Deformation and Microstructural Evolution of Harzburgite

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的板块构造是地球科学中的统一理论，描述了地球？的表面沿沿着移动。 这些板块边界对社会极为重要，因为它们是许多自然灾害的焦点，包括地震和火山。 为了理解板块边界的行为，我们必须了解这些边界内物质的物理性质。 这个奖项是资助一项努力，以模拟材料在这些条件下的行为。 为了模拟这种行为，需要许多专门的设备，包括大型气动或液压机，以产生高压条件。 实验分析使用高分辨率扫描电子显微镜中的特定类型的相机进行。 通过对天然变形橄榄岩的研究，可以发现，变形橄榄岩的晶格择优取向（LPO）、晶粒大小和形状以及相分离等微观结构，在构造演化过程中，由于岩石的变形，使得岩石的晶格择优取向、晶粒大小和形状以及相分离等微观结构发生了变化。（或混合），继续演变超过几乎所有变形实验中获得的应变。 由于变形微构造不仅影响流变学，而且影响地质和地球物理资料的解释，因此研究变形微构造的形成和演化具有重要意义。正在进行两个系列的实验。(1)第一组实验研究了纯橄榄岩和方辉橄榄岩在变形到非常大的应变期间的显微结构和流变演化（#947;10）。(2)第二个系列的实验将引入额外的复杂性，通过改变实验过程中的剪切感，以分析变形的运动学和微观结构和流变演化的动力学之间的反馈。 这些实验是在具有扭转能力的Paterson型气体介质装置中进行的;另外的实验将在目前正在建造的旋转Drickamer装置中进行。 将使用电子背散射衍射（EBSD）以及其他光学和电子显微镜技术进行微观结构分析。 本研究中收集的数据将提高我们对（1）第二阶段对地幔变形的影响，（2）地幔剪切带中的物理过程，以及（3）俯冲带和洋中脊等角流环境中的地震各向异性的理解。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)Plate tectonics is a unifying theory in the Earth sciences that describes the processes by which Earth?s surface shifts along narrow boundaries. These plate boundaries are of tremendous importance to society, as they represent the foci of many natural hazards, including earthquakes and volcanoes. To understand the behavior of plate boundaries it is essential that we understand the physical properties of material within these boundaries. This award is funding an effort to simulate the behavior of materials at these conditions. To simulate this behavior, a number of specialized apparatuses are needed, including large pneumatic or hydraulic presses to generate high pressure conditions. Analysis of the experiments takes place using a particular type of camera in a high-resolution scanning electron microscope. The data that are collected in this study will help us understand the physical processes that occur along plate margins, which will inform a broad spectrum of geophysical research.It is evident from studies of naturally deformed peridotites that deformation microstructures such as lattice-preferred orientation (LPO), grain-size and shape, and phase segregation (or mixing), continue to evolve beyond the strains achieved in almost all deformation experiments. As deformation microstructures affect both rheology and the interpretation of geological and geophysical data, it is important for us to study their formation and evolution. Two series of experiments are being conducted. (1) The first set of experiments investigates microstructural and rheological evolution of dunite and harzburgite during deformation to very large strains (γ10). (2) The second series of experiments will introduce additional complexity by changing the sense of shear during experiments to analyze the feedback between the kinematics of deformation and the kinetics of microstructural and rheological evolution. These experiments are being conducted in a Paterson-type gas medium apparatus with torsion capability; additional experiments will be conducted in a rotational Drickamer apparatus currently under construction. Microstructural analysis will be conducting using electron backscatter diffraction (EBSD), as well as other optical and electron microscope-based techniques. The data collected in this study will improve our understanding of (1) the effects of secondary phases on deformation in the mantle, (2) physical processes in mantle shear zones, and (3) seismic anisotropy in corner flow environments such as subduction zones and mid-ocean ridges.