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

地球物质科学：从上地壳脆性断裂带到上地幔塑性流动

• 批准号: 121552-2010
• 负责人: Ji, Shaocheng
• 金额: $ 2.55万
• 依托单位: École Polytechnique de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=507798
• 关键词: Earth; material; science; brittle; fault

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.

多相岩石是地球的构成材料，了解其变形、流变学和物理性质对于理解构造活动（例如，地震）和地壳和地幔的动力学。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）使用气体介质帕特森仪器，确定控制橄榄石-斜方辉石复合体（橄榄岩）的应变软化、剪切局部化、显微结构演变和晶格择优取向的物理和化学过程，橄榄岩是地球上地幔的主要岩石，在高温、高压和简单剪切条件下变形。我们期望实验结果可以解释为什么地球上发生板块构造型的变形，而金星或火星上没有发生停滞盖型的对流。(2)作为副首席科学家，积极参与汶川地震断层科学钻探项目，该项目提供了一个独特的机会，对龙门山断层带（中国四川）进行钻探、取样、观察和监测，龙门山断层带是不断增长的青藏高原的东缘，在2008年5月12日的8.0级地震中破裂。 建议通过现场观测（地质和地球物理探测）、井下实验、对断裂带及其围岩的岩心材料进行实验室分析和长期监测，对地震物理和化学的关键问题进行研究，以期解决青藏高原主边界的奥秘。因此，这一拟议方案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，以提高我们对世界上最大高原东缘地震活跃的陆内断层带的理解。