青藏高原地区地壳—上地幔结构与巨厚地壳的形成

基于在青藏高原地区所进行的地壳与上地幔的爆炸地震探测资料;雅鲁藏布江以南和以北两条近东西向纵剖面(长约1000km左右),近南北向纵剖面(长约1200km左右),通过计算与分析,给出了青藏高原地区地壳与上地幔结构、速度分布的综合立体剖面图,发现地壳中存在著两个低速层,雅鲁藏布江是一条近于陡立的略向南倾的深大断裂带。地壳结构不论在纵向与横向都是不均匀的,最后探讨了大陆板块碰撞与巨厚地壳的形成。

THE STRUCTURE OF CRUST AND UPPER MANTLE AND FORMATION OF HUGE THICK CRUST IN QINGHAI-XIZANG PLATEAU, CHINA

This paper, on the basis of the explosion seismological data in Qinghai-Xizang Plateau, carries out analysis and calculation. These data are obtained from the profiles of south part of Yarlung Zangbo River, north part of Yarlung Zangbo River (length nearly 1000km) and profile of nearly NS strike (length nearly 1200kin). The author sets up the three-dimentional comprehensive section of structure of crust and upper mantle at Qinghai-Xizang Plateau, and finds that there exist two low-velocity layers in crust. The Yarlung Zangbo River is a steep deep-seated fracture dipping to the south. It should be pointed out that the structure of crust is laterally and longitudinally heterogenous. Finally, it can be put forward that the Himalayan zone is a transition zone between the collided plates, Indian plate and Eurasian plate. The formation of huge thick crust was discussed.