Elastic Wave Velocity Measurements on Unquenchable Mantle Phases

李宝生，李宝生-0003340本课题主要研究两种不可淬熄地幔相--斜顽火辉石高压相和钙钛矿型硅酸钙相的弹性性质。该项目将利用安装在布鲁克海文国家实验室（BNL）NSLS光束线X17 B1处的DIA型立方砧高压装置（SAM 85），使用同步加速器X射线照相术和X射线衍射技术以及高压超声干涉测量法。研究人员将使用X射线照相技术记录样品图像，同时测量通过样品的旅行时间，提供计算速度所需的样品长度。当通过X-射线衍射证实不可淬灭相的形成时，在随后的P-T条件下同时测量压力、温度、体积、Vp、Vs和样品的长度（P-V-T-Vp-Vs-L）将为状态方程分析和确定弹性体积模量和剪切模量的压力和温度导数提供数据。单斜辉石和硅酸钙钙钛矿相的这些数据对于解释地震观测以确定地幔的成分和矿物学至关重要。

Li, BaoshengEAR-0003340 This proposal is focused on the study the elastic properties of two unquenchable mantle phases, high pressure phase of clinoenstatite, and calcium silicate perovskite. This project will utilize the DIA-type cubic anvil high pressure apparatus (SAM85) installed at beamline X17B1 of the NSLS at Brookhaven National Laboratory (BNL) using synchrotron X-ray radiography and X-ray diffraction techniques in conjunction with high pressure ultrasonic interferometry. The investigators will use an X-ray radiography technique to record the sample image at the same time as the travel time through the sample is measured, providing the length of the sample needed for the calculation of velocity. When the formation of the unquenchable phase is confirmed by X-ray diffraction, simultaneous measurement of pressure, temperature, volume, Vp, Vs, and the length of the sample (P-V-T-Vp-Vs-L) at subsequent P-T conditions will provide data for both equation of state analysis and the determination of the pressure and temperature derivatives of the elastic bulk and shear moduli. Such data for clinopyroxene and calcium silicate perovskite phases are crucial for interpreting seismic observations to determine the composition and the mineralogy of the mantle.