Mineral Dissolution in Silicate Melts

硅酸盐熔体中的矿物溶解

• 批准号: 1019440
• 负责人: Youxue Zhang
• 金额: $ 35万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1019440&HistoricalAwards=false
• 关键词: Mineral; Dissolution; Silicate; Melts

One of the fundamental questions for understanding volcanic and deep magmatic processes is how fast minerals grow or dissolve in a magma under a given condition. However, the seemingly simple question has only begun to be addressed recently. This award will allow the investigator to continue to undertake an experimental and theoretical modeling study of mineral dissolution and growth in silicate melts. Diffusive and convective crystal dissolution of plagioclase and quartz (two of the most major minerals) in magmas will be investigated in the next grant period. This study will provide predictive methods to calculate dissolution rates of specific minerals in silicate melts as a function of temperature, pressure and other conditions. Furthermore, the crystallization history of magma oceans during early evolution of Moon and Earth will be modeled. Mineral dissolution and growth are a fundamental process in igneous petrogenesis. In a magma conduit, chamber or ocean, entrained crystals and xenoliths 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 would undergo dissolution (if the ambient melt is undersaturated with respect to the mineral) or growth (if there is oversaturation) in the presence of convection. This study's ultimate aim is to provide a practical method for estimating convective mineral dissolution and growth rates. It is proposed to obtain the necessary data and develop relations to directly calculate diffusive and convective dissolution rates of two mafic minerals: olivine and clinopyroxene, in basaltic melts as a function of temperature, pressure, and melt composition. In this next grant period, the investigator and his team will investigate the dissolution kinetics of two felsic minerals: plagioclase in basaltic melts and quartz in felsic melts, including the relative role of interface reaction and mass transport in controlling the dissolution rates. Furthermore, with experimental data and theoretical understanding accumulated over the years, they will develop models for the crystallization history and evolution of lunar and terrestrial magma oceans. The new work will significantly improve our fundamental understanding of magmatic processes and magma ocean evolution.

了解火山和深层岩浆过程的基本问题之一是在给定条件下矿物质在岩浆中生长或溶解的速度有多快。 然而，这个看似简单的问题直到最近才开始得到解决。 该奖项将使研究人员能够继续进行硅酸盐熔体中矿物溶解和生长的实验和理论建模研究。 下一个资助期内将研究岩浆中斜长石和石英（两种最主要的矿物）的扩散和对流晶体溶解。 这项研究将提供预测方法来计算硅酸盐熔体中特定矿物的溶解速率作为温度、压力和其他条件的函数。 此外，还将对月球和地球早期演化过程中岩浆海洋的结晶历史进行建模。矿物溶解和生长是火成岩的基本过程。 在岩浆管道、岩浆室或海洋中，夹带的晶体和捕虏体以及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，每个矿物颗粒都会在对流的存在下经历溶解（如果环境熔体相对于矿物而言不饱和）或生长（如果存在过饱和）。 这项研究的最终目的是提供一种估算对流矿物溶解和生长速率的实用方法。 建议获得必要的数据并建立关系，以直接计算两种镁铁质矿物：橄榄石和单斜辉石在玄武岩熔体中的扩散和对流溶解速率，作为温度、压力和熔体成分的函数。 在下一个资助期内，研究人员和他的团队将研究两种长英质矿物的溶解动力学：玄武岩熔体中的斜长石和长英质熔体中的石英，包括界面反应和质量传递在控制溶解速率中的相对作用。 此外，凭借多年来积累的实验数据和理论理解，他们将开发月球和陆地岩浆海洋的结晶历史和演化模型。 这项新工作将显着提高我们对岩浆过程和岩浆海洋演化的基本理解。