High-Pressure Elasticity of Mantle Minerals

地震学研究正在产生新的、详细的地球岩石圈和地幔三维结构图像。这些进展为绘制火星深层内部温度和化学变化提供了前所未有的可能性。这类研究的一个关键组成部分是了解地幔矿物的弹性特性，以及它们如何对结构、组成、压力和温度的变化做出反应。对于许多地幔矿物，目前对高压弹性性质的认识充其量是零碎的。在这个项目中，许多重要的地幔矿物的弹性张量将在高压下使用钻石砧细胞中的布里渊散射进行测量。主要的焦点将放在与理解在俯冲带中运行的变质过程对地震波速度的影响有关的含水相上。布里渊散射也将用于研究含铁量变的天然正辉石的高压弹性。这些结果需要了解压力和成分如何同时影响这一主要上地幔成分的弹性特性。这个研究项目将提供关于高压下材料物理学和行星内部结构和组成的基本新知识。

Seismological studies are producing new and detailed images of the three-dimensional structure of the Earth's lithosphere and mantle. These advances offer the possibility to map variations in temperature and chemistry of the planet's deep interior in unprecedented detail. A key component for such studies is knowledge of the elastic properties of mantle minerals, and how these respond to changes in structure, composition, pressure, and temperature. For many mantle minerals, current knowledge of high-pressure elastic properties is fragmentary at best. In this project, the elastic tensors of a number of important mantle minerals will be measured at high pressures using Brillouin scattering in a diamond anvil cell. A primary focus will be on hydrous phases that are relevant to understanding the effect on seismic wavespeeds of metamorphic processes operating in subduction zones. Brillouin scattering will also be used to study the high-pressure elasticity of natural orthopyroxenes with variable iron content. These results are needed to understand how pressure and composition simultaneously affect elastic properties in this major upper mantle constituent. This research program will provide fundamental new knowledge about the physics of materials at high pressures and the structure and composition of planetary interiors.