Mineral Dissolution in Silicate Melts

智力上的优点。该提案将研究硅酸盐熔体中的扩散晶体溶解？火成岩的关键过程之一。在岩浆管道、岩浆室或海洋中，夹带的捕虏体/捕猎晶和新结晶的矿物会下沉或上升，具体取决于它们相对于熔体的密度。相对运动引起对流。在下降或上升时，每种矿物颗粒都可能在对流的存在下发生溶解。硅酸盐熔体中矿物的对流溶解速率此前尚未被量化。最近的理论可以预测对流溶解速率；必要的输入参数包括系统条件（熔体和矿物成分以及温度和压力）、熔体和矿物密度、矿物的溶解度、主要平衡决定组分的扩散率以及熔体的粘度。该项目旨在约束这些参数。粘度和密度可以根据可用模型进行估计。扩散率和溶解度可以从扩散溶解实验中提取。新工作建议如下：（i）测试该理论在岩浆系统中的适用性； (ii) 进行扩散晶体溶解实验，从中提取扩散率和溶解度； (iii) 将扩散晶体溶解实验的数据量化为温度和压力的函数； (iv) 开发模型来预测自然界中的扩散和对流晶体溶解速率，重点关注给定矿物熔体系统的对流溶解速率作为温度和压力的函数。最终目标是开发一种工具来预测天然硅酸盐熔体中晶体的对流溶解速率，并应用于岩浆中异晶的消化或存活。更广泛的影响。该项目将支持研究生和本科生以及博士后研究员。国际合作者的参与将进一步促进美国与其他国家之间的科学网络。 P.I.定期将他的研究融入不同级别的教学中。

Intellectual merit. This proposal will investigate diffusive crystal dissolution in silicate melts ? one of the key processes in igneous petrogenesis. In a magma conduit, chamber or ocean, entrained xenoliths/xenocrysts and newly crystallized minerals would sink or rise depending on their density relative to the melt. The relative motion induces convection. Upon descent or ascent, each mineral grain could undergo dissolution in the presence of convection. The convective dissolution rate of minerals in silicate melts has not been quantified before. Recent theory can predict convective dissolution rates; the necessary input parameters include the system conditions (melt and mineral compositions as well as temperature and pressure), melt and mineral density, the solubility of the mineral, diffusivity of the principal equilibrium-determining component, and viscosity of the melt. This project is designed to constrain these parameters. Viscosity and density can be estimated from available models. The diffusivity and solubility may be extracted from diffusive dissolution experiments. New work is proposed work as follows: (i) testing the theory for applicability in magmatic systems; (ii) conducting diffusive crystal dissolution experiments, from which diffusivity and solubility will be extracted; (iii) quantifying data from diffusive crystal dissolution experiments as a function of temperature and pressure; (iv) developing models to predict diffusive and convective crystal dissolution rates in nature, focusing on convective dissolution rates as a function of temperature and pressure for a given mineral-melt system. The ultimate goal is to develop a tool to predict convective dissolution rate of crystals in natural silicate melts, with application to digestion or survival of xenocrysts in magmas.Broader Impacts. The project will support graduate and undergraduate students, a post-doctoral research associate. Participation of an international collaborator will further scientific networking between the United States and other nations. The P.I. regularly incorporates his research into teaching at different levels.