Phase Transformations Involving Olivine, -Phase and Spinel in the Mantle Transition Zone: Experimental Studies of Transformation Mechanisms in Mg2SiO4...

9506481 Brearley本项目的目标是详细研究在与模式地幔地热和俯冲大洋岩石圈有关的一系列PT条件下，Mg_2SiO_4和(Mg，Fe)_2SiO_4高压地幔相变的机制。这项研究将继续努力描绘不同的转换机制可能在地幔中运行的压力-温度机制，并确定哪些因素可能导致转换机制的变化。研究结果对研究上地幔、动力学，特别是俯冲洋板的流变性和深源地震机制具有重要的地质意义。该项目将包括使用多个砧座高压装置进行高压动力学实验，以及使用光学和电子显微镜进行详细的微观结构研究。将特别强调使用透射电子显微镜技术，特别是电子衍射和高分辨率电子显微镜来阐明转化机制。

9506481 Brearley The objective of this project is to study in detail the mechanisms of the high pressure mantle phase transformations of the Mg2SiO4 and (Mg,Fe)2 SiO4 under a range of PT conditions relevant to the model mantle geotherm and subducting oceanic lithosphere. The study will continue efforts to delineate the pressure-temperature regimes over which different transformation mechanisms may operate in the Earth's mantle and identify what factors may cause changes in the transformation mechanism. The results have important geological implications for upper mantle, dynamics, especially the rheological behavior of subducting oceanic slabs and the mechanisms of deep focus earthquakes. The project will involve high pressure kinetic experiments using a multi anvil high pressure apparatus coupled with detailed microstructural studies using optical and electron microscopy. Special emphasis will be placed on the use of transmission electron microscope techniques, particularly electron diffraction and high resolution electron microscopy to elucidate the transformation mechanisms.