The Geochemical Consequences of Fluid Immiscibility on Ore Deposition (Earth Science)

流体包裹体证据存在于许多经济矿床中，表明流体不混溶的开始与成矿的开始之间存在联系。流体不混溶对矿物平衡和矿石沉积的影响可以通过将Bowers和Helgeson(1983)的H2O和CO2的修正Redlich-Kuong活度模型并入EQ3/6化学平衡和质量转移计算机程序(Wolery，1978,1979,1983)来评估。该模型将考虑体系中各组分的损失、两相分离对流体的pH值和化学形态的影响以及矿物的稳定性和沉积。此外，还将考虑稳定的同位素在液体和气相之间的分配以及同时形成矿物相。给出了在250oC时，流体通过压降与H2O-CO2混相间隙相交的初步计算。该模型预测了当二氧化碳从系统中流失以及碳酸盐矿物沉积时，pH的预期上升。其中一条路径导致在流体不混溶开始时沉积大量的金属硫化物。鲍尔斯博士将教授一门名为地质过程热力学的课程，就她工作的各个方面举办一系列研究生讲座，并为哈佛大学带来适合这门课程的完整的地球化学建模计算机能力，并供学生进一步用于自己的研究项目。该项目进一步推动了VPW计划的目标，即：(1)为妇女提供机会，在NSF资助的工程和科学学科中发展她们的职业生涯；(2)通过提高受雇于工业、政府和学术机构的女科学家和工程师的知名度，鼓励妇女追求科学和工程事业。通过鼓励妇女参与科学，这是对国家未来科学活力的宝贵投资。

Fluid inclusion evidence exists in a number of economic ore deposits suggesting a link between the onset of fluid immiscibility and initiation of ore deposition. The effects of fluid immiscibility on mineral equilibria and ore deposition can be assessed by incorporation of a modified Redlich-Kwong activity model for H2O and CO2 from Bowers and Helgeson (1983) into the EQ3/6 chemical equilibria and mass transfer computer code (Wolery, 1978, 1979, 1983). This model will account for loss of components from the system and the effects of two-phase separation on pH and chemical speciation of the fluid, as well as mineral stabilities and deposition. In addition, stable isotope partitioning between liquid and vapor phases and simultaneously forming mineral phases will be considered. Preliminary calculations for a fluid intersecting the H2O - CO2 miscibility gap by a drop in pressure at 250oC are presented. The model predicts the expected rise in pH upon CO2 loss from the system as well as deposition of carbonate minerals. One of the paths results in deposition of substantial amounts of metal sulfides at the onset of fluid immiscibility. Dr. Bowers will teach a course entitled Thermodynamics of Geologic Processes, present a series of graduate lectures on various aspects of her work, and bring to Harvard complete computer capabilities for geochemical modeling appropriate to the course and for further student use on their own research projects. This project furthers VPW program objectives which are (1) to provide opportunities for women to advance their careers in engineering and in the disciplines of science supported by NSF and (2) to encourage women to pursue careers in science and engineering by providing greater visibility for women scientists and engineers employed in industry, government, and academic institutions. By encouraging the participation of women in science, it is a valuable investment in the Nation's future scientific vitality.