青藏高原北部地体划分及其构造演化

TERRAIN SUBDIVISION OF THE NORTHERN QINGHAI-XIZANG (TIBET) PLATEAU AND ITS TECTONIC EVOLUTION

采用构造地层地体分析方法，对沿格尔木－额济纳旗地学断面（长近９００ｋｍ，宽１００ｋｍ）走廊域研究区内的地质构造进行了重点研究．以现有的资料，把研究区划分出由３个地体群组成的３个大的构造单元，即它们由南往北是青藏地体群、古西域地体群、准噶尔－南蒙地体群．这些地体群经历早古生代的裂解、离散，晚古生代的拼合，中生代以来进入陆内活动阶段时又经历两次（即－次由北往南，另－次由南往北）强构造挤压作用，致使地壳变形和缩短，形成现今青藏高原北部的构造格架．

Applying the tectonostratigraphic-terrain analysis,we carried out an anatomical study on the geological structure of a strip (900 km long and 100 km wide )along the Golmud-Ejin Qi Geotraverse.Based on existing data, we recognized three tectonic units consisting of terrain groups:from south to north, the Qinghai-Xizang (Tibet) terrain group, Guxiyu terrain group and Junggar-South Mongolia terrain group. These groups underwent rifting and dispersing in the Early Paleozoic and amalgamation in the Late Paleozoic. Since the Mesozoic, there have been two stages of intense compression (one southward and the other northward) in the period of intracontinental activity, leading to the crustal deformation and shortening that gave rise to the present tectonic framework of the northern Qinghai-Xizang (Tibet) plateau and its adjacent regions.