Hydrous Magmatic Processes: An Experimental Study of Structure and Properties of Hydrous Silicate Melts, In-Situ, at High Pressure and Temperature

智力上的优点。地球和类地行星中的质量和能量传递过程涉及高温和高压下的熔化和结晶。作为对我们理解这种岩浆作用的重要贡献，提出了一个研究计划：(1)在高压和高温条件下对水化硅酸盐熔体的结构进行现场实验研究；(2)确定熔体结构如何控制水化熔体的物理化学性质。这项研究的动机是，几乎所有的岩浆过程都受到其H2O含量的强烈影响。水在硅酸盐熔体中溶解机理的实验表征通常依赖于作为硅酸盐熔体替代物的水合玻璃所获得的数据。然而，水合熔体向水合玻璃的转变会引起结构变化。玻璃数据不能用于对含水熔体的物理化学性质进行定量建模。因此，在本研究中，我们将测定在高压和高温下，二元金属氧化物-二氧化硅和三元金属氧化物-氧化铝-二氧化硅体系的水合熔体结构。这些简单的模型系统将被用来识别和分离支配结构和结构-性质关系的单个化学成分。将通过拉曼光谱和傅里叶变换红外光谱对水热金刚石压腔中的水合熔体进行结构研究，这些熔体分别在25-1000摄氏度和0.1 MP-1.5 GPA的温度和压力范围内工作。熔体数据将通过使用拉曼光谱、傅里叶变换红外光谱和核磁共振光谱方法确定水合玻璃的结构而得到增强。对熔体及其玻璃的结构分析也将有助于我们理解玻璃的形成过程，并提供信息来评估硅酸盐玻璃结构在多大程度上可以作为熔体结构的替代。更广泛的影响。在拟议研究的三年期间，该研究计划将平均涉及1-2名博士后研究人员和2名本科生和高中生。学生和博士后将参与实验项目的执行，并将实验结果应用于岩石形成过程的表征。此外，国际和平研究所与S室内研究所(日本三萨市)和地球物理研究所(法国巴黎)的研究人员继续和扩大国际合作将进一步支持拟议的研究计划。

Intellectual merit. Mass and energy transfer processes in the Earth and terrestrial planets involve melting and crystallization at high temperature and pressure. As an important contribution to our understanding of such magmatic processes, a research program is proposed (1) to conduct an experimental study, in-situ, at high pressures and temperatures of the structure of hydrous silicate melts, and (2) to determine of how melt structure governs physicochemical properties of hydrous melts. The research is motivated by the fact nearly all magmatic processes are strongly affected by their H2O content. Experimental characterization of solution mechanisms of H2O in silicate melts commonly relies on data obtained from hydrous glasses serving as proxies for silicate melts. However, transformation of hydrous melts to hydrous glasses causes structural changes. The glass data cannot be used for quantitative modeling of physicochemical properties of hydrous melts. In this study, we will, therefore, determine hydrous melt structure of binary metal oxide-silica and ternary metal oxide-alumina-silica systems while the materials are at high pressure and temperature. These simple model systems will be used in order to identify and isolate individual chemical components governing structure and structure-property relationships. Structural studies will be conducted via Raman and FTIR spectroscopy of hydrous melts in a hydrothermal diamond anvil cell operating in the 25-1000C and 0.1MP-1.5 GPa temperature, and pressure ranges, respectively. The melt data will be augmented by determination of hydrous glass structure using Raman, FTIR, and NMR spectroscopic methods. Structure analysis of melts and their glasses will also contribute to our understanding of glass-forming processes and provide information to assess the extent to which silicate glass structure can be used as a proxy for melt structure. Broader impacts. The research program will involve, on average, 1-2 post-doctoral researchers and 2 undergraduate and high school students throughout the 3-year period of the proposed research. The students and post-docs will be involved in execution of experimental projects and in the application of the experimental results to characterization of rock-forming processes. In addition, continuing and expanding international collaboration between the PI and researchers from the Institute for the Study of the Earth''s Interior (ISEI, Misasa, JAPAN) and Institut de Physique du Globe (Paris, FRANCE) will further aid the proposed research program.