In Situ Characterization of Hydrous Silicate Melts

9973050 Stixrude拟议的研究解决了有关固体地球内岩浆和含水流体相互作用的基本岩石学问题。其目的是表征在整个岩浆成因制度和物种形成机制的压力和温度的函数的压力下，在硅酸盐熔体中的水的溶解度。这些数据预计将把重要的新的限制在岩浆成因条件下的硅酸盐熔体和含水流体的相互作用，并对那些受挥发性溶解度的火成岩过程。我们的方法包括在原位目视观察和拉曼光谱的熔体-流体系统的热液金刚石对顶砧单元。实验将在私人研究所建造的新实验室设施中进行。基金来自密歇根大学。 在金刚石细胞，包括共存相的几何形状的测量饱和熔体的视觉观察将被调查作为一种方法，用于量化原位相平衡。 液态的拉曼光谱的研究将包括与已知水含量的淬火玻璃套件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和红外光谱的初步理论计算将进一步有助于拉曼谱带的归属，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.