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

多相岩石是地球的构成材料，其变形、流变性和物理性质的知识对于了解地壳和地幔的构造活动(例如地震)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、流变学和地震性质的理解，并将改进后的知识应用于纯地球科学和应用地球科学中的问题。短期目标有两个：(1)确定控制应变软化、剪切局部化、微结构演化和晶格择优取向的橄榄石-斜方辉石复合材料(橄榄岩)的物理和化学过程，橄榄岩是地球上地幔中的主要岩石，在高温、高压和简单剪切条件下利用气体介质Paterson装置变形。我们预计，实验结果可能解释为什么地球上会发生板块构造形变，而金星或火星上不会发生停滞的盖状对流。(2)作为副首席科学家，深入参与了汶川地震断层科学钻探项目，该项目为钻探、取样、观察和监测龙门山断裂带(四川中国)提供了独特的机会，龙门山断裂带是不断增长的青藏高原的东缘，在2008年5月12日的8.0级地震中失败。建议通过现场观测(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物质的实验室分析和长期监测，对地震物理和化学关键问题进行研究，有望解开青藏高原主要边界如何工作的谜团。因此，这一拟议计划的一个极其重要的影响是让加拿大研究人员参与一个新的国际合作研究项目-WFSD，以提高我们对世界最大高原东部边缘地震活动的陆内断裂带的了解。

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.