution 8 Relation to Metamorphic Grade 9 Relation to Granites 11 Regional Zoning of Pegmatite Groups 12 Chemical Composition 15 Mineralogy 19 Shape and Size 20 Internal Structure 22 Classification 28 Internal Structure and Paragenesis 28 Bulk Composition 29 Mode of Formation 30 Petrogenesis and Geochemistry 30 Re f erences 32

MINERALOGY

QUARTZ AND THE FELDSPARS R.F. Martin 41

Introduction 41 Quartz in Pegmatites 41 Which Polymorph Formed? 42 Composition of the Quartz 43 Fluid Inclusion Studies 44 Stable Isotope Studies 45 Feldspars in Pegmatites 46 One or Two Primary Feldspars? 46 Zonation in Concentrations of Incompatible Elements ... 47 Degree of Si-Al Order of Pegmatitic Feldspars 49 The Intergrowth of Quartz and Feldspar 56 References 57

THE MICA GROUP F.C. Hawthorne and P. Cerny 63

Introduction 63 Structure 64 The Ideal Mica 64 Structural Distortions 66 Cation Ordering 68 TABLE OF CONTENTS

Crystal Chemistry 68 Phlogopite-Biotite Series 68 Muscovite-Lepidolite Series 72 Zinnwaldite-Lepidomelane Series 73 Paragenetic Types of Pegmatite Micas 76 Exomorphic Micas 76 Phlogopite at Contacts with Serpentinite 77 Phlogopite at Contacts with Carbonate Rocks 79 Rare-Alkali Biotite 80 Other Exomorphic Micas 81 Internal Mica Types 81 Biotite 81 "Early" Muscovite 82 Lithian Muscovite, Mixed Types, and Lepidolite 84 "Late" Muscovite 87 Sericitic Alteration 89 Zinnwaldite 89 Miscellaneous Sheet Silicates 90 Cookeite and Manandonite 90 Bowleyite, Bityite, Beryllian Margarite 90 References 91

LITHIUM MINERALS IN PEGMATITES D. London and D.M. Burt 99

Introduction 99 Mineralogy of the Common Lithium Minerals 103 Petalite 103 Spodumene 105 Eucryptite 106 Bikitaite 108 Lepidolite and Lithian Muscovite 108 Cookeite 109 Holmquistite 110 Elbaite-Liddicoatite Ill Amblygonite-Montebraslte 113 Lithiophilite-Triphylite 115 Other Minerals 116 Lithium Aluminosilicate Stabilities in Pegmatites 118 References 122

MINERALS OF BERYLLIUM D.M. Burt 135

Introduction 135 Mineralogy of the Common Beryllium Minerals 139 Chrysoberyl 139 Herderite-Hydroxyherderite 139 Hurlbutite 140 TABLE OF CONTENTS

Beryllonite 140 Phenakite 141 Bertrandite 141 Beryl 142 Euclase 143 Helvite-Danalite-Genthelvlte 143 Bavenite 144 Bityite 145 Milarite 145 References 146

MINERALOGY OF RUBIDIUM AND CESIUM P. Cerny 149

Introduction 149 Rubidium 149 Cesium 150 Cestibtantite 150 Cesian Phlogopite-Biotite 150 Pollucite and Cesian Analcime 151 Crystal Chemistry 151 Structure 151 Physical Properties 152 Occurrence 153 Alteration 154 Stability Relations 154 Rhodizite 155 References 156

SELECTED PERALUMINOUS MINERALS P. £erny and F.C. Hawthorne 163

Introduction 163 Gahni te 163 Topaz 164 Aluminium Silicate Polymorphs 167 Garnets 171 Cordierite 175 References 179

MINERALS OF TIN, TITANIUM, NIOBIUM AND TANTALUM IN GRANITIC PEGMATITES E.E. Foord 187

Introduction 187 Minerals Containing Tin 187 Cassiterite 188 Staringite 188

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Thoreaulite 190 Nigerite 192 Tetrawickmanite 192 Varlamoffite 193 Brannockite 193 Eakerite 193 Stokesite 194 Stannite Group 194 Minerals Containing Titanium 195 Rutile, Struverite and Ilmenorutile 199 Brookite 200 Anatase 200 Ilmenite 201 Crichtonite Group 201 Murataite 202 Pseudorutile 202 Titanite 202 Chevkinite-Perrierite 203 Minerals Containing Niobium and Tantalum 204 Columbite-Tantalite Group 205 Ixiolite (Including Pseudo-Ixiolite) 215 Wolframoixiolite 217 Ashani te 217 Tapiolite 218 Wodginite 218 Simpsonite 220 Pyrochlore Group 220 Stibiotantalite Group 221 Rynersoni te 222 Vigezzite 223 Fersmite 224 Cestibtantite 224 Alumotantite 224 Natrotantite 225 Rankamaite 225 Holtite 225 Behierite 226 Olmsteadite 226 References 227

LANTHANIDE, Y, Th, U, Zr AND Hf MINERALS: SELECTED STRUCTURE DESCRIPTIONS ... R.C. Ewing and B.C. Chakoumakos 239

Introduction 239 AX2 Fluorite Structures and Derivatives 245 AB2O6 Nb-Ta-Ti Oxide Structures 249 ABO^ Structure Types 251 Sorosilicate Structure Types 255 Cyclosilicate Structure Types 256 TABLE OF CONTENTS

Inosilicate Structure Types 257 Phyllosilicate Structure Types 258 Tectosilicate Structure Types 259 References 260

PEGMATITE MINERALS OF P (V) AND B (III) P.B. Moore 267

Introduction 267 The Primary Phosphates 269 Glaserite-Derived Structures 276 Olivine-Derived Structures 277 Other Structures 277 The Metasomatic Products and Hydrothermal Phases 278 The Secondary Phosphates 283 Octahedral Cluster Structures and Structures with

[M27(P0it)2] Clusters 284 The lk Octahedral Corner-Sharing Chain Structures 284 Reduced Phases, Sheet-Like Structures 285 Cis-trans Chain Structures, Edge-Chain Structures 285 The 5A Fiber-Axis Structures 286 The Sheet Structures 286 The Pegmatite Minerals of B (III) 287 References 289

PETROLOGY AND GEOCHEMISTRY

INTERNAL EVOLUTION OF GRANITIC PEGMATITES R.H. Jahns 293

Introduction 293 Internal Features 295 Classification 295 Pattern of Segregation 297 Sequence of Segregation 299 Replacement Features 303 Aplite Units 303 Pockets and Cavities 305 Internal Evolution 308 Challenges for a Genetic Model 308 P-T-X Conditions 310 Viscosity, Diffusion and Convection 312 Processes and Products 314 References 318

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SUBSOLIDUS EQUILIBRIA D.M. Burt and D. London 329

Introduction 329 Treatment of Volatiles 329 Lithium Minerals 332 Beryllium Minerals 336 Nb-Ta-Sn-Ti Oxides 339 Rare Earth Minerals 340 References 344

RUBIDIUM-STRONTIUM ISOTOPE SYSTEMATICS OF COMPLEX GRANITIC PEGMATITES G.S. Clark 347

Introduction 347 The Rb-Sr Method of Age Determination 348 The Influence of Diffusion on Rb-Sr Geochronology 349 Rb-Sr Isotope Studies of Pegmatites in the Middletown Area, Connecticut 350 Hale Pegmatite 356 White Rocks II Pegmatite 358 Rb-Sr Results from the Harding Pegmatite, New Mexico 359 Discussion of Harding Pegmatite Results 361 Black Hills, South Dakota 364 Rubidium-Strontium Pegmatite Results 365 The Winnipeg River District, Manitoba 366 Conclusions 367 References 369

STABLE ISOTOPES IN THE STUDY OF GRANITIC PEGMATITES AND RELATED ROCKS F.J. Longstaffe 373

Introduction 373 Terminology 374 Oxygen Reservoirs 374 Water 376 Sediments and Sedimentary Rocks 376 The Mantle and Derivative Rock Types 377 Oxygen-isotope Geochemistry of Granitoid Rocks 379 Normal - 180 Granitic Rocks 379 Low-180 Granitic Rocks and Meteoric Water-Rock Inter- action 380 High-180 Granitic Rocks and the Role of Sediments 383 Isotopic Exchange between Granites and their Country Rocks at High Temperatures 383 Whole-Rock 618O values in Granitic Pegmatites - "Open- System" Behaviour 385 The Nature of Fluids in Pegmatites 390 TABLE OF CONTENTS

Stable Isotope Variations in Pegmatite Minerals 391 Oxygen-Isotope Equilibrium and Geothermometry 391 Stable Isotope Variations in Granitic Pegmatite-Aplite Dikes, California - a Case Study 397 Concluding Remarks 399 References 400

PETROGENESIS OF GRANITIC PEGMATITES P . ferny 405

Introduction 405 The Parent Medium 406 Aqueous Solutions 406 Volatile-Rich Melts 407 The Pegmatite-Generating Process 408 Pegmatites of the Maximal Depth Formation 409 Mica-Bearing Pegmatites of Deep Levels 410 The Tchupa-Loukhi Pegmatite Field 411 Rare-Element Pegmatites of Intermediate Levels 413 The Winnipeg River Pegmatite District 414 The Southern Black Hills Pegmatite Field 418 The Quartz Creek Pegmatite District, Colorado 422 The Pegmatite Field of Northern Oberpfalz, Bavaria.. 423 Rare-element Pegmatite Belt of the Mongolian Altai.. 426 An Sn, Ta, Li-bearing Pegmatite Field of Central Asia 429 The South Platte Pegmatite District, Colorado 430 Miarolitic Pegmatites of Shallow Levels 432 The Miarolitic Pegmatite Field of the Korosten Granitic Complex 433 General Characteristics of Pegmatite-Generating Granites 435 Concluding Remarks 440 Derivation and Evolution of Calc-Alkalic Granites Generating Rare-Element Pegmatites 442 Sources and Derivation of the "Fertile" Granites 443 Internal Evolution of "Fertile" Granites 444 Separation and Emplacement of the Pegmatites 446 Metamorphic Control of Pegmatite Formations 447 References 450

EXPLORATION AND PROCESSING

EXPLORATION FOR RARE-ELEMENT GRANITIC PEGMATITES D.L. Trueman and P. Cerny 463

Introduction 463

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Regional Programs 464 Geochemical Approaches 464 Search for Parental Granites 465 Geological and Structural Attributes 465 Compositional and Textural Attributes 467 Geochemical Attributes 468 Regional Zoning of Pegmatite Districts 470 Textural and Paragenetic Features 470 Mineral Typomorphism 472 Geochemical Indicators 475 Follow-Up on Reduced Target Area 476 Preliminary Assessment of Pegmatite Potential 477 Mineral Typomorphism 477 Geochemical Indicators 477 Geochemical Search for Hidden Deposits 485 Geophysical Contouring of Hidden Deposits 490 References 491

ORE PROCESSING AT TANTALUM MINING CORPORATION R.O. Burt, J. Flemming and D.L. Trueman 495

Introduction 495 The Tanco Pegmatite ^96 Mineralogy 496 Mineralogical Aspects of Mineral Processing 496 Mining 498 Mineral Processing of Tantalum Ore 498 Metallurgical Control 502 Concluding Comments 503 References 503

FOOTE MINERAL COMPANY - KINGS MOUNTAIN OPERATION I. Kunasz 505

Introduction 505 Mineralogy 506 Geological Setting 507 Mine 507 Beneficiation 508 Mineral Production 508 Potential Products 510 References 511

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THE GREENBUSHES PEGMATITE, SOUTH-WEST WESTERN AUSTRALIA M.I. Hatcher and B.C. Bolitho 513 Introduction 513 History 513 Geology 514 Regional Geology 514 Bedrock Pegmatite Geology 515 Pegmatite Mineralogy 517 Current Mining Operations 518 Mineral Processing 518 Primary Separation 518 Secondary Separation 520 Extractive Metallurgy 521 Hydrometallurgy 521 Pyrometallurgy 522 Analytical Facilities 524 References 525

APPENDIX: FIELD TRIP BACKGROUNDER

THE TANCO PEGMATITE AT BERNIC LAKE, SOUTHEASTERN MANITOBA P. Cerny 527 Introduction 527 Location and General Geology 527 The Pegmatite 529 Internal Structure 529 Mineralogy 532 Geochemistry 538 Petrology 540 Economic Aspects 540 Concluding Notes 540 References 541

THE OSIS LAKE PEGMATITIC GRANITE, WINNIPEG RIVER DISTRICT, SOUTHEASTERN MANITOBA P. Cerny and W.C. Brisbin 545

Introduction 545 Location and General Geology 545 Mode of Emplacement 546 Petrography 549 Mineralogy of the Pegmatitic Granite 549 Petrochemistry 550 Regional Fractionation Trends 552 Genetic Considerations 553 References 554

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