青藏高原叶城-狮泉河路线地质特征及区域构造演化

TECTONIC EVOLUTION ALONG THE GEOTRAVERSE FROM YECHENG TO SHIQUANHE

叶城-狮泉河地质路线位于青藏高原西部,全长1056km,它穿过了西昆仑山和喀喇昆仑山东端。中法两国科学家于1989年7月—8月联合考察了这条路线,根据蛇绿岩、古生物、沉积相、岩浆活动、构造变形及变质作用,将路线经过地段,自北而南分为5个地体及四条蛇绿岩缝合带,这些地体时代自北而南有逐渐变新的趋势。

The geotraverse from Yecheng to Shiquanhe on the western Qinghai-Tibet Plateau, totally 1056km in length, passes through the western Kunlun Mountains and the eastern end of the Karakorum Mountains. The Chinese-French scientists investigated this geotraverse from July 10 to August 17, 1989. Based on the outcropping ophiolites, biogeographical provinces, facies of sediments and types of formation, ages and features of magmatism, ages and features of tectonic deformation and meta-morphism, from north to south the region through which the geotraverse passes may be divided into five terranes, i. e.: the north Kunlun terrane, south Kunlun terrane, Tianshuihai terrane, Karakorum-Qiangtang terrane and Shiquanhe terrane. They are separated by our ophiolitic suture zones respectively, which are the Kuda suture zone, Mazar-Kangxiwar suture zone, Hongshahu suture zone and Bangong Lake suture zone from north to south. The formation ages of these terranes and suture zones have a tendency to become younger from north to south. Based on those data, the authors propose a model of the tectonic formation and evolution along this geotra-verse. As the age of the Kuda ophiolite range from 900-400Ma, it is proposed that Proto-Tethys existed in the west Kunlun Mountains. Since the Indian subcontinent collided with the Asian continent in the Eocene, the intracontinental deformation of the Qinghai-Tibet plateau has been very intense, signified by crustal shortenning in a north-south direction and vertical thickening.