Archean Greenstone Belts (eBook)

Front Cover 1
Archean Greenstone Belts 4
Copyright Page 5
Contents 8
Preface 6
CHAPTER 1. ARCHEAN GRANITE-GREENSTONE TERRANES 10
Introduction 10
General features of Archean granite-greenstone terranes 14
General features of Archean high-grade terranes 16
Archean cratonic basin associations 17
The basement problem 18
Geophysical characteristics 19
Major granite-greenstone provinces 21
CHAPTER 2. GREENSTONE BELT STRATIGRAPHY 51
Introduction 51
Stratigraphic sections 51
Cyclicity 61
Relationships between greenstone belts 63
General stratigraphic features 72
CHAPTER 3. VOLCANIC AND HYPABYSSAL ROCKS 73
Introduction 73
Alteration 75
Ultramafic and mafic igneous rocks 81
Andesites 114
Felsic volcanic and hypabyssal rocks 120
Rocks with alkaline affinities 125
Igneous rock series 129
Stratigraphic variations in composition 131
CHAPTER 4. SEDIMENTARY ROCKS 137
Introduction 137
Clastic sediments 137
Provenance 153
Non-clastic sediments 160
Sedimentary environments 164
The Archean oceans and atmosphere 175
CHAPTER 5. GRANITIC ROCKS 177
Introduction 177
Field associations 180
Pegmatites and related rocks 191
Mineralogy 192
Composition 193
Origin 204
CHAPTER 6. STRUCTURE AND METAMORPHISM 211
Introduction 211
Areal studies 213
Strain estimates in greenstone belts 234
Relationship of low-grade to high-grade terranes 236
Archean geotherms 245
CHAPTER 7. MINERAL DEPOSITS 249
Introduction 249
Massive sulfide deposits 249
Iron formation 258
Manganese formation 259
Gold deposits 260
Chromite deposits 262
Miscellaneous metallic deposits 263
Non-metallic deposits 263
CHAPTER 8. ARCHEAN LIFE 267
Introduction 267
The earliest evidence of life 269
CHAPTER 9. MAGMA ORIGIN AND SOURCE 281
Introduction 281
Magma production 282
Composition and evolution of the Archean mantle 304
CHAPTER 10. ORIGIN AND EVOLUTION OF ARCHEAN GRANITE-GREENSTONE TERRANES 319
Introduction 319
The Archean thermal regime 319
Plate tectonics in the Archean 323
The expanding earth hypothesis 328
Origin of the crust 330
Composition of the primitive crust 334
Growth of the early crust and lithosphere 337
Relationship between high- and low-grade Archean terranes 344
Tectonic models for the origin of Archean granite-greenstone terranes 347
Towards an integrated model 371
References 389
Subject Index 431