A Combined Structural-Petrological Analysis of the Origin and Role of Partial Melting in Orogens

造山带核心的部分熔融可能控制了地壳增厚后的流变。地球物理观测表明，活动造山带下的深部地壳，如西藏南部，与岩石圈地幔和刚性上地壳分离。这种深层地壳可能具有低粘度，并且能够流动。本项目旨在通过对加拿大科迪勒拉Shuswap变质岩心杂岩的研究，为这些概念地球动力学模型提供观测数据库。这项工作将确定变质岩的P-T时间路径，确定该路径上的部分熔融，并确定就位压力。结构和岩石学分析将限制部分熔融的条件，并将根据矿物的形状优选方向确定部分马伦壳的流动。研究结果将有助于检验和完善造山崩塌和伸展模型

9814669Teyssier Partial melting in the core of orogens likely controls the rheology of the crust subsequent to crustal thickening. Geophysical observations suggest that the deep crust under active orogens, such as southern Tibet, is decoupled from the lithospheric mantle and the rigid upper crust. This deep crust probably has a low viscosity and is able to flow. This project is aimed at providing an observational database to these conceptual geodynamic models by study of migmatites associated with the Shuswap metamorphic core complex in the Canadian Cordillera. The work will determine the P-T time paths of the metamorphic rocks, locate partial melting on this path and determine pressure of emplacement. Textural and petrologic analysis will constrain the conditions of partial melting and will determine flow of the partially mullen crust from shape preferred orientations of minerals. Results will be useful in testing and refining models of orogenic collapse and extension.***