Earth material science: from brittle fault zones of the upper crust to plastic flow of the upper mantle

多相岩是地球的组成材料，了解它们的变形、流变学和物理性质对理解地壳和地幔的构造活动（如地震）和动力学至关重要。我的研究计划的长期目标是提高我们对地壳和地幔岩石的变形行为，流变学和地震特性的理解，并将改进的知识应用于纯地球科学和应用地球科学的问题。短期目标有两个方面：(1)利用气-介质Paterson仪器确定控制橄榄石-正辉石复合材料（橄榄岩）在高温、高压和简单剪切条件下变形的应变软化、剪切局部化、微观结构演化和晶格优先取向的物理和化学过程。我们期望实验结果可以解释为什么板块构造类型的变形发生在地球上，而不是在金星或火星上发生停滞的盖子类型的对流。(2)作为副首席科学家，深入参与汶川地震断裂带科学钻探（WFSD）项目，为青藏高原东部边缘的龙门山断裂带（中国四川）提供了独特的钻探、取样、观测和监测机会，该断裂带在2008年5月12日的8.0级地震中失败。通过现场观测（地质和地球物理探测）、井下实验、从断裂带及其围岩中回收的岩心材料的实验室分析以及长期监测，对地震物理和化学的关键问题进行研究，有望解决青藏高原主要边界如何工作的谜团。因此，这个计划的一个极其重要的影响是让加拿大的研究人员参与到一个新的国际合作研究项目中来——WFSD，以提高我们对世界上最大的高原东部边缘地震活跃的大陆内断裂带的理解。

Knowledge of the deformation, rheology and physical properties of polyphase rocks, which are the Earth's constitutive materials, is critically important for understanding the tectonic activity (e.g., earthquakes) and dynamics of the crust and mantle. The long-term objectives of my research program are to improve our understanding of the deformation behavior, rheology and seismic properties of the crust and mantle rocks, and to apply the improved knowledge to problems in pure and applied Earth Sciences. The short-term objectives are two-fold: (1) Determination of physical and chemical processes controlling strain softening, shear localization, microstructural evolution and lattice-preferred orientation of olivine-orthopyroxene composites (peridotite), which is the dominant rock in the Earth's upper mantle, deformed at high temperature, high pressure and simple shear conditions using a gas-medium Paterson apparatus. We expect that the experimental results may explain why plate tectonic style of deformation occurs on the Earth, but not on Venus or Mars where stagnant lid style of convection occurs. (2) Intensive involvement, as the vice Chief-scientist, in the Wenchuan earthquake Fault Scientific Drilling (WFSD) project which offers a unique opportunity to drill, sample, observe and monitor the Longmen Shan fault zone (Sichuan China), the eastern margin of the growing Tibetan plateau, which failed in the M8.0 earthquake on 12 May 2008. The proposed investigations on key problems about earthquake physics and chemistry through in-situ observations (geological and geophysical probing), down-hole experiments, laboratory analyses of core materials recovered from the fault zone and its country rocks, and long-term monitoring, hopefully lead to a resolution of the mystery of how the major boundary of the Tibetan Plateau works. Thus, an extremely important impact of this proposed program is to involve the Canadian researchers in a novel international collaborative research project - WFSD, to improve our understanding of seismically active intracontinental fault zones at the eastern margin of the world's largest plateau.