PALEOMAGNETIC STUDY AND TECTONIC EVOLUTION OF XINJIANG AND ITS NEIGHBORING REGIONS

Based on the paleomagnetic study of Tarim,Junggar and Kunlun Mountains region,the paleomagnetic polar wandering path amd paleolatitude data of Tarim,Junggar and Qinghai Tibet plates from Paleozoic to Cenozoic have been obtained.The Tarim plate was not formed until Sinian,since it was preliminary formed in Late Sinian,it has undergone twice rapid northward shifting and once rapid southward shifting.The Junggar plate remained a single microplate in Early Paleozoic,it combined with Kazakhistan plate in Late Paleozoic and formed the Kazakhistan Junggar plate.Tarim plate still was one part of Gondwanaland before Sinian,it graduately separated from Gondwana in Early Paleozoic and shifted northward rapidly,It first collided with Junggar plate in the early stage of Late Paleozoic and became a accretionary wedge of Southern Laurasia.The blocks located between Laurasia and Gondwana were called Cathaysia group.From the end of Late Paleozoic to early of Mesozoic,the blocks combined with Laurasia at the south margin.The Paleo Tethys was not formed until the early stage of Early Paleozoic,the blocks distributed in the range of Gondwanaland and located at the equator of south hemispher.In Middle late Silurian,these blocks began to shift northward rapidly,the ocean was enlarged and formed the Paleo Tethys.Which formed a framwork of three lands with two oceans between.Permian was an important stage for the evolution of Tethys tectonics,from Late Jurassic to Early Cretaceous,the Kunlun terrane,Chaidamu block and Tarim block collided and formed one block,the collision between Tarim and Chaidamu at the early stage of Early Jurassic made the Paleo Tethys extinct.The new Tethys was created in the middle stage of Early Jurassic.In the middle stage of Late Cretaceous,Himalaya Indian block moved northward quickly,which narrowed the new Tethys and wiped it out at the late stage of Tertiary,the evolutional history of Tethys tectonic domain was ended.The paleogeography of Paleozoic,Mesozoic and Cenozoic of China can be reconstructed based on the paleomagnetic data.At the early stage of Late Paleozoic,the Paleo Asian Ocean,paleo Atlantic and paleo Tethys were formed by sea floor spreading,the main plates were also formed at the same time.Since China is located in one of the main convergent regions of plates,it made the tectonics of China very complex.The present researchers have realized that the plates can not be divided by one simple line.There is a very complex tectonics between the plates.The sutures of plales have the chronzone feature.