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

造山带核部的部分熔融可能控制了地壳增厚后的地壳流变性。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解耦。这一深部地壳可能具有低粘度并能够流动。该项目旨在通过研究与加拿大科迪勒拉Shuswap变质核杂岩有关的混合岩，为这些概念性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，并在该路径上定位部分熔融，并确定侵位压力。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先取向确定部分马伦结壳的流动。研究结果将有助于检验和完善造山带坍塌和伸展的模型。

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.***