In Situ Characterization of Hydrous Silicate Melts

这项拟议的研究解决了与固体地球内岩浆和水流体相互作用有关的基本岩石学问题。其目的是描述水在整个岩浆成因过程中压力下在硅酸盐熔体中的溶解度，以及作为压力和温度函数的形态形成机制。这些数据预计将对岩浆成因条件下硅酸盐熔体和水流体的相互作用以及受挥发分溶解度影响的火成岩过程产生重要的新限制。我们的方法包括对热液金刚石顶压室中熔体-流体系统的现场目测和拉曼光谱。实验将在P.I.用密歇根大学的资金建造的一个新的实验室设施中进行。对钻石池中饱和熔体的目视观察，包括测量共存相的几何形状，将作为一种在现场量化相平衡的方法进行研究。对液态拉曼光谱的研究将包括与已知水分含量的淬火玻璃组进行仔细和广泛的比较。基于密度泛函理论的模型玻璃结构的拉曼光谱和红外光谱的初步理论计算将进一步有助于拉曼光谱的指定，并将有助于揭示振动光谱与结构和成键之间的联系。

9973050StixrudeThe proposed research addresses fundamental petrological questions regarding the interaction of magmas and aqueous fluids within the solid earth. The objectives are to characterize the solubility of water in silicate melts at pressures throughout the magma genetic regime and the speciation mechanisms as a function of pressure and temperature. These data are expected to place important new constraints on the interaction of silicate melts and aqueous fluids at magma genetic conditions and on those igneous processes that are affected by volatile solubility. Our approach consists of in situ visual observation and Raman spectroscopy of melt-fluid systems in the hydrothermal diamond anvil cell. Experiments will be performed in a new laboratory facility built by the P. I. With funds from the University of Michigan. Visual observation of saturated melts in the diamond cell including measurement of the geometries of coexisting phases will be investigated as a method for quantifying phase equilibria in situ. Investigation of the Raman spectrum of the liquid state will include careful and extensive comparison with suites of quenched glasses of known water content. Pilot theoretical calculations of the Raman and IR spectra of model glass structures based on density functional theory will further assist in the assignment of Raman bands and will help reveal the connection between vibrational spectra and structure and bonding.