Magma Redox Geochemistry

List of Contributors vii

Preface ix

1 Redox Equilibria: From Basic Concepts to the Magmatic Realm 1
Roberto Moretti and Daniel R. Neuville

Part I: Redox from the Earth's Accretion to Global Geodynamics 19

2 Redox Processes Before, During, and After Earth's Accretion Affecting the Deep Carbon Cycle 21
Vincenzo Stagno and Sonja Aulbach

3 Oxygen Fugacity Across Tectonic Settings 33
Elizabeth Cottrell, Suzanne K. Birner, Maryjo Brounce, Fred A. Davis, Laura E. Waters, and Katherine A. Kelley

4 Redox Variables and Mechanisms in Subduction Magmatism and Volcanism 63
Katy A. Evans and Andy G. Tomkins

5 Redox Melting in the Mantle 93
Stephen F. Foley

Part II: Redox at Work: From Magma Sources to Volcanic Phenomena 115

6 Ionic Syntax and Equilibrium Approach to Redox Exchanges in Melts: Basic Concepts and the Case of Iron and Sulfur in Degassing Magmas 117
Roberto Moretti

7 The Petrological Consequences of the Estimated Oxidation State of Primitive MORB Glass 139
Paul D. Asimow

8 Oxygen Content, Oxygen Fugacity, the Oxidation State of Iron, and Mid-Ocean Ridge Basalts 155
Andrew J. Berry and Hugh St.C. O'Neill

9 Chromium Redox Systematics in Basaltic Liquids and Olivine 165
Aaron S. Bell

10 The Thermodynamic Controls on Sulfide Saturation in Silicate Melts with Application to Ocean Floor Basalts 177
Hugh St.C. O'Neill

11 Redox State of Volatiles and Their Relationships with Iron in Silicate Melts: Implications for Magma Degassing 215
Nicole Métrich

12 Iron in Silicate Glasses and Melts: Implications for Volcanological Processes 233
Charles Le Losq, Maria Rita Cicconi, and Daniel R. Neuville

Part III: Tools and Techniques to Characterize the Redox and its Effect on Isotope Partitioning 255

13 How to Measure the Oxidation State of Multivalent Elements in Minerals, Glasses, and Melts? 257
Daniel R. Neuville, Maria Rita Cicconi, and Charles Le Losq

14 Oxidation State, Coordination, and Covalency Controls on Iron Isotopic Fractionation in Earth's Mantle and Crust: Insights from First-Principles Calculations and NRIXS Spectroscopy 283
Marc Blanchard and Nicolas Dauphas

15 The Role of Redox Processes in Determining the Iron Isotope Compositions of Minerals, Melts, and Fluids 303
Paolo A. Sossi and Baptiste Debret

16 Zinc and Copper Isotopes as Tracers of Redox Processes 331
Edward C. Inglis and Frédéric Moynier

17 Mineral-Melt Partitioning of Redox-Sensitive Elements 345
Guilherme Mallmann, Antony D. Burnham, and Raul O.C. Fonseca

18 Titanomagnetite - Silicate Melt Oxybarometry 369
Róbert Arató and Andreas Audétat

19 The Redox Behavior of Rare Earth Elements 381
Maria Rita Cicconi, Charles Le Losq, Grant S. Henderson, and Daniel R. Neuville

Index 399