Structure Characteristics,Formation And Evolution Of The Zhongguai Uplift

The Zhongguai uplift is a nose dumping southeast,which is located in the transition zone of the Ke-Bai fault zone and Hong-Che fault zone,in the northwest margin of the Junggar Basin.Affected by strong tectonics,the protrusions have complex structural features.In this paper,through the fine interpretation of the re-processed high-density three-dimensional(3D)seismic data,combined with the latest exploratory data and field reconnaissance,the paper analyzes the structural characteristics,fault system,formation and evolution of the Zhongguai uplift rom a new perspective,and achieved important results and understanding.The Zhongguai area has experienced Hercynian,Indosinian,Yanshan and Himalayan tectonic cycle etc,and developed 4 categories,12 kinds of structural style.The compression structural style developed in deep(Permo-Carboniferous);the strike-slip structural style developed in middle(Triaasic-Jurassic);and extensional structural style developed in shallow(Cretaceous and above).Based on the interpretation of 3D seismic data,it was found that the thrust faults,normal faults and strike-slip faults all developed in the Zhongguai uplift and the distribution regularity is obvious.Four large-sacle strike-slip faults were found in the Zhongguai uplift,respectively,which are the Hong 3 Well East strike-slip fault,the Guai 6 Well strike-slip fault,the 598 Well strike-slip fault and the well of the 598 Well East strike-slip fault.The formation of these strike-slip faults was related to the Indosinian left-lateral strike-slip of the Dahlute fault.In the multi-period tectonic movement,a variety of fracture assemblage patterns were presented on the cross-section of each tectonic area.There were thrust-type combinations and "Y"-shaped combinations(consists of the fault faults),the flower-like structure(consists of the strike-slip faults),Graben-horst combination and step-like combination,and a special "Y"-like shape combination of patterns(consists of the deep reverse fault and the upper normal fault.According to the characteristics,size,cutted horizon of fault,combined with the fault activity period,the faults were divided into three major fault systems in the base of Triassic bottom and the Cretaceous bottom,namely,deep-layer squeeze thrust Fault system,middle-layer torsional strike-slip fault system,shallow-layer extensional normal fault system.The deep-layer fault system dominateed,constructed the structual framework and has an important effect on the activity of the middle-shallow faults.The strike-slip period in the middle-layer was an important turning point,the uplift finalized at late strike-slip fault activity period.Under the influence of the multi-period differential stress of the surrounding plate,the formation and evolution of the Zhongguai uplift is controlled by the multi-period compression uplift of the Zaire Mountains and the multi-period strike slip movement of the Daerbute fault,which can be divided into four evolution stages:the basement uplift stage from late Carboniferous to early Jiamuhe period,the severe faulting-uplift stage from middle Jiamuhe period to late Permian,the slow transpressional uplift stage from Triassic to Jurassic,the recessive burial stage from Cretaceous to Neogene.