Mon. May 23, 2016 9:00 AM - 10:30 AM 201B (2F)

Convener:*Bjorn Mysen(Geophysical Laboratory, Carnegie Inst. Washington), Eiji Ohtani(Department of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University), Toru Inoue(Geodynamics Research Center, Ehime University), Chair:Eiji Ohtani(Department of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University)

Hydrogen-rich volatiles are critical partners of the dynamic Earth. They play a central role throughout the Earth's interior from shallow hydrothermal systems in oceanic and subduction zone settings, in zones of mantle melting, at the fluid-enriched slab/upper mantle interface, in the mantle transition zone and lower mantle to the core-mantle boundary, and the Earth's core. This session will focus on how hydrogen-rich volatiles affect the geochemistry, mineralogy, and geophysics of the Earth's interior through natural observations, laboratory experiments, and numerical modeling. H2O dominates in most settings in the present Earth. H2 is found in shallow hydrothermal environments resulting from alteration of ultramafic rocks. Molecular H2 and hydrogen-bearing reduced nitrogen and carbon species (i.e, methane and ammonia) can be dominant in the deep mantle. Hydrides are candidates for core components. Water, H2, and CH4 were the principal species in the silicate Earth during the first few million years of its history. Hydrogen-containing fluids, melts, and minerals affect mineralogy, phase relations, and numerous other physical and chemical properties and processes in the Earth's interior. Characterization of these processes is accomplished by combining observation, experiment and modeling. To this end, this session will include discussion of (i)How volatiles control the Earth's dynamic processes including recycling and mass transfer processes, (ii) Stability relations, chemical and physical properties of hydrous and hydride crystalline and molten phases and application of such information to geophysical properties, including seismic behavior, of the Earth's interior, (iii) Hydrogen solubility in oxides and metals at deep earth interior conditions and its effect on mantle rheology and equation-of-state, and (iv) Hydrogen and melt crystallization and element distribution and redistribution in the silicate Earth.