Elastic Wave Velocity Measurements on Unquenchable Mantle Phases

Li，宝盛EAR-0003340本方案重点研究了两个不可熄灭的地幔相，即斜辉石高压相和硅酸钙钙钛矿的弹性性质。该项目将利用安装在布鲁克海文国家实验室(BNL)NSLS光束线X17B1处的DIA型立方砧座高压装置(SAM85)，使用同步辐射X射线照相和X射线衍射技术，并结合高压超声波干涉测量。研究人员将使用X射线照相技术在测量通过样品的旅行时间的同时记录样品图像，提供计算速度所需的样品长度。当X射线衍射证实不熄灭相的形成时，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-Vs-L)将为状态方程分析和确定弹性体模和剪切模压力和温度导数提供数据。这些关于单斜辉石和钙硅酸盐钙钛矿相的数据对于解释地震观测以确定地幔的成分和矿物学是至关重要的。

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.