青藏高原的形成与隆升

FORMAION AND UPLIFING OF THE QINGHAI-TIBET PLATEAU

青藏高原的形成与隆升问题是个十分复杂、倍受地球科学家关注的问题。它被认为是冈瓦纳大陆与欧亚大陆长期相互作用的结果。青藏高原是由6个地体相继增生到亚洲大陆上的一个组合，这些地体之间的边界被5条缝合带所限定。造山作用自北向南相继变年轻。青藏高原是特提斯的主要范畴，它可以分成3个区域，分别代表了3个阶段主洋盆位置。特提斯北区位于昆仑山和祁连山，它的遗迹是第五缝合带，在大陆基底上于震旦纪形成裂谷，奥陶纪闭合。特提斯中区位于可可西里-巴颜喀喇，古生代晚期以来在弧后盆地基础上继续破裂、扩张，典型的洋壳形成于石炭-二叠纪，这个时期的洋称古特提斯，它的遗迹为第三和第四缝合带。特提斯南区位于青藏高原南部，雅鲁藏布江缝合带代表了它的主洋盆遗迹，班公-怒江缝合带代表了它的弧后盆地。青藏高原的隆升以多阶段、非均匀、不等速为特征，大体上可分成4个阶段，即45～38，25～17，13～8和3～0Ma。虽然到目前为止已经提出了多种模式来解释高原的形成与隆升，但是这一问题迄今仍然没有解决。文中笔者根据多年来地质。地球物理和地球化学研究成果和近年来新的实验研究结果，提出了叠加压扁热动力模式来解释青藏高原的形成与隆升机制。

The questions about the formation and uplifting of the Qinghai - Tibet Plateau arevery complex, and they are very attractive to geologists in the world. The Plateau resultedfrom the interaction of the Gondwanaland and the Eurasia continent in a long time. The Qing-hai- Tibet Plateau was assembled to Asia through successive accretion by six terranes. Theboundaries between these terranes are defined by five suture zones. From north to south theorogenic events took place successvely. The Qinghai -Tibet Plateau is the main domain ofTethys. It can be divided into three regions to represent the main locations in the three differ-ent stages. The northern Tethys Region is now occupied by the Kunlun and the Qilian Moun-tains, its remnant is the Fifth suture zone. The rift initiated after the basement had beenformed in Sinian and was closed in Ordovician. The central Tethys Region lies in Hoh Xil-Bayan har. Since Late Palaeozoic, the back-arc bathyal basin continued to break and spread.The trpical oceanic crust was eventually formed in Carboniferous and Permian. The Ocean dur-ing that period is named the Paleo-Tethys, of which the remnant is the Third and the Fourthsuture zone. The southern Tethys Region lies in the southern part of the Qinghai-TibetPlateau. The Yarlung Zangbe suture zone may represent the trace of its its main oceanic basin,and the Banggong-Nujiang suture zone the trace of the back-arc basin. The uplifting of theQinghai- Tibet Plateau is characterised by multiple stage, inhomogeneity and nonuniform ve-locity. It can apparently be divided into four stages, i. e. 45~38, 25~17, 13 ~8 and 3~0Ma, respectively. Although several models have already been proposed, the questions concern-ing the formtion and uplifting of the Qnghai - Tibet Plateau have not been resolved. Based onnew experimental results and data of geology, geophysics and geochemistry, a new model, i. e.superimposed flattening and thermal dynamic model, is put forward for the formation and up-lifting mechanism of the Qinghai - Tibet Plateau in this paper.