Phase Equilibria of Sulfur and Chlorine Bearing Phases in Magmas

Ghiorso和KressEAR-9980518研究提出了含硫和含氯相(气体、液体和固体)在熔融硅酸盐液体中溶解度的热力学模型。重点将放在“岩浆”成分的自然熔融上。结果将被合并到软件包Melts中。建议的硫模型将包括溶解熔体物种的还原和氧化形式，并将考虑与中间氧化态相关的最小溶解度。它还将纳入我们最近对硫化物液体在硅酸盐熔体中的溶解度的研究。最初的目标将是开发一个全面的模型，以预测硅酸盐熔体中硫的氧化状态随温度、体积组成和氧/硫逸度的函数。将在高温、单气氛气体混合炉中进行实验工作，以补充现有发表的关于硫和氯的溶解度关系的信息。在进行这些工作的同时，还将开发方钠铝石、方钠石和海因矿物固溶体的初步热力学模型，因为这些矿物代表着低二氧化硅活度岩浆中氯和硫的重要储存库。这项工作的应用将针对阐明地质温度和压力条件下天然组成熔体中硫和氯的溶解度和相关系。

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.