塔里木盆地孔雀河斜坡维马克背斜构造的构造特征与形成演化

维马克背斜构造带位于孔雀河斜坡的东部,该背斜构造带西段发育北西走向断裂,东段发育北东东走向断裂,是孔雀河斜坡两大断裂系统的构造转换地带,解析该背斜构造带的构造特征对于认识孔雀河斜坡成因演化和塔里木盆地东北缘早古生代以来的地球动力学背景都具有重要的意义。本文利用断层相关褶皱理论,通过对过孔雀河斜坡维马克背斜构造带地震剖面的精细解释,分析了该背斜构造的构造特征并讨论了其形成演化。维马克背斜构造带西段受北西走向的断裂组F_w1 和F_w2 控制,维马克1号背斜呈北西-南东向展布,东段受北东东走向的断裂组F_w3 和F_w4 控制,维马克2号背斜呈北东-南西向展布,维马克背斜卷入变形的地层为中-上奥陶统、志留系、侏罗系和白垩系,控制背斜形态的断裂系统具有挤压扭动的动力学特征,维马克背斜构造带及其南北两侧盆山系统构造演化大致经历了5期构造运动,维马克背斜构造带至库鲁克塔格山前带地壳缩短37.4 km,南段英吉苏凹陷南缘斜坡带缩短4.31 km,缩短率为25.32%。研究认为,维马克背斜断裂系统是北西向和北东东向两大断裂系统相互影响下的特定构造样式,来自南北不同方向的构造应力在维马克背斜构造带产生走滑效应,使得维马克背斜构造断裂系统具有挤压扭动的特征。

Tectonic features, formation and evolution of Weimake anticline-structure of Kongquehe Slope, Tarim Basin

Weimake anticline-structure zone,whose west part developed NW striking faults and east part developed NEE striking faults,located in the eastern part of Kongquehe Slope,is the structural transferring zone of the two faults system of Kongquehe Slope.The interpretation and analysis of the anticline structure is very important to recognize the formation and evolution of Kongquehe Slope and to reveal the geodynamic settings of the northeastern margin of Tarim Basin since Early Paleozoic. Through the fine interpretation of the seismic profile across Weimake anticline-structural zone,using the theory of fault-related fold,this paper analyzed the tectonic features and the formation and evolution of the anticline structure.Weimake 1^st anticline,which is NW-SE direction spreading,is controlled by the NW striking faults F_w1 and F_w2,the west part of Weimake anticline-structure zone; Weimake 2^nd anticline,which is NE-SW direction spreading,is controlled by the NEE striking faults F_w3 and F_w4,the east part of Weimake anticline-structure zone; the deformation strata of the anticline whose faults system are the asymmetric positive flower structure having dynamics characteristics of extrusion and wreathe,are the middle-upper Ordovician,the Silurian,the Jurassic and the Cretaceous.The structure evolution of Weimake anticline-structure and its periphery area have five stages.The crustal shortening of the belt between Weimake anticline-structure zone and the Quruqtagh Mountain front is 37.4 km,the crustal shortening of the south slope of Yingjisu Sag is 4.31 km,the shortening rate is 25.32%。This research thinks the positive flower structure of Weimake anticline faults system,is the result of the interaction of NW striking and NEE striking faults system.The structure stress from south and north generate strike-slip effect in Weimake anticline-structure zone,made the Weimake anticline fault system have the characteristics of extrusion and wrench movement.