库车坳陷区喀桑托开逆断裂-背斜带晚第四纪以来变形特征及活动速率

摘要

Through the inverse fracture cob santo open-anticline belt of field geological investigation,geometric distri-bution of tectonic belt and new achievements of fracturein the late quaternary have been obtained.Research suggests that the Kasangtuokai thrusting fault- anticline is in the north rim of baicheng basin,it consists of kuregeremu- bashjiqike thrusting fault-anticline belt and tuzimazha-kasangtuokai thrusting faults-anticline belt,was a closed linear fold.Kasangtu-okai is a typical Fault extension fold,this kind of structure of the crust shortening is mainly controlled by the anticlinede-velopment evolution on the fracture of plate caused the overall uplift,fold uplift effect is relatively weak,the deformation is mainly focused on the fracture near the anticline belt since late pleistocene crustal shortening rate of about 0.8~1.1 mm/a.Through measuring the ancient earthquake rupture anticline scarp of the southwing of the anticline,obtained 0.3~0.5 m high of the fault scarp formed by earthquake for the last time,thus calculated rupture the vertical displacement rate since the middle holocene is 0.3~0.45 mm/a,shows that the kasangtuokai anticline zone have the tectonic conditions of earthquake in the future.%通过对喀桑托开逆断裂-背斜带的野外地质调查，对构造带的几何展布及断裂的晚第四纪新活动特征取得了新成果。研究认为喀桑托开逆断裂-背斜是拜城盆地北缘近EW向展布的活动逆断裂-背斜带，它由库热格热木-巴什基齐克逆断裂-背斜带和吐孜麻扎-喀桑托开逆断裂-背斜带组成，呈北缓南陡的不对称紧闭线状褶皱。喀桑托开逆断裂-背斜属典型的断层扩展褶皱，此类构造的地壳缩短主要是由控制背斜发展演化的断裂上盘整体抬升引起，褶皱隆起作用相对偏弱，变形量主要集中于断裂附近，背斜带晚更新世以来地壳缩短速率约为0.8~1.1 mm/a。通过对背斜南翼断裂古地震陡坎的测量，获得断层最后一次地震形成的陡坎高0.3~0.5 m，由此计算得到断裂全新世中期以来的垂直位移速率为0.3~0.45 mm/a，表明喀桑托开背斜带未来具备发生强震的构造条件。