Phase Equilibria of Sulfur and Chlorine Bearing Phases in Magmas

点击翻译按钮获取中文摘要

Ghiorso and KressEAR- 9980518Research is proposed to develop thermodynamic models for the solubility of sulfur- and chlorine-bearing phases (gasses, liquids and solids) in molten silicate liquids. Emphasis will be directed toward naturally occurring melts of "magmatic" compositions. Results will be incorporated into the software package MELTS. The proposed model for sulfur will include both the reduced and oxidized forms of dissolved melt species and will account for the solubility minimum associated with intermediate oxidation states. It will also incorporate our recent studies on the solubility of sulfide liquids in silicate melts. The initial goal will be development of a comprehensive model to predict the oxidation state of sulfur in silicate melt as a function of temperature, bulk composition, and oxygen/sulfur fugacity. Experimental work in high-temperature, one-atmosphere gas-mixing furnaces will be performed to augment existing published information on both sulfur and chlorine solubility relations. In parallel with these efforts, a preliminary thermodynamic model for solid solutions of the minerals sodalite, nosean, and hauyne will be developed, as these minerals represent important reservoirs of chlorine and sulfur in magmas of low silica activity. Applications of this work will be directed at illuminating sulfur and chlorine solubility and phase relations in natural composition melts under geologic temperature and pressure conditions.