Deformation And Activity Characteristics Of Strike Slip Fault Zone In Zhengshacun Area,Junggar Basin

A large number of strike slip faults are developed around Mosuowan uplift in Junggar basin,with many active periods and complex deformation characteristics,which have an important impact on oil and gas accumulation.In the multi-stage evolution process,the strike slip fault has been continuously transformed,resulting in unclear understanding of its geometric and kinematic characteristics,different time division of fault activity and unclear formation mechanism.Taking the zhengshacun area on the western edge of Mosuowan uplift as the research object,through the fine interpretation of 3D seismic data and coherent body plane analysis,this paper makes a geometric and kinematic analysis of the strike slip fault,establishes the profile and plane identification standard of the strike slip fault,and defines the structural characteristics,evolution period and formation mechanism of the zhengshacun strike slip fault.It is found that three sets of deep,medium and shallow structural layers are developed in zhengshacun area,different structural layers are deformed differently,and the faults are superimposed longitudinally,forming three structural styles of "flower","Y" shape and high steep vertical linear shape,.Two groups of strike slip fault systems near we and Sn are formed on the plane.The strike slip fault in zhengshacun area has experienced three stages of structural evolution.The deep structural layer in stage I formed a near Sn strike slip fault system in the Late Permian,and the profile is negative flower shaped.We trending strike slip faults developed in the middle structural layer of phase II in the early Jurassic,cutting the deep structural layer near Sn trending faults,and the profile formed a positive flower shape.A few near we trending faults were inherited and developed in the middle and late Jurassic in the stage III shallow structural layer.There are differences in the direction of fault movement.The near Sn fault of Permian in deep structural layer has dextral movement,and the near EW fault in medium and shallow structural layer has sinistral movement,The formation of zhengshacun strike slip fault is closely related to the rotation of Junggar block,Tianshan extrusion and the activity of peripheral fault zone.The counterclockwise rotation of Junggar block forms Sn trending right-handed fault system of deep structural layer,and Tianshan compressive torsional stress forms we trending left-handed fault system of medium and shallow structural layer.The adjacent Tianshan orogenic belt and the Hongche dextral strike slip fault zone affect the development of the fault and control the structural style and plane distribution of the strike slip fault section.The fault is continuously transformed by multi-stage tectonic movement to form a complex fault system.