The Mechanism of the Southern Junggar Cenozoic Thrusts

There are three east-west trending thrust-fold belts along the southern flank of the Junggar basin, western segments of each thrust fold belt, which are connected with the north Tianshan Piedmont fault, began forming in the middle Miocene; with the main thrust fold belts beginning forming in the late Miocene, about 10 Ma B.P. The east terminations of the thrust fold belts were formed in the Quaternary. This timing indicates the northward transportation of compressional tectonic dynamics. The initial formation time of the south Junggar thrust fold belt at the northern piedmont of Tianshan Mountains, is about 8 Ma later than that of the Kuqa thrust fold belt, at the southern piedmont of Tianshan Mountains. This suggests that the transportation of compressional tectonic dynamics took a long time through the Tianshan orogenic belt owing to its lower lithospheric strength. This contrasts sharply with the instant transportation of the tectonic dynamics through Tarim basin because of its high lithospheric strength. The spatial alternate occurrence of the delayed transportation and the instant transportation of the compressional tectonic dynamics is the main cause of intra-continental deformation patterns that resulted from the India-Asia continent-continent collision.