青藏高原第五缝合带的发现与论证

DISCOVERY AND EVIDENCE OF THE FIFTH SUTURE ZONE OF QINGHAI-XIZANG PLATEAU

１９８７年以来，中国科学院青藏高原综合科学考察队开展了对喀喇昆仑山和昆仑山的多学科综合性科学考察．本文根据这次考察的大量资料，论证了青藏高原第五缝合带的存在．考察资料表明，在西昆仑山存在一个被称作原特提斯的海洋，这个洋是在劳亚大陆南部基底上破裂、扩张并形成于震旦纪至奥陶纪时期（大约８００－４５０Ｍａ）．原特提斯海洋闭合于加里东造山运动，并形成现在所见的库地－苏巴什缝合带的残迹，即青藏高原第五缝合带，从而完善了青藏高原的地质历史和构造演化．

Kunlun mountain was believed the typical illustration of Hercynian or Indo-Sinian orogens previous. Since 1987, supported by both the Chinese Academy of Sciences and National Natural Science Foundation of China, a multi-disciplinary scientific expedition was conducted in Karakorum and Kunlun mountain ranges by Integrated Scientific Expeditional Team to Qinghai-Xizang plateau, Chinese Academy of Sciences, which obtained much new information. This paper is carried out on the basis of the results of this expedition. There was an ocean called the Proto-Tethys in western Kunlun, which was blocked and opened on southern Laurasia continental basements and developed mainly from Sinian to Ordovician(about 800-450Ma). The Proto-Tethys was closed by the Caledonian orogeny and formed now a remnant of Kudi-Shubashi suture zone which called fifth suture zone of Qinghai-Xizang plateau. Therefore geological history and tectonic evolution of Qinghai-Xizang plateau are clear.