Magma Redox Geochemistry

1 Cover

2 Series Page

3 Title Page

4 Copyright Page

5 List of Contributors

6 Preface

7 1 Redox Equilibria 1.1. GENERAL ASPECTS AND RATIONALE 1.2. OXYGEN FUGACITY: THE CENTRALITY OF AN ELUSIVE PARAMETER 1.3. CONCLUDING REMARKS AND PERSPECTIVES ACKNOWLEDGMENTS REFERENCES

8 Part I: Redox from the Earth’s Accretion to Global Geodynamics 2 Redox Processes Before, During, and After Earth’s Accretion Affecting the Deep Carbon Cycle 2.1. THE REDOX STATE OF PLANETARY INTERIORS AND THE SPECIATION OF CARBON IN THE EARTH 2.2. OXIDATION STATE OF EARTH’S BUILDING BLOCKS AND EARLY DIFFERENTIATION 2.3. MANTLE OXIDATION STATE OVER TIME AND ITS EFFECT ON THE C–O–H VOLATILE SPECIATION 2.4. THE MANTLE GREAT OXIDATION EVENT: FACT OR ARTEFACT? ACKNOWLEDGMENTS REFERENCES 3 Oxygen Fugacity Across Tectonic Settings 3.1. INTRODUCTION 3.2. SAMPLE SELECTION, METHODOLOGY, AND DESIGN OF THIS STUDY 3.3. RESULTS 3.4. DISCUSSION 3.5. CONCLUSIONS AND FUTURE DIRECTIONS ACKNOWLEDGMENTS METHODS APPENDIX REFERENCES 4 Redox Variables and Mechanisms in Subduction Magmatism and Volcanism 4.1. INTRODUCTION 4.2. REDOX VARIABLES 4.3. MECHANISMS 4.4. DISCUSSION ACKNOWLEDGMENTS REFERENCES 5 Redox Melting in the Mantle 5.1. INTRODUCTION 5.2. MANTLE MELTING WITH VOLATILE COMPONENTS 5.3. REDOX MELTING 5.4. COMPOSITIONS OF MELTS FORMED BY REDOX MELTING 5.5. THE OXIDATION STATE IN THE MANTLE LITHOSPHERE, ASTHENOSPHERE, AND SUBDUCTION ZONES 5.6. DISCUSSION 5.7. CLOSING COMMENTS ACKNOWLEDGMENTS REFERENCES

9 Part II: Redox at Work: From Magma Sources to Volcanic Phenomena 6 Ionic Syntax and Equilibrium Approach to Redox Exchanges in Melts: Basic Concepts and the Case of Iron and Sulfur in Degassing Magmas 6.1. INTRODUCTION 6.2. IONIC SYNTAX, SPECIATION STATE AND THE MELT/GLASS NETWORK: STATE OF THE ART AND CONCEPTUAL FRAMEWORK 6.3. REDOX EVOLUTION AND MAGMATIC DEGASSING 6.4. DISCUSSION 6.5. CONCLUSIONS CODE AVAILABILITY ACKNOWLEDGMENTS REFERENCES 7 The Petrological Consequences of the Estimated Oxidation State of Primitive MORB Glass 7.1. INTRODUCTION 7.2. MODELING METHODS AND SAMPLE SELECTION 7.3. RESULTS 7.4. SUMMARY AND PROSPECTS ACKNOWLEDGMENTS REFERENCES 8 Oxygen Content, Oxygen Fugacity, the Oxidation State of Iron, and Mid‐Ocean Ridge Basalts 8.1. OXYGEN CONTENT, OXYGEN FUGACITY, AND THE OXIDATION STATE OF IRON 8.2. MID‐OCEAN RIDGE BASALTS ACKNOWLEDGMENTS REFERENCES 9 Chromium Redox Systematics in Basaltic Liquids and Olivine 9.1. INTRODUCTION 9.2. MEASURING C RVALENCE IN GEOLOGICMATERIALS WITH C R‐K EDGE XANES SPECTROSCOPY 9.3. C R‐REDOX SYSTEMATICS IN SILICATELIQUIDS: WHAT WE KNOW AND DON’T KNOW 9.4. C R‐VALENCE SYSTEMATICS INEQUILIBRIUM LIQUID‐OLIVINE PAIRS 9.5. CONCLUDING REMARKS ACKNOWLEDGMENTS REFERENCES 10 The Thermodynamic Controls on Sulfide Saturation in Silicate Melts with Application to Ocean Floor Basalts 10.1. INTRODUCTION 10.2. SULFIDE CAPACITY 10.3. THE THERMODYNAMIC MEANING OF THE SULFIDE CAPACITY 10.4. A NEW PARAMETERIZATION OF SULFIDE CAPACITY FOR BASALTIC MELTS 10.5. SULFIDE CONTENT AT SULFIDE SATURATION (SCSS) 10.6. APPLICATION TO MID‐OCEAN RIDGE AND SIMILAR BASALTS 10.7. THE SULFUR FUGACITY ( f S 2) OF OCEAN FLOOR BASALTS 10.8. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 11 Redox State of Volatiles and Their Relationships with Iron in Silicate Melts 11.1. INTRODUCTION 11.2. WATER CONCENTRATION IN MELT AND ITS EFFECT ON REDOX 11.3. THE SULFUR SPECIES AND THE REDOX (FE 3+/∑FE Ratio) OF SILICATE MELTS 11.4. NATURAL SYSTEMS: MAGMA DEGASSING AND REDOX 11.5. CONCLUDING REMARKS ACKNOWLEDGMENTS REFERENCES 12 Iron in Silicate Glasses and Melts 12.1. INTRODUCTION 12.2. IRON DISTRIBUTION IN THE DIFFERENT TERRESTRIAL ENVELOPES 12.3. REDOX EQUILIBRIUM IN MELTS 12.4. PHYSICAL PROPERTIES: HIGHLIGHTS ON DENSITY AND VISCOSITY 12.5. INFLUENCES ON CRYSTALLIZATION AND DEGASSING IN MAGMATIC SYSTEMS 12.6. CONCLUDING REMARKS ACKNOWLEDGMENTS REFERENCES

10 Part III: Tools and Techniques to Characterize the Redox and its Effect on Isotope Partitioning 13 How to Measure the Oxidation State of Multivalent Elements in Minerals, Glasses, and Melts? 13.1. INTRODUCTION 13.2. WET‐CHEMICAL ANALYSES 13.3. ELECTRONIC MICROPROBE 13.4. MÖSSBAUER SPECTROSCOPY 13.5. OPTICAL ABSORPTION SPECTROSCOPY 13.6. X‐RAY ABSORPTION SPECTROSCOPY 13.7. RAMAN SPECTROSCOPY 13.8. IN SITU REDOX DETERMINATION AT HIGH TEMPERATURE OR AT HIGH PRESSURE 13.9. CONCLUSION ACKNOWLEDGMENTS REFERENCES 14 Oxidation State, Coordination, and Covalency Controls on Iron Isotopic Fractionation in Earth’s Mantle and Crust 14.1. INTRODUCTION 14.2. THEORY: EQUILIBRIUM ISOTOPIC FRACTIONATION FROM VIBRATIONAL PROPERTIES 14.3. CALCULATION OF VIBRATIONAL PROPERTIES 14.4. IRON ISOTOPE STUDIES BASED ON NRIXS OR DFT 14.5. COMPARISON OF EQUILIBRIUM FRACTIONATION FACTORS DERIVED FROM VARIOUS TECHNIQUES 14.6. PARAMETERS CONTROLLING EQUILIBRIUM FRACTIONATION FACTORS 14.7. SELECTED APPLICATIONS TO THE INTERPRETATION OF IRON ISOTOPIC VARIATIONS IN IGNEOUS ROCKS 14.8. CONCLUSIONS AND PERSPECTIVES ACKNOWLEDGMENTS REFERENCES 15 The Role of Redox Processes in Determining the Iron Isotope Compositions of Minerals, Melts, and Fluids 15.1. INTRODUCTION 15.2. PRINCIPLES AND NOMENCLATURE 15.3. METHODS FOR THE CALIBRATION OF IRON ISOTOPE FRACTIONATION FACTORS 15.4. FUNDAMENTAL CONTROLS ON ISOTOPIC FRACTIONATION BETWEEN MINERALS, MELTS, AND FLUIDS 15.5. EFFECT OF REDOX PROCESSES IN INFLUENCING IRON ISOTOPE FRACTIONATION IN NATURAL SYSTEMS 15.6. CONCLUSION ACKNOWLEDGMENTS REFERENCES 16 Zinc and Copper Isotopes as Tracers of Redox Processes 16.1. INTRODUCTION 16.2. THE DETERMINATION OF CU AND ZN ISOTOPE RATIOS 16.3. THEORETICAL AND EXPERIMENTAL CONSTRAINTS ON CU AND ZN ISOTOPE BEHAVIOR IN RELATION TO REDOX PROCESSES 16.4. APPLICATION OF CU AND ZN TO TRACE REDOX PROCESSES IN NATURAL SYSTEMS 16.5. SUMMARY AND CONCLUSIONS ACKNOWLEDGMENTS REFERENCES 17 Mineral‐Melt Partitioning of Redox‐Sensitive Elements 17.1. INTRODUCTION 17.2. THEORETICAL BACKGROUND 17.3. TRANSITION METALS (Fe, Cr, Ti, V) 17.4. RARE EARTHS (Ce, Eu) 17.5. URANIUM (U) 17.6. SIDEROPHILE ELEMENTS (Mo, W, Re, Pt GROUP ELEMENTS) 17.7. CONCLUDING REMARKS ACKNOWLEDGMENTS REFERENCES 18 Titanomagnetite – Silicate Melt Oxybarometry 18.1. INTRODUCTION 18.2. OXYBAROMETERS RELATED TO TITANOMAGNETITE 18.3. OXYBAROMETERS BASED ON MINERAL EQUILIBRIA INVOLVING TITANOMAGNETITE 18.4. OXYBAROMETERS BASED ON ELEMENT PARTITIONING BETWEEN TITANOMAGNETITE AND SILICATE MELT 18.5. APPLICATION OF TITANOMAGNETITE‐BASED OXYBAROMETERS TO NATURAL SILICIC ROCKS 18.6. CONCLUSIONS ACKNOWLEDGMENTS REFERENCES SUPPLEMENTARY REFERENCES 19 The Redox Behavior of Rare Earth Elements 19.1. INTRODUCTION 19.2. GEOCHEMISTRY OF RARE EARTH ELEMENTS 19.3. MULTIVALENT RARE EARTH ELEMENTS 19.4. CONCLUSIONS AND PERSPECTIVES ACKNOWLEDGMENTS REFERENCES

11 Index

12 End User License Agreement

1 Chapter 3 Table 3.1 Results and Method Summary. Table A1 Major element criteria for “terrestrial” lavas between QFM ‐3 and ... Table A2 Standard error (σ est) of three f O 2parameterizations.

2 Chapter 8Table 8.1 The percentage of O in different forms, or condensed by various re...

3 Chapter 10Table 10.1 Experimental studies used in parameterizing the sulfide content ...Table 10.2 Sulfur analyses in natural OFB glass VG2 (USNM 111240/52) by ele...Table 10.3 SCSS experiments in Re capsules at 1400°C, 1.5 GPa using the sta...Table 10.4 SCSS model sensitivities (anhydrous model).

4 Chapter 12Table 12.1 Example of optical basicity Λ of common network formers and modi...Table 12.2 Viscosity data of DiFe0, DiFe6, DiFe12, and DiFe18 diopside melt...

5 Chapter 13Table 13.1 Fe and Mn crystalline compounds reported in Fig. 13.6. Experimen...Table 13.2 Summarize of analytical techniques and their advantages.

6 Chapter 14Table 14.1 Iron β ‐factors ( 56/54Fe) derived from first‐principles calcu...