Physical Properties at High Pressure and Temperature: Implications for Mantle Stratification and Dynamics

了解矿物的主要物理性质的高压和高温行为是继续努力了解地幔内对流的重要组成部分。由于我们目前的大部分理解仍然基于硅酸盐矿物的假设和外推的弹性和热性质，因此很难确定地幔的径向地震模型是否意味着化学分层。PI建立了一个实验室，用于在高压和高温下测量候选地幔组分的关键物理性质。激光诱导声子光谱学已与金刚石砧细胞技术相结合，用于测量高压下矿物的弹性常数和热扩散系数。最近报道了橄榄石至7 GPa的结果。将这种对各种矿物的测量扩展到过渡带和下地幔压力状态（12至25 GPA）是本工作的主要目标。将尝试同时在高温高压下进行测量。

Knowledge of the high pressure and high temperature behavior of key physical properties of minerals is an essential ingredient in the continuing effort to understand convection within Earth's mantle. Since much of our current understanding is still based on assumed and extrapolated elastic and thermal properties of silicate minerals, it remains difficult to determine whether or not radial seismic models for the mantle imply chemical stratification. The PI has constructed a laboratory for the measurement at high pressure and temperature of key physical properties of candidate mantle constituents. Laser-Induced Phonon Spectroscopy has been coupled with diamond anvil cell technology to measure elastic constants and thermal diffusivity of minerals at high pressure. Results for olivine to 7 GPa have recently been reported. Extension of such measurements on a variety of minerals to a transition zone and lower mantle pressure regime (12 to 25 GPA) is a principle goals of the present work. Measurements at simultaneous high temperature and pressure will be attempted.