塔里木盆地阿图什—八盘水磨反冲构造系统研究

通过大量野外地质调查和深部物探（地震剖面、MT和重力）综合构造解释，在位于东起八盘水磨，西对乌鲁克恰特以西的南天山前陆冲断带中，确定了阿图什－八盘水磨反冲构造系统及其三角带构造；该反冲系统由小阿图什－八盘水磨和乌尔－喀拉套山反冲构造系统及小阿图什－乌鲁克恰特被变形的反冲构造系统组成；即在以往认为南天山向塔里木盆地大规模中推覆的地区，塔里木盆地美国层第四纪以来沿多组滑脱面向天山新生代造山带反冲推覆。塔里木盆地反冲构造系统发育的区域基底埋深往往大于10km，对应麦盖提基底构造下凹区，而相邻柯坪塔格薄皮推覆构造系统发育的区域基底埋深一般小于10km,对应巴楚基底构造上隆区；逆冲和反冲构造转换带基底埋深约10km,平衡剖面恢复表明弧形逆冲和反冲构造顶部分别为逆冲和反冲位移量最大位置。

A STUDY ON THE BACK-THRUSTING SYSTEM AT ATUSHI-BAPANSHUIMO IN TARIM BASIN

Through field geological investigation and integrated interpretation of geophysical exploration data (seismic reflection profiles, MT and gravity data), we have defined the back-thrusting systems of Atushi-Bapanshuimo and their triangle zones in southwest Tarim basin, which are located along the foreland belts of southern Tienshan from the east of Bapanshuimo to the west of Ulukqiate. The back-thrusting systems consist of sub-Tarim basin back-thrusting systems of Xiao Atushi-Bapanshuimo, Uer-Kalataoshan and deformed Tarim Basin back-thrusting systems of Xiao Atushi- Ulukqiate. It is suggested that the back-thrusting systems formed along the multi-thrusting faults in Quaternary in the foreland belts of southern Tienshan where the southwest Tieshan orogenic belts thrust to the Tarim basin. The Tarim basin back-thrusting systems formed in the area where the thickness of sedimentary covers is greater than 10km, which corresponds to the depression of the basement (Maigaiti slope) and the adjacent Kalpintage thin-skinned thrusting systems formed in the area where the thickness of sedimentary covers is less than 10km, which corresponds to the uplift of the basement (Bachu basement uplift). The depth of basement in the transitional zones between the thrusting system of Kalpintage foreland belts and back-thrusting system of Tarim basin is about 10km. The balanced cross-sections show that the top of the convex of tectonic arc in thrusting and back thrusting systems has the largest displacement.