Superposed relationship between Kalping thrust belt and Bachu uplift,northwest Tarim

The Kalping thrust belt,northwest Tarim,is an actively deformed district affected by the Indian-Eurasia collision originated from the coupling between the Tianshan and Tarim basins in Cenozoic Era.Overall verges in the Kalping thrust belt are toward the interior of the Tarim basin,from the Tianshan to the south.Styles of structural deformation are composed of large thin-skinned structures with its decollement horizon of Cambrian evaporates,and thrust faults involved in the Precambrian-Proterozoic crystalline basement,as well as NW-strike-slip faults.The thrust belt can be divided by the Piqiang strike-slip fault,the Yingan strike-slip fault into three regions,i.e.the Xiker region,the Kalping region and the Akesu region,according to the variation and differentiation of structural deformation styles of the Kalping thrust belt.In the Xiker region,much great thickness of strata were involved in the Kalpin thrust belt and the depth of basement decollement horizon is 7～8 km.Relatively little thickness of strata were involved in the Kalpin thrust belt in the Kalping region and the depth of basement decollement horizon is 5～6 km.In the Akesu region,the Precambrian basement was involved in the Kalping thrust belt.Differences of structural styles result from the superposition of NW-striking Bachu uplift with the NE-striking Kalping thrust belt,especially the superposition of the high-angle Piqiang thrust fault at the southern boundary of the Bachu uplift with the counterclockwise Piqiang strike-slip fault,and of the high-angle Yingan(Aqia or Tumuxiuke)thrust fault at the northern edge of the Bachu uplift with the clockwise Yingan strike-slip fault.