1. Theoretical and Experimental Principles ...................... 1
1.1. General Characteristics of Isotopes ........................ 1
1.2. Isotope Effects ............................................ 3
1.3. Isotope Fractionation Processes ............................ 5
1.3.1. Isotope Exchange .................................... 5
1.3.1.1. Fractionation Factor (a) ................... 7
1.3.1.2. The Delta Value (b) ........................ 8
1.3.1.3. Evaporation-Condensation Processes ......... 9
1.3.2. Kinetic Effects .................................... 10
1.3.3. Diffusion .......................................... 11
1.3.4. Other Factors Influencing Isotopic
Fractionations ..................................... 13
1.3.4.1. Pressure .................................. 13
1.3.4.2. Chemical Composition ...................... 14
1.3.4.3. Crystal Structure ......................... 14
1.3.4.4. Mass-Independent Isotope Effects .......... 15
1.3.5. Isotope Geothermometers ............................ 16
1.3.5.1. Theoretical Calculations .................. 17
1.3.5.2. Experimental Calibrations ................. 18
1.4. Basic Principles of Mass Spectrometry ..................... 21
1.4.1. Continuous Flow - Isotope Ratio Mass
Spectrometers ...................................... 23
1.5. Standards ................................................. 23
1.6. General Remarks on Sample Preparation Methods for Gases ... 26
1.7. New Microanalytical Techniques ............................ 27
1.7.1. Laser Microprobe ................................... 27
1.7.2. Continuous Flow Isotope Ratio Mass Spectrometry
(IRMS) ............................................. 28
1.7.3. Secondary Ion Mass Spectrometry (SIMS) ............. 28
1.8. Stable Isotope Variations of Heavier Elements ............. 29
2. Isotope Fractionation Mechanisms of Selected Elements ....... 31
2.1. Hydrogen .................................................. 32
2.1.1. Preparation Techniques and Mass Spectrometric
Measurements ....................................... 33
2.1.2. Standards .......................................... 34
2.1.3. Fractionation Mechanisms ........................... 34
2.1.3.1. Equilibrium Exchange Reactions ............ 36
2.1.3.2. Kinetic Isotope Effects ................... 38
2.1.3.3. Other Fractionation Effects ............... 38
2.2. Lithium ................................................... 39
2.3. Boron ..................................................... 41
2.4. Carbon .................................................... 44
2.4.1. Preparation Techniques ............................. 44
2.4.2. Standards .......................................... 45
2.4.3. Fractionation Mechanisms ........................... 45
2.4.3.1. Inorganic Carbonate System ................ 45
2.4.3.2. Carbon Isotope Fractionations During
Photosynthesis ............................ 46
2.4.4. Interactions Between the Carbonate-Carbon
Reservoir and Organic Carbon Reservoir ............. 48
2.5. Nitrogen .................................................. 49
2.6. Oxygen .................................................... 52
2.6.1. Preparation Techniques ............................. 53
2.6.2. Standards .......................................... 55
2.6.3. Fractionation Mechanisms ........................... 55
2.6.4. Fluid-Rock Interactions ............................ 60
2.7. Magnesium ................................................. 62
2.8. Silicon ................................................... 63
2.9. Sulfur .................................................... 63
2.9.1. Preparation Techniques ............................. 64
2.9.2. Fractionation Mechanisms ........................... 65
2.9.2.1. Dissimilatory Sulfate Reduction ........... 65
2.9.2.2. Thermochemical Reduction of Sulfate ....... 67
2.9.2.3. Isotope Exchange Reactions ................ 68
2.10.Chlorine .................................................. 69
2.11.Calcium ................................................... 71
2.12.Chromium .................................................. 72
2.13.Iron ...................................................... 72
2.14.Copper .................................................... 74
2.15.Zinc ...................................................... 74
2.16.Selenium .................................................. 75
2.17.Molybdenum ................................................ 75
2.18.Thallium .................................................. 76
3. Variations of Stable Isotope Ratios in Nature ............... 77
3.1. Extraterrestrial Materials ................................ 77
3.1.1. Chondrites ......................................... 78
3.1.1.1. Hydrogen .................................. 80
3.1.1.2. Carbon .................................... 80
3.1.1.3. Nitrogen .................................. 81
3.1.1.4. Sulfur .................................... 82
3.1.2. Evolved Extraterrestrial Materials ................. 82
3.1.2.1. The Moon .................................. 83
3.1.2.2. Mars ...................................... 84
3.1.2.3. Venus ..................................... 86
3.2. Isotopic Composition of the Upper Mantle .................. 86
3.2.1. Oxygen ............................................. 87
3.2.2. Hydrogen ........................................... 88
3.2.3. Carbon ............................................. 90
3.2.4. Nitrogen ........................................... 91
3.2.5. Sulfur ............................................. 92
3.3. Magmatic Rocks ............................................ 93
3.3.1. Fractional Crystallization ......................... 94
3.3.2. Differences Between Volcanic and Plutonic Rocks .... 94
3.3.3. Low-Temperature Alteration Processes ............... 94
3.3.4. Assimilation of Crustal Rocks ...................... 95
3.3.5. Basaltic Rocks from Different Tectonic Settings .... 95
3.3.6. Ocean Water/Basaltic Crust Interactions ............ 96
3.3.7. Granitic Rocks ..................................... 97
3.4. Volatiles in Magmatic Systems ............................. 97
3.4.1. Glasses ............................................ 98
3.4.1.1. Hydrogen .................................. 98
3.4.1.2. Carbon .................................... 98
3.4.1.3. Nitrogen .................................. 99
3.4.1.4. Sulfur .................................... 99
3.4.2. Volcanic Gases and Hot Springs .................... 100
3.4.2.1. Water .................................... 100
3.4.2.2. Carbon ................................... 101
3.4.2.3. Sulfur ................................... 102
3.4.3. Isotope Thermometers in Geothermal Systems ........ 103
3.5. Ore Deposits and Hydrothermal Systems .................... 103
3.5.1. Origin of Ore Fluids .............................. 105
3.5.1.1. Magmatic Water ........................... 106
3.5.1.2. Metamorphic Water ........................ 107
3.5.1.3. Formation Waters ......................... 107
3.5.2. Wall-Rock Alteration .............................. 107
3.5.3. Fossil Hydrothermal Systems ....................... 108
3.5.4. Hydrothermal Carbonates ........................... 109
3.5.5. Sulfur Isotope Composition of Ore Deposits ........ 110
3.5.5.1. Importance of Changing f02 and pH ........ 110
3.5.5.2. Recent Sulfide Deposits at Midocean
Ridges ................................... 112
3.5.5.3. Magmatic Ore Deposits .................... 112
3.5.5.4. Magmatic Hydrothermal Deposits ........... 113
3.5.5.5. Base-and Precious-Metal Vein Deposits .... 113
3.5.5.6. Volcanic-Associated Massive Sulfide
Deposits ................................. 113
3.5.5.7. Shale/Carbonate-Hosted Massive Sulfide
Deposits ................................. 114
3.5.5.8. Mississippi Valley Type Deposits ......... 114
3.5.5.9. Biogenic Deposits ........................ 114
3.5.5.10.Metamorphosed Deposits ................... 115
3.6. Hydrosphere .............................................. 115
3.6.1. Meteoric Water .................................... 116
3.6.1.1. δD-δ180 Relationship ..................... 118
3.6.1.2. Ancient Meteoric Waters .................. 119
3.6.2. Ice Cores ......................................... 119
3.6.3. Groundwater ....................................... 121
3.6.4. Isotope Fractionations During Evaporation ......... 121
3.6.5. Ocean Water ....................................... 122
3.6.6. Porewaters ........................................ 124
3.6.7. Formation Water ................................... 125
3.6.8. Water in Hydrated Salt Minerals ................... 127
3.7. Isotopic Composition of the Ocean During Geologic
History .................................................. 128
3.7.1. Oxygen ............................................ 128
3.7.2. Carbon ............................................ 130
3.7.3. Sulfur ............................................ 131
3.8. Isotopic Composition of Dissolved and Particulate
Compounds in Ocean and Freshwaters ....................... 133
3.8.1. Carbon Species in Water ........................... 133
3.8.1.1. Bicarbonate in Ocean Water ............... 133
3.8.1.2. Particulate Organic Matter (POM) ......... 134
3.8.1.3. Carbon Isotope Composition of
Porewaters ............................... 135
3.8.1.4. Carbon in Freshwaters .................... 136
3.8.2. Nitrogen .......................................... 137
3.8.3. Oxygen ............................................ 137
3.8.4. Sulfate ........................................... 138
3.9. Atmosphere ............................................... 139
3.9.1. Nitrogen .......................................... 140
3.9.2. Nitrous Oxide ..................................... 140
3.9.3. Oxygen ............................................ 141
3.9.4. Carbon Dioxide .................................... 142
3.9.4.1. Carbon ................................... 142
3.9.4.2. Oxygen ................................... 143
3.9.4.3. Long-Term Variations in the C02
Concentration ............................ 145
3.9.5. Carbon Monoxide ................................... 147
3.9.6. Methane ........................................... 147
3.9.7. Hydrogen .......................................... 148
3.9.8. Sulfur ............................................ 149
3.9.9. Mass-Independent Isotope Effects in Atmospheric
Compounds ......................................... 150
3.10.Biosphere ................................................ 150
3.10.1.Living Organic Matter ............................. 151
3.10.1.1. Bulk Carbon ............................. 151
3.10.1.2.Hydrogen ................................. 152
3.10.1.3.Oxygen ................................... 153
3.10.1.4.Nitrogen ................................. 153
3.10.1.5.Sulfur ................................... 154
3.10.2.Stable Isotopes as Indicators of Diet and
Metabolism ........................................ 154
3.10.3.Tracing Anthropogenic Organic Contaminant
Sources ........................................... 155
3.10.4.Fossil Organic Matter ............................. 155
3.10.4.1.Isotope Composition of Individual
Compounds ................................ 156
3.10.4.2.Marine Versus Terrestrial Organic
Matter ................................... 157
3.10.5.Oil ............................................... 157
3.10.6.Coal .............................................. 159
3.10.7.Natural Gas ....................................... 160
3.10.7.2.Thermogenic Gas .......................... 161
3.10.7.1.Biogenic Gas ............................. 161
3.10.7.3.Abiogenic Methane ........................ 162
3.11.Sedimentary Rocks ........................................ 163
3.11.1.Clay Minerals ..................................... 163
3.11.2.Clastic Sedimentary Rocks ......................... 165
3.11.3.Biogenic Silica and Cherts ........................ 167
3.11.4.Marine Carbonates ................................. 168
3.11.4.1.Oxygen ................................... 168
3.11.4.2.Carbon ................................... 171
3.11.5.Diagenesis ........................................ 173
3.11.5.1.Meteoric Pathway ......................... 173
3.11.5.2.Burial Pathway ........................... 173
3.11.6.Dolomites .................................. 174
3.11.7.Freshwater Carbonates ...................... 176
3.11.8.Phosphates ................................. 177
3.11.9.Iron Oxides ................................ 178
3.11.10.Sedimentary Sulfur ........................ 178
3.12.Paleoclimatology ......................................... 180
3.12.1.Continental Records ............................... 180
3.12.1.1.Ice Cores ................................ 182
3.12.2.Marine Records .................................... 185
3.12.2.1.Corals ................................... 186
3.12.3.Characteristic Climatic Events During the
Last 65 Ma ........................................ 186
3.13.Metamorphic Rocks ........................................ 188
3.13.1.Contact Metamorphism .............................. 190
3.13.2.Regional Metamorphism ............................. 191
3.13.3.Lower Crustal Rocks ............................... 192
3.13.4.Thermometry ....................................... 193
References .................................................... 197
Subject Index ................................................. 241
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