Experimental Studies of Volatile-Bearing Minerals and Rocks Relevant to Subduction Zones, the Mantle and Core

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

EAR-0310342 Knittle Abstract The investigator's high pressure studies are oriented towards constraining the behavior of volatiles (particularly water, hydrogen, carbon and nitrogen) within planet Earth. The objectives are to derive constraints on: (1) the volatile content of Earth's core, as evaluated from the high pressure behavior of volatile-bearing iron alloys; (2) how hydrogen and carbon are bound into crystalline assemblages at mantle conditions; and (3) the structure and properties of volatile-rich magmas at high pressures. The methods employed in this work combine vibrational spectroscopy (infrared and Raman spectroscopies) and x-ray diffraction as probes of samples held within the diamond anvil cell, which generate ultra-high pressures. Heating at high pressures is accomplished with either external heaters or laser-heating of samples. The intellectual merits of the proposed experiments include producing fundamental insights into the carbon and hydrogen budgets of planet Earth; evaluating the means by which atmospheric and hydrospheric constituents are degassed from the Earth's interior and then reintroduced into the planet through subduction; and the phase relations and properties of Earth's iron-rich core. The broader impacts of this study includes developing a better understanding of the genesis of Earth's oceans and atmosphere, as well as developing a framework for assessing how two of the most cosmochemically abundant elements, hydrogen and carbon, behave under the extreme conditions of planetary interiors.