雅鲁藏布江断裂带的构造特征

雅鲁藏布扛断裂带是印度板块与欧亚板块俯冲、碰撞的界面。通过对断裂带及邻近地质体的构造变形及大地构造背景研究，可将断裂带的发展划分成4个阶段：1)蛇绿岩侵位前的板块俯冲阶段（90Ma以前）：2)蛇绿岩侵位时的板块俯冲阶段（90Ma左右—始新世）；3)板块碰撞阶段（始新世以后)；4)走滑阶段（现代）。

THE STRUCTURAL CHARACTERISTICS OF YARLUNG ZANGBO FRACTURE ZONE

The Yarlung Zangbo fracture zone is a key unit of the Yarlung Zangbo suture zone along which the oceanic lithosphere between Indian plate and Eurasian plate subducted and the two plates finally collided. In Tibet the fracture zone is very large with a length of 1500 km and a width more than 10 km. There exist a large-scale ophiolite zone of remainder of the oceanic crust, high P/T metamorphic belt and melanges along the frature zone. Through the studies of the structural deformation of rocks in the frature zone and the nearby area, and the geotectonic setting we may distinguish the history of development of the frature zone into the following four main stages; 1) The subduction stage before the ophiolite took its present position (before 90 Ma). 2) The subduction stage during the ophiolite took its present place (about 90 Ma to Eocene Epoch). 3) The collision stage of Indian plate and Eurasian plate(after Eocene). 4) Strike sliping, the present stage.