济阳坳陷东部长堤走滑断裂带构造特征及演化过程

Characters of Changdi fault in the east of Jiyang depression and its reconstruction process

济阳坳陷东部长堤断裂是一条特征明显的走滑断裂带,以T2地震反射层（沙河街组二段底面反射层）为界,发育深层次和浅层次两套断裂系统.深层次断裂系统为长堤走滑断裂带的主体,发育R-P断层组合,剖面上呈丝带状构造样式,平面上呈发辫状构造样式;浅层次断裂系统由一组近南北向左阶羽状雁列带组成,雁列带中的每条断层为近南北向走滑断裂的T断层.Es3-Es2下期,长堤走滑断裂带开始活动,发育深层次断裂系统,系由济阳坳陷和渤中坳陷之间的构造调节作用所造成;Es2上-Ed期,发育浅层次断裂系统,与长堤深层次断裂持续活动以及沉积盖层的逐渐增厚有关,同时,郯庐断裂带开始对研究区的构造格局产生影响;Ng-Nm期,研究区处在巨大的北东向走滑递进应变带中,长堤近南北向走滑断裂带让位于郯庐断裂带控制的北东向走滑体系.

Changdi fault is a representative strike-slip fault zone in the east of Jiyang depression,which included deep and shallow fault systems.The deep fault system which developed R-P faults is the main body of Changdi fault.The deep fault system manifested ribbon structural style in cross section and pigtail structural style in plane.The shallow fault system was consisted of NS-trending left-order en-echelon faults.Each fault in the en-echelon faults zone was NS-trending T-fault of strike-slip fault.The development history of Changdi fault could divide into three stages including the deposition periods during Member 3 of Shahejie Formation to Lower Member 2 of Shahejie Formation,Upper Member 2 of Shahejie Formation to Dongying Formation and Guantao Formation to Minghuazhen Formation.Because of the accommodate effect between Jiyang and Bozhong depression,Changdi fault started activities and developed deep fault system at the deposition period during Member 3 of Shahejie Formation to Lower Member 2 of Shahejie Formation.Affected by gradually thickened sedimentary cover and continuing activities of deep fault system,the shallow fault system of Changdi fault started activities at the deposition period during Upper Member 2 of Shahejie Formation to Dongying Formation.At the same time,Tanlu fault began to affect the structural pattern in study area,the activity of the fault in left-order en-echelon faults zone was enhanced and a large-scale north-trending fault zone was formed.The shallow fault system was increasingly apparent at the deposition period during Guantao Formation to Minghuazhen Formation.The NS-trending strikeslip fault gave way to the NE-trending strike-slip fault which controlled by Tanlu fault.