Magma Redox Geochemistry

Explores the many facets of redox exchanges that drive magma's behavior and evolution, from the origin of the Earth until todayThe redox state is one of the master variables behind the Earth's forming processes, which at depth concern magma as the major transport agent. Understanding redox exchanges in magmas is pivotal for reconstructing the history and compositional make-up of our planet, for exploring its mineral resources, and for monitoring and forecasting volcanic activity.Magma Redox Geochemistry describes the multiple facets of redox reactions in the magmatic realm and presents experimental results, theoretical approaches, and unconventional and novel techniques.Volume highlights include:* Redox state and oxygen fugacity: so close, so far* Redox processes from Earth's accretion to global geodynamics* Redox evolution from the magma source to volcanic emissions* Redox characterization of elements and their isotopesThe American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

List of Contributors viiPreface ix1 Redox Equilibria: From Basic Concepts to the Magmatic Realm 1Roberto Moretti and Daniel R. NeuvillePart I: Redox from the Earth's Accretion to Global Geodynamics 192 Redox Processes Before, During, and After Earth's Accretion Affecting the Deep Carbon Cycle 21Vincenzo Stagno and Sonja Aulbach3 Oxygen Fugacity Across Tectonic Settings 33Elizabeth Cottrell, Suzanne K. Birner, Maryjo Brounce, Fred A. Davis, Laura E. Waters, and Katherine A. Kelley4 Redox Variables and Mechanisms in Subduction Magmatism and Volcanism 63Katy A. Evans and Andy G. Tomkins5 Redox Melting in the Mantle 93Stephen F. FoleyPart II: Redox at Work: From Magma Sources to Volcanic Phenomena 1156 Ionic Syntax and Equilibrium Approach to Redox Exchanges in Melts: Basic Concepts and the Case of Iron and Sulfur in Degassing Magmas 117Roberto Moretti7 The Petrological Consequences of the Estimated Oxidation State of Primitive MORB Glass 139Paul D. Asimow8 Oxygen Content, Oxygen Fugacity, the Oxidation State of Iron, and Mid-Ocean Ridge Basalts 155Andrew J. Berry and Hugh St.C. O'Neill9 Chromium Redox Systematics in Basaltic Liquids and Olivine 165Aaron S. Bell10 The Thermodynamic Controls on Sulfide Saturation in Silicate Melts with Application to Ocean Floor Basalts 177Hugh St.C. O'Neill11 Redox State of Volatiles and Their Relationships with Iron in Silicate Melts: Implications for Magma Degassing 215Nicole Métrich12 Iron in Silicate Glasses and Melts: Implications for Volcanological Processes 233Charles Le Losq, Maria Rita Cicconi, and Daniel R. NeuvillePart III: Tools and Techniques to Characterize the Redox and its Effect on Isotope Partitioning 25513 How to Measure the Oxidation State of Multivalent Elements in Minerals, Glasses, and Melts? 257Daniel R. Neuville, Maria Rita Cicconi, and Charles Le Losq14 Oxidation State, Coordination, and Covalency Controls on Iron Isotopic Fractionation in Earth's Mantle and Crust: Insights from First-Principles Calculations and NRIXS Spectroscopy 283Marc Blanchard and Nicolas Dauphas15 The Role of Redox Processes in Determining the Iron Isotope Compositions of Minerals, Melts, and Fluids 303Paolo A. Sossi and Baptiste Debret16 Zinc and Copper Isotopes as Tracers of Redox Processes 331Edward C. Inglis and Frédéric Moynier17 Mineral-Melt Partitioning of Redox-Sensitive Elements 345Guilherme Mallmann, Antony D. Burnham, and Raul O.C. Fonseca18 Titanomagnetite - Silicate Melt Oxybarometry 369Róbert Arató and Andreas Audétat19 The Redox Behavior of Rare Earth Elements 381Maria Rita Cicconi, Charles Le Losq, Grant S. Henderson, and Daniel R. NeuvilleIndex 399