天山北麓晚新生代独山子-安集海褶皱冲断带构造分析及其对河流改道的影响

新生代以来，受印度极块与欧亚大陆的碰撞和持续汇聚作用的影响，天山强烈变形隆升，并在南北两侧形成了一系列冲断推覆构造．大山北缘由南向北发育了3排褶皱-冲断带，第三排独山子-安集海构造形成于第四纪以来．根据野外地表考察结果并利用二维反射地震剖面资料，定量分析了独山子背斜和安集海背斜的构造几何学和运动学特征，确定了他们的变形时间和变形量．独山子背斜和安集海背斜的最小缩短量分别为4340m和l240m，缩短率分别为15．74％和7．2％，由于构造降升幅度的差异，造成了发育于北天山山前的一系列河流发生横向迁移，奎屯河和安集海河偏流向东发生河流改道．

STRUCTURAL ANALYSIS OF THE DUSHANZI-ANJIHAI LATE CENOZOIC FOLD-THRUST BELT AND IT'S INFLUENCE ON RIVER CHANNELS, NORTH TIANSHAN

Since the Cenozoic, the Tianshan deformed and uplifted intensively as a result of the Indian Plate collided with Eurasian continent. There come into being a series of thrust belts in both southern and northern sides of Tianshan consequently. There have developed three fold-thrust belts from the north side of Tianshan in which the third row of Dushanzi-Anjihai anticline formed during Quaternary. Based on field geological exploration together with the 2D seismic reflection profiles, we analyzed quantificationally the geometry and kinematics of Dushanzi and Anjihai anticline, confirmed the timing and the quantity of deformation. The tectonic shortening amount of Dushanzi anticline was 4340m and its shortening rate was 15.74%, while the tectonic shortening amount of Anjihai anticline was 1240m and the tectonic shortening rate was 7.2%. Due to the difference of uplifting extent, a series of rivers in north Tianshan changed their channels eastward .Both Kuntun River and Anjihai River changed the channels and flowed to the east.