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）对于洋壳和陆壳形成的扩张脊和俯冲带下的部分熔融和熔体输运的定量模型至关重要。 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。 最大的不确定性是与压力的熔体压缩性和挥发性组分如何影响熔体密度在高压下的依赖性。该建议的主要目的是测量的压缩性和密度的许多地质相关的液体作为一个系统的函数的压力和温度，使用扫频声波干涉仪在内部加热的压力。 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更好地解释地壳和地幔中可能存在部分熔体的地震速度变化。 研究生将部分得到这笔赠款的支持。他们将接受的培训的跨学科性质是为地球科学的学术生涯或涉及高科技材料的行业生涯做好准备。

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.