Structural Characteristics,formation And Evolution Of The Eastern Part Of The Southern Margin In The Junggar Basin

The eastern part of the southern margin of the Junggar Basin is mainly located in the Bogeda Mountain area to the east of Urumqi.It mainly includes Fukang fault zone,the Beisantai bulge,and the Jimsar sag where is an important hydrocarbon-bearing zone in the Junggar Basin.By 2D and 3D seismic data and logging data,and on the premise of defining regional tectonic evolution history,the structural characteristics,structural styles,genetic mechanism and evolution of outcrop and overburden areas in the study area are studied in depth.Through this study,it is concluded that the eastern part of the southern margin of Junggar Basin mainly develops fault-fold belts which are nearly parallel in plane and protrude northward,and thrust faults with imbricate distribution are steep and gentle in profile.From south to north is the Bogda North Fault,the Yaomoshan Fault,the Dahuangshan South Fault,the Dahuangshan North Fault,and the Fukang Fault.It is a fore-expanding fault formed under the compressive stress from south to north.Among them,the Bogeda North Fault,the Yaomoshan Fault and the Fukang Fault have large scale,long extension and branch fault development.The main folds from south to north are the Quanshuigou syncline,the Quanshuigou anticline,the Huangshan syncline,the Huangshan anticline,the Huangshan northward slope,the Huangshanbei anticline,and the Dahuangshan-Second River.The Yaomoshan Fault controlled the development of the spring ditch and the anticline.The southern fault of the Dahuangshan controlled the development of the Huangshan syncline and the anticline.The northern fault of the Dahuangshan controlled the development of the northward slope of the Huangshan Mountain and the north anticline of the Huangshan.The fault controlled the development of the Dahuangshan-Ergonghe syncline.Through field survey,seismic interpretation and tectonic physics simulation of typical geological sections: the planar shape of the northward protrusion of the Piedmont fault-fold belt in the eastern margin of the southern margin of the Junggar Basin is mainly affected by the strong central and weak stresses on both sides,the stress released due to the development of the fracture,resulting in a gradual increase in the width between the pleat belts and a decrease in the degree of deformation.The fold structure in the eastern part of the southern margin of the Junggar Basin is mostly steep.The rear wing has a slow fault propagation wrinkle,and the wrinkles become more and more tight with the depth.In the initial stage of the fold formation,the fault does not break through the fold but forms a fault propagation wrinkle on the upper disc.As the extrusion distance increases,The fault cuts through the slanting or anticline of the fold,forming different shapes of folds;the eastern section of the southern margin of the Junggar Basin,especially the gap between the Baiyang River section and the Ergong River section,is mainly affected by the thickness of the regional stratum and The influence of tectonic exercise period.