The Precambrian Earth (eBook)

Front Cover 1
The Precambrian Earth: Tempos and Events 4
Copyright Page 5
Contents 12
Contributing authors 6
Preface 18
CHAPTER 1. THE EARLY EARTH 26
1.1. Introduction 26
1.2. Earth's Formation and First Billion Years 28
1.3. The Early Precambrian Stratigraphic Record of Large Extraterrestrial Impacts 52
1.4. Strategies for Finding the Record of Early Precambrian Impact Events 70
1.5. Commentary 87
CHAPTER 2. GENERATION OF CONTINENTAL CRUST 90
2.1. Introduction 90
2.2. Isua Enigmas: Illusive Tectonic, Sedimentary, Volcanic and Organic Features of the > 3.7 Ga Isua Greenstone Belt, Southwest Greenland
2.3. Geochemical Diversity in Volcanic Rocks of the > 3.7 Ga Isua Greenstone Belt, Southern West Greenland: Implications for Mantle Composition and Geodynamic Processes
2.4. Abitibi Greenstone Belt Plate Tectonics: The Diachrononous History of Arc Development, Accretion and Collision 113
2.5. Granite Formation and Emplacement as Indicators of Archaean Tectonic Processes 128
2.6. Diapiric Processes in the Formation of Archaean Continental Crust, East Pilbara Granite–Greenstone Terrane, Australia 143
2.7. Early Archaean Crustal Collapse Structures and Sedimentary Basin Dynamics 164
2.8. Crustal Growth Rates 180
2.9. Commentary 183
CHAPTER 3. TECTONISM AND MANTLE PLUMES THROUGH TIME 186
3.1. Introduction 186
3.2. Precambrian Superplume Events 188
3.3. Large Igneous Province Record through Time 198
3.4. Episodic Crustal Growth During Catastrophic Global-Scale Mantle Overturn Events 205
3.5. An Unusual Palaeoproterozoic Magmatic Event, the Ultrapotassic Christopher Island Formation, Baker Lake Group, Nunavut, Canada: Archaean Mantle Metasomatism and Palaeoproterozoic Mantle Reactivation 208
3.6. A Commentary on Precambrian Plate Tectonics 226
3.7. Precambrian Ophiolites 238
3.8. The Limpopo Belt of Southern Africa: A Neoarchaean to Palaeoproterozoic Orogen 242
3.9. Geodynamic Crustal Evolution and Long-Lived Supercontinents During the Palaeoproterozoic: Evidence from Granulite–Gneiss Belts, Collisional and Accretionary Orogens 248
3.10. Formation of a Late Mesoproterozoic Supercontinent: The South Africa–East Antarctica Connection 265
3.11. A Mechanism for Explaining Rapid Continental Motion in the Late Neoproterozoic 280
3.12. Commentary 292
CHAPTER 4. PRECAMBRIAN VOLCANISM: AN INDEPENDENT VARIABLE THROUGH TIME 296
4.1. Introduction 296
4.2. Terminology of Volcaniclastic and Volcanic Rocks 298
4.3. Komatiites: Volcanology, Geochemistry and Textures 302
4.4. Archaean and Proterozoic Greenstone Belts: Setting and Evolution 336
4.5. Explosive Subaqueous Volcanism 359
4.6. Archaean Calderas 370
4.7. Commentary 381
CHAPTER 5. THE EVOLUTION OF THE PRECAMBRIAN ATMOSPHERE: CARBON ISOTOPIC EVIDENCE FROM THE AUSTRALIAN CONTINENT 384
5.1. Introduction 384
5.2. Archaean Atmosphere, Hydrosphere and Biosphere 386
5.3. Evolution of the Precambrian Atmosphere: Carbon Isotopic Evidence from the Australian Continent 413
5.4. Precambrian Iron-Formation 428
5.5. The Precambrian Sulphur Isotope Record of Evolving Atmospheric Oxygen 446
5.6. Earth's Two Great Precambrian Glaciations: Aftermath of the "Snowball Earth" Hypothesis 465
5.7. The Paradox of Proterozoic Glaciomarine Deposition, Open Seas and Strong Seasonality Near the Palaeo-Equator: Global Implications 473
5.8. Neoproterozoic Sedimentation Rates and Timing of Glaciations—A Southern African Perspective 484
5.9. Earth's Precambrian Rotation and the Evolving Lunar Orbit: Implications of Tidal Rhythmite Data for Palaeogeophysics 498
5.10. Ancient Climatic and Tectonic Settings Inferred from Palaeosols Developed on Igneous Rocks 507
5.11. Aggressive Archaean Weathering 519
5.12. Commentary 530
CHAPTER 6. EVOLUTION OF LIFE AND PRECAMBRIAN BIO-GEOLOGY 538
6.1. Introduction 538
6.2. Earth's Earliest Biosphere: Status of the Hunt 541
6.3. Evolving Life and Its Effect on Precambrian Sedimentation 564
6.4. Microbial Origin of Precambrian Carbonates: Lessons from Modern Analogues 570
6.5. Precambrian Stromatolites: Problems in Definition, Classification, Morphology and Stratigraphy 589
6.6. Precambrian Geology and Exobiology 600
6.7. Commentary 612
CHAPTER 7. SEDIMENTATION THROUGH TIME 618
7.1. Introduction 618
7.2. Sedimentary Structures: An Essential Key for Interpreting the Precambrian Rock Record 627
7.3. Archaean Sedimentary Sequences 638
7.4. Discussion of Selected Techniques and Problems in the Field Mapping and Interpretation of Archaean Clastic Metasedimentary Rocks of the Superior Province, Canada 650
7.5. Precambrian Tidalites: Recognition and Significance 656
7.6. Sedimentary Dynamics of Precambrian Aeolianites 667
7.7. Early Precambrian Epeiric Seas 682
7.8. Precambrian Rivers 685
7.9. Microbial Mats in the Siliciclastic Rock Record: A Summary of Diagnostic Features 688
7.10. Microbial Mat Features in Sandstones Illustrated 698
7.11. Sedimentation Rates 700
7.12. Commentary 702
CHAPTER 8. SEQUENCE STRATIGRAPHY AND THE PRECAMBRIAN 706
8.1. Introduction 706
8.2. Concepts of Sequence Stratigraphy 710
8.3. Development and Sequences of the Athabasca Basin, Early Proterozoic, Saskatchewan and Alberta, Canada 730
8.4. Third-Order Sequence Stratigraphy in the Palaeoproterozoic Daspoort Formation (Pretoria Group, Transvaal Supergroup), Kaapvaal Craton 749
8.5. Commentary 760
CHAPTER 9. TOWARDS A SYNTHESIS 764
9.1. Evolution of the Solar System and the Early Earth 764
9.2. Generation of Continental Crust 768
9.3. Tectonism and Mantle Plumes through Time 772
9.4. Precambrian Volcanism, an Independent Variable 774
9.5. Evolution of the Hydrosphere and Atmosphere 776
9.6. Evolution of Precambrian Life and Bio-Geology 780
9.7. Sedimentation Regimes through Time 783
9.8. Sequence Stratigraphy through Time 786
9.9. Tempos and Events in Precambrian Time 787
References 796
Subject Index 948