THE TRANSFER ZONE WITHIN INTRA-CONTINENT SUBDUCTION OROGENIC BELT IN THE TIANSHAN, NORTHWEST CHINA

The Tianshan Mountains is a composite orogenic belt. The intra-continent subduction occurred under the influence of distant compressure of subduction and collision taking place between the Indian plate and the Eurasia plate in the Mesozoic-Cenozoic. The Tarim block and the Junggar block subducted in the opposite direction beneath the Tianshan Mountains. The mountains was lifted rapidly and thrust-folded from central to north and south. Intra-continent subduction foreland basins were developed, under effect of the tectonic load, in the North and South of the Tianshan Mountains. There were differences along the trend of the intra-continent subduction orogenic belt, in terms of the thickness of crust, the elevation of mountains, the intensity of earthquake etc, between eastern and western Tianshan Mountains. It was clear that the West of Tianshan Mountains was more active than the East. The Bogeda Mountains showed the intensive activity in the formation of intra-continent orogenic belt. Lift and thrust-fold belt, formed in the stage, controlled the deposition in the foreland basins developed in the two sides of the Mountains. There was comparison between the West of the Tianshan Mountains and Bogeda Mountains. All of them showed that there was a transfer zone, which transferred the shortening from the West of the Tianshan Mountains to the Bogeda Mountains, in the development of intra-continent orogenic belt. The difference of the crust shortening of western and eastern Tianshan Mountains was transferred to the Bogeda Mountains. The transfer zone balanced the differences between eastern and western Tianshan Mountains, and named as Urumqi-Kuerle transfer zone.