准噶尔盆地中拐凸起断裂体系特征及形成演化

摘要

Zhongguai uplift in Junggar Basin experiences multi stages of tectonic movements.The superimposition and alteration mineralization of faults are strong,forming complex fault systems. According to the new collected high-precision 3D seismic data,the fault systems in Zhongguai uplift were interpreted,and the superimposed relation of different fault systems identified was discussed.The results show that the faults in Zhongguai uplift can be divided into thrust fault, normal fault and strike-slip fault,which have significant differences;according to the types, scale,activity and formation mechanism of these faults,the fault systems in Zhongguai uplift include Carboniferous-Permian compression and thrust fault system,Triassic-Jurassic transpressive and strike-slip fault system and Cretaceous-Neogene extensive normal fault system;according to the difference of fault occurrence,corresponding relation of faults in plane and in profile,and genetic relationship with boundary fault,the faults in plane can be subdivided into the thrust-slip fault group in the east of well Hong3,the thrust-slip fault group in the east of well 598,the thrust-slip fault group in the east of Hongshanzui,the thrust fault group in the south of Wuqu,the thrust-weak slip fault group in Karamay,and the thrust-slip fault group in the east of well Guai6;the structure and combination of each fault group are unique individually;according to the tectonic evolution setting in the northwestern margin of Junggar Basin,combined with balance section restoration, the fault systems in Zhongguai uplift can be divided into Permian compression and thrust stage, Triassic-Jurassic transpressive stage and Cretaceous-Neogene tilted extensive stage.%准噶尔盆地中拐凸起经历了多期构造运动,断裂叠加改造作用强烈,断裂关系极为复杂.利用最新采集的高精度三维地震资料,对中拐凸起发育的断裂进行了精细解析,识别出逆断裂、正断裂、走滑断裂等多种性质的断裂,它们发育具有明显差异性.剖面上,以三叠系底和白垩系底为界,将中拐凸起断裂划分为深层石炭系—二叠系挤压逆冲断裂体系、中层三叠系—侏罗系压扭走滑断裂体系和浅层白垩系—新近系伸展正断裂体系,并分析了不同断裂体系的叠加关系.平面上,将中拐凸起发育的断裂划分为红3井东逆冲-走滑断裂系统、598井东逆冲-走滑断裂系统、红山嘴东逆冲-走滑断裂系统、五区南逆冲断裂系统、克拉玛依逆冲-弱走滑断裂系统和拐6井走滑断裂系统,它们各自具有独特的构造与组合特征.根据准噶尔盆地西北缘构造演化背景,结合平衡剖面恢复,将中拐凸起断裂体系划分为二叠纪挤压逆冲阶段、三叠纪—侏罗纪压扭走滑阶段和白垩纪—新近纪掀斜伸展阶段.