STABLE ISOTOPE GEOCHEMISTRY<br>FOURTH COMPLETELY REVISED UPDATED AND ENLARGED EDITION<br>JOCHEN HOEFS<br><br><br><br><br><br><br>Table of Contents<br>Chapter ı<br>Theoretical and Experimental Principles<br>1.1 General Characteristics of Isotopes...................... ı<br>1.2 Isotope Effects......................................................... 3<br>1.3 Isotope Fractionation Processes........................... 5<br>1.3.1 Isotope Exchange.................................................... 5<br>1.3.1.1 Fractionation Factor (a)........................................ 7<br>1.3.1.2 The Delta Value (6)................................................. 8<br>1.3.1.3 Evaporation-Condensation Processes.................. 9<br>1.3.2 Kinetic Effects......................................................... 10<br>1.3.3 Diffusion.................................................................. 11<br>1.3.4 Other Factors Influencing Isotopic Fractionations 14<br>1.3.4.1 Chemical Composition.......................................... 14<br>1.3.4.2 Crystal Structure.................................................... 14<br>1.3.4.3 Non-Mass-Dependent Isotope Effects.................. 14<br>1.3.5 Isotope Geothermometers..................................... 15<br>1.3.5.1 Theoretical Calculations........................................ 16<br>1.3.5.2 Experimental Calibrations..................................... 17<br>1.4 Basic Principles of Mass Spectrometry................ 19<br>1.5 Standards................................................................. 22<br>1.6 General Remarks on Sample Handling................ 24<br>1.7 New Microanalytical Techniques.......................... 25<br>1.7.1 Laser Microprobe................................................... 25<br>1.7.2 Gas Chromatography Combined with Gas Mass<br>Spectrometry.......................................................... 25<br>1.7.3 Secondary Ion Mass Spectrometry....................... 26<br>Chapter 2<br>Isotope Fractionation Mechanisms<br>of Selected Elements<br>2.1 Hydrogen......................................o...-..ooo--oo--o 2.8<br>2.1.1 Preparation Techniques and Mass Spectrometric<br>Measurements..................................ooooo-............... 29<br> <br>Standards................................................................. 29<br>Fractionation Mechanisms.................................... 30<br>Equilibrium Exchange Reactions.......................... 32<br>Kinetic Isotope Effects........................................... 33<br>Other Fractionation Effects................................... 34<br>Lithium.................................................................... 34<br>Boron....................................................................... 36<br>Carbon..................................................................... 38<br>Preparation Techniques......................................... 39<br>Standards................................................................. 39<br>Fractionation Mechanisms.................................... 39<br>Inorganic Carbon System...................................... 40<br>Carbon Isotope Fractionations During<br>Photosynthesis........................................................ 41<br>2.4.4 Interactions Between the Carbonate-Carbon<br>Reservoir and Organic Carbon Reservoir............ 42<br>2.5 Nitrogen.................................................................. 43<br>2.6 Oxygen..................................................................... 47<br>2.6.1 Preparation Techniques......................................... 47<br>2.6.2 Standards................................................................. 49<br>2.6.3 Fractionation Mechanisms.................................... 49<br>2.6.4 Fluid-Rock Interactions........................................ 53<br>2.7 Silicon...................................................................... 56<br>2.8 Sulfur....................................................................... 57<br>2.8.1 Preparation Techniques......................................... 58<br>2.8.2 Fractionation Mechanisms.................................... 59<br>2.8.2.1 Bacterial Reduction of Sulfate............................... 59<br>2.8.2.2 Thermochemical Reduction of Sulfate................. 60<br>2.8.2.3 Isotope Exchange Reactions.................................. 60<br>2.9 Chlorine................................................................... 62<br>Chapter 3<br>Variations of Stable Isotope Ratios in Nature<br>3.1 Extraterrestrial Materials...................................... 65<br>3.1.1 Meteorites................................................................ 65<br>3.1.1.1 Hydrogen................................................................. 67<br>3.1.1.2 Carbon..................................................................... 68<br>3.1.1.3 Nitrogen.................................................................. 69<br>3.1.1.4 Sulfur....................................................................... 69<br>3.1.2 The Moon and the Neighboring Planets Mars and<br>Venus....................................................................... 70<br>3.1.2.1 The Moon................................................................ 70<br>3.1.2.2 Mars......................................................................... 71<br>3.1.2.3 Venus....................................................................... 72<br> <br>3.1.3 Comets..................................................................... 72<br>3.1.4 Interplanetary Dust Particles................................ 72<br>3.2 Isotopic Composition of the Upper Mantle......... 73<br>3.2.1 Oxygen..................................................................... 74<br>3.2.2 Hydrogen................................................................. 75<br>3.2.3 Carbon..................................................................... 76<br>3.2.4 Sulfur....................................................................... 78<br>3.2.5 Nitrogen.................................................................. 79<br>3.3 Magmatic Rocks..................................................... 79<br>3.3.1 Fractional Crystallization...................................... 80<br>3.3.2 Differences Between Volcanic and Plutonic Rocks 80<br>3.3.3 Low-Temperature Alteration Processes................ 80<br>3.3.4 Assimilation of Crustal Rocks............................... 81<br>3.3.5 Basaltic Rocks from Different Tectonic Settings. 81<br>3.3.6 Ocean Water/Basaltic Crust Interactions............. 83<br>3.3.7 Granitic Rocks ........................................................ 84<br>3.4 Volatiles in Magmatic Systems.............................. 84<br>3.4.1 Glasses..................................................................... 85<br>3.4.1.1 Hydrogen................................................................. 85<br>3.4.1.2 Carbon..................................................................... 85<br>3.4.1.3 Nitrogen.................................................................. 86<br>3.4.1.4 Sulfur....................................................................... 86<br>3.4.2 Volcanic Gases and Hot Springs ........................... 87<br>3.4.2.1 Water........................................................................ 87<br>3.4.2.2 Carbon..................................................................... 88<br>3.4.2.3 Sulfur....................................................................... 89<br>3.4.3 Isotope Thermometers in Geothermal Systems.. 89<br>3.5 Ore Deposits and Hydrothermal Systems............ 90<br>3.5.1 Origin of Ore Fluids...............................................

91<br>3.5.1.1 Seawater................................................................... 92<br>3.5.1.2 Meteoric Waters...................................................... 93<br>3.5.1.3 Juvenile Water......................................................... 93<br>3.5.1.4 Magmatic Water...................................................... 93<br>3.5.1.5 Metamorphic Water............................................... 94<br>3.5.1.6 Formation Waters................................................... 94<br>3.5.2 Wall-Rock Alteration.............................................. 94<br>3.5.3 Fossil Hydrothermal Systems................................ 95<br>3.5.4 Hydrothermal Carbonates..................................... 96<br>3.5.5 Sulfur Isotope Composition of Ore Deposits ...... 97<br>3.5.5.1 Importance of Changing fO2 and pH ................... 97<br>3.5.5.2 Reservoir Effect...................................................... 99<br>3.5.5.3 Recent Sulfide Deposits at Mid-Ocean Ridges..... 100<br>3.5.5.4 Magmatic Ore Deposits......................................... 100<br>3.5.5.5 Magmatic Hydrothermal Deposits....................... 101<br>3.5.5.6 Base and Precious Metal Vein Deposits................ 101<br>3.5.5.7 Volcanic-Associated Massive Sulfide Deposits.... 101<br> <br>3.5.5-8 Shale/Carbonate-Hosted Massive Sulfide Deposits 102<br>3.5.5.9 Mississippi Valley Type Deposits.......................... 102<br>3.5.5.10 Biogenic Deposits................................................... 103<br>3.5.5.11 Metamorphosed Deposits ..................................... 103<br>3.6 Hydrosphere............................................................ 103<br>3.6.1 Meteoric Water........................................................ 104<br>3.6.1.1 6D-618O Relationship............................................. 106<br>3.6.1.2 Ancient Meteoric Waters........................................ 107<br>3.6.2 Ice Cores.................................................................. 107<br>3.6.3 Groundwater........................................................... 109<br>3.6.4 Isotope Fractionations During Evaporation........ no<br>3.6.5 Ocean Water............................................................ 111<br>3.6.6 Pore Waters ............................................................. 113<br>3.6.7 Formation Water..................................................... 113<br>3.6.8 Water in Hydrated Salt Minerals........................... 115<br>3.7 Isotopic Composition of the Ocean During<br> Geological History.................................................. 116<br>3.7.1 Oxygen..................................................................... 117<br>3.7.2 Carbon..................................................................... 117<br>3.7.3 Sulfur....................................................................... 118<br>3.8 Isotopic Composition of Dissolved and Particulate<br> Compounds in Ocean and Fresh Waters.............. 120<br>3.8.1 Carbon Species in Water........................................ 120<br>3.8.1.1 Bicarbonate in Ocean Water.................................. 120<br>3.8.1.2 Particulate Organic Matter.................................... 121<br>3.8.1.3 Carbon Isotope Composition of Pore Waters...... 122<br>3.8.1.4 Carbon in Fresh Waters.......................................... 123<br>3.8.2 Nitrogen.................................................................. 123<br>3.8.3 Oxygen..................................................................... 124<br>3.8.4 Sulfate...................................................................... 124<br>3.9 Atmosphere............................................................. 125<br>3.9.1 Nitrogen.................................................................. 126<br>3.9.2 Oxygen..................................................................... 127<br>3.9.3 Ozone....................................................................... 127<br>3.9.4 Carbon Dioxide...................................................... 127<br>3.9.4.1 Carbon..................................................................... 127<br>3.9.4.2 Oxygen..................................................................... 129<br>3.9.4.3 Long-Term Variations in the CO2 Concentration 130<br>3.9.5 Methane................................................................... 131<br>3.9.6 Hydrogen................................................................. 131<br>3.9.7 Sulfur....................................................................... 132<br>3.10 Biosphere................................................................. 133<br>3.10.1 Living Organic Matter............................................ 133<br>3.10.1.1 Bulk Carbon............................................................ 133<br>3.10.1.2 Chemical Components of Plant Material............. 135<br> <br>3-1O.2 Isotope Fractionations of Other Elements During<br>Photosynthesis........................................................ 135<br>3.10.2.1 Hydrogen................................................................. 135<br>3.10.2.2 Oxygen..................................................................... 136<br>3.10.2.3 Nitrogen.................................................................. 137<br>3.10.2.4 Sulfur....................................................................... 137<br>3.10.3 Stable Isotopes as Indicators of Diet and<br>Metabolism ................................r............................ 137<br>3.10.4 Recent Organic Matter........................................... 138<br>3.10.5 Fossil Organic Matter in Sediments ..................... 138<br>3.10.6 Oil............................................................................. 140<br>3.10.7 Coal.......................................................................... 141<br>3.10.8 Natural Gas ............................................................. 141<br>3.10.8.1 Biogenic Gas............................................................ 143<br>3.10.8.2 Thermogenic Gas................................................... 143<br>3.10.8.3 Abiogenic Methane................................................ 144<br>3.11 Sedimentary Rocks................................................. 145<br>3.11.1 Clay Minerals.......................................................... 145<br>3.11.2 Clastic Sedimentary Rocks.................................... 145<br>3.11.3 Biogenic Silica and Cherts..................................... 148<br>3.11.4 Marine Carbonates................................................. 149<br>3.11.4.1 Oxygen..................................................................... 149<br>3.11.4.2 Carbon..................................................................... 153<br>3.11.5 Diagenesis of Limestones ...................................... 154<br>3.11.5.1 Meteoric Pathway................................................... 155<br>3.11.5.2 Burial Pathway........................................................ 155<br>3.11.6 Dolomites................................................................ 156<br>3.11.7 Freshwater Carbonates........................................... 157<br>3.11.8 Phosphates.............................................................. 158<br>3.11.9 Iron Oxides.............................................................. 159<br>3.11.10 Sedimentary Sulfur................................................ 160<br>3.12 Metamorphic Rocks............................................... 161<br>3.12.1 Regional Metamorphism....................................... 164<br>3.12.2 Lower Crustal Rocks .............................................. 165<br>3.12.3 Contact Metamorphism......................................... 166<br>3.12.4 Thermometry.........................................................

167<br>References............................................................... 169<br>Subject Index.......................................................... 197<br>