The Extreme Proterozoic: Geology, Geochemistry, and Climate

The Extreme Proterozoic:Geology,Geochemistry , and Climate......Page 3
Copyright......Page 4
CONTENTS......Page 5
PREFACE......Page 7
Introduction: The Proterozoic......Page 9
REFERENCES......Page 11
1. INTRODUCTION......Page 13
2. 750 MA RECONSTRUCTIONS[STURTIAN GLACIATIONS]......Page 14
4. 600-560 MA RECONSTRUCTIONS[VENDIAN GLACIATIONS]......Page 15
5. TRUE POLAR WANDER......Page 17
REFERENCES......Page 18
1. INTRODUCTION......Page 20
2. GEOLOGICAL SETTING AND AGE......Page 21
3. OVERVIEW OF THE LITHOSTRATIGRAPHY......Page 23
4.2. Analytical Procedure......Page 25
5.1. Geochemical Rock Composition......Page 26
5.2. Weathering and Diagenesis......Page 27
5.3. Geochemical Environment Oxic-Anoxic......Page 31
6. IMPLICATION OF THE DATA......Page 34
7. DISCUSSION......Page 35
REFERENCES......Page 37
1. INTRODUCTION......Page 40
1.1. Seafloor Precipitates and Snowball Earth......Page 41
2. TWO NEW NEOPROTEROZOIC SEAFLOOR FAN OCCURRENCES......Page 42
2.1. Neoproterozoic Glaciation in Death Valley......Page 44
2.2. Neoproterozoic Glaciation in Southeastern Idaho......Page 46
3. SIGNIFICANCE OF THE DEATH VALLEY/SOUTHEASTERN IDAHO SEAFLOOR FANSTO SNOWBALL EARTH......Page 48
REFERENCES......Page 49
1. INTRODUCTION......Page 52
2. MODELS......Page 53
3.2. Carbonate Precipitation......Page 56
3.3. Chemical Weathering and Climate Change......Page 57
3.4. Effects of Carbon Fluxes......Page 58
3.5. Implication for Snowball Earth......Page 59
REFERENCES......Page 60
1. INTRODUCTION......Page 62
2.1. The 'Snowball'......Page 63
3.1. Modern Carbon Cycling......Page 64
3.2. Neoproterozoic Carbon Cycling......Page 66
4.2. Initial Conditions......Page 67
5.1. Atmospheric C02 Response to Sea Level Fall......Page 68
5.2. CO2 Response Limitation by Pelagic Precipitation......Page 70
5.3. The Importance of Feedbacks in the System......Page 71
6.1. The Occurrence of Extreme Ice Ages......Page 73
6.2. The Origin of the 'Cap' Carbonates......Page 74
7. A 'SLUSHBALL EARTH' WITH CAP CARBONATES?......Page 75
REFERENCES......Page 76
1. INTRODUCTION......Page 80
2.2. GCM Simulations of Neoproterozoic Glacial Conditions......Page 81
3. CONCLUSION......Page 84
REFERENCES......Page 85
1. INTRODUCTION......Page 86
2. SHORT REVIEW OF THE PLAUSIBLE TRIGGERS......Page 87
3.2. The Geochemical Model and the Coupling......Page 88
4.1. Overview of the Climatic Simulations......Page 89
4.2. No Relief Versus Pan-African Orogeny Experiments......Page 91
REFERENCES......Page 94
1. INTRODUCTION......Page 97
3. NEOPROTEROZOIC BOUNDARY CONDITIONS AND MODEL DETAILS......Page 100
4. CLIMATE RESULTS FOR 840 PPMV C 0 2......Page 101
5. ICE SHEET RESULTS FOR 840 PPMV C 0 2......Page 103
6. CLIMATE RESULTS FOR 420 PPMV C 0 2......Page 106
7. ICE SHEET RESULTS FOR 420 PPMV C 0 2......Page 107
8. SUMMARY AND DISCUSSION......Page 108
REFERENCES......Page 110
1. INTRODUCTION......Page 112
2.1. The Ice Sheet Coupled Energy Balance Model EBM/ISM......Page 116
2.2. The Community Climate System Model CCSM of the US National Center for Atmospheric Research vl.4......Page 117
3.1. Neoproterozoic Equilibrium Climates from the EBM/ISM and the Possible Existence of a "C02Attractor"......Page 118
3.2. A Simulation of the Climate of the Neoproterozoic Period Using the NCAR CCSM......Page 120
4. A " C 0 2 ATTRACTOR" IN THE NEOPROTEROZOIC......Page 124
REFERENCES......Page 128
INTRODUCTION......Page 130
INTERPRETATION OF SEDIMENTARY STRATA:ALLOSTRATIGRAPHY VERSUS SEQUENCE STRATIGRAPHY......Page 131
DIAMICTITES AND TILLITES: A CASE OF MISTAKEN IDENTITY......Page 132
GLOBAL DISTRIBUTION OF DIAMICTITES REQUIRES GLOBALLY SYNCHRONOUS GLACIATION......Page 139
THE BIOSPHERE SHUTS DOWN IN RESPONSE TO EXTREME GLOBAL COLD AND FROZEN OCEANS......Page 142
CARBON ISOTOPE EXCURSIONS ARE DRIVEN BY GLOBAL GLACIATION......Page 143
DISCUSSION......Page 144
REFERENCES......Page 145
1. INTRODUCTION......Page 151
3. STABLE ISOTOPES IN NEOPROTEROZOIC CARBONATES ASSOCIATED WITH GLACIAL DEPOSITS......Page 152
4. THE SNOWBALL EARTH HYPOTHESIS......Page 153
5. DISTRIBUTION OF EVIDENCE OF PALEOPROTEROZOIC GLACIATIONS......Page 154
6. TECTONIC SETTING OF PALEOPROTEROZOIC ROCKS OF NORTH AMERICA......Page 156
7. PALEOPROTEROZOIC GLACIAL DEPOSITS IN FENNOSCANDIA......Page 157
8. PALEOGEOGRAPHY AND PLATE TECTONIC SETTING OF NORTH AMERICAN AND FENNOSCANDIAN PALEOPROTEROZOICGLACIOGENIC ROCKS......Page 158
10. PALEOPROTEROZOIC GLACIAL DEPOSITS OF SOUTH AFRICA......Page 162
12. SUMMARY AND DISCUSSION......Page 164
13. CONCLUSIONS......Page 166
REFERENCES......Page 167
1. INTRODUCTION......Page 172
3. THE CLIMATIC IMPACT OF HIGH OBLIQUITY......Page 174
4. CONCLUSION......Page 179
REFERENCES......Page 181
1. INTRODUCTION......Page 182
2. THIN ICE CALCULATIONS......Page 183
3. APPLICATION TO SNOWBALL EARTH......Page 184
4. DISCUSSION......Page 186
REFERENCES......Page 187
1. INTRODUCTION......Page 188
2 . NEOPROTEROZOIC GLACIATIONS......Page 189
3. NEOPROTEROZOIC FOSSIL RECORD AND GLACIATIONS......Page 193
4. DISCUSSION AND CONCLUSIONS......Page 197
REFERENCES......Page 198
1. INTRODUCTION......Page 204
3. CONTINENTAL POSITIONS AND GLACIATION......Page 205
4. STROMATOLITES, PHYTOPLANKTON AND BIOSPHERIC CONTROL OF CLIMATE......Page 207
5. TINDIR GROUP MICROFOSSILS:A RELICT ICE MICROBIOTA......Page 209
7. A BIOSPHERE-INDUCED MELTDOWN......Page 211
8. CLIMATE IMPLICATIONS......Page 212
REFERENCES......Page 216