Frequency Sweep Acoustic Interferometry: Measurement of Silicate Melt Compressibility and Density at High Temperature and Pressure

岩浆液体的状态方程（P-V-T关系）对于在扩张脊和俯冲带下的部分熔融和熔体运输的定量模型是至关重要的，而扩张脊和俯冲带是海洋和大陆地壳形成的地方。深部地幔部分熔融的热力学模型面临的一个主要挑战是缺乏高压下岩浆液体密度的信息。最大的不确定性是压力对熔体压缩性的依赖，以及挥发性成分在高压下如何影响熔体密度。本提案的主要目标是测量许多地质相关液体的压缩性和密度，作为压力和温度的系统函数，在内部加热压力中使用频率扫描声干涉仪。这些数据将提供从光谱研究中获得的液体微观结构与其宏观性质之间的定量联系。因此，这些数据将大大提高地球和材料科学中不同光谱工具和分子建模的实用性和洞察力。高压下熔体的声速数据也将有助于改进对地壳和地幔地震速度变化的解释，因为地壳和地幔可能存在部分熔体。研究生将获得部分资助。他们将接受的跨学科培训为他们在地球科学领域的学术生涯或涉及高科技材料的工业生涯做好了极好的准备。

An equation of state (P-V-T relation) for magmatic liquids is critical for quantitative models of partial melting and melt transport beneath spreading ridges and subduction zones, where oceanic and continental crust are formed. A major challenge to thermodynamic models of partial melting in the deep mantle is the lack of information on the density of magmatic liquids at high pressure. The largest uncertainties are with the pressure dependence to melt compressibility and with how volatile components affect melt density at high pressure. The primary objective of this proposal is to measure the compressibility and density of numerous geologically relevant liquids as a systematic function of pressure and temperature, using a frequency-sweep acoustic interferometer in an internally heated pressure. These data will provide a quantitative link between the microscopic structure of liquids, obtained from spectroscopic studies, and their macroscopic properties. Thus these data will greatly enhance the utility and insights provided by different spectroscopic tools and molecular modeling within the earth and material sciences. The sound velocity data on melts at high pressure will also be helpful for improved interpretation of seismic velocity variations in the crust and mantle, where partial melt may be present. Graduate students will be partially supported by this grant. The interdisciplinary nature of the training that they will receive is excellent preparation for either an academic career in the earth sciences or an industry career involving high-tech materials.