辽东湾JZ27-33区块伸展型右行走滑双重构造系统

The extensional dextral strike-slip duplex of JZ27-33 Block in Liaodong Bay

辽东湾JZ27-33区块发育3条大型NNE向走滑断裂,分别为辽中3号断裂(或者辽中1号断裂)、辽中2号断裂和辽东2号断裂,在平面上,3条走滑断裂呈"雁行式"展布,其间密集发育具有走滑性质的正断层,这些正断层在平面上成NE或者NEE走向,与主走滑断裂斜交,其锐角的指向为本盘地层在平面上的位移方向;在横剖面上,负花状构造是研究区内的大型走滑断裂在横剖面上的重要特征,综合分析认为,研究区的断裂特征在平面上表现为"双重构造"特征,在横剖面上表现为(负)花状构造,构成了典型的"伸展型右旋走滑双重构造"系统,并且认为,形成这种构造样式的控制因素主要有:郯庐断裂带的右旋走滑作用、平面展布特征、多期构造活动以及能干性特征明显的沉积地层。

Three main NNE-striking strike-slip faults are developed in JZ27-33 block of Liaodong Bay,i.e.,Liaozhong 3 fault（or Liaozhong 1 fault）,Liaozhong 2 fault and Liaodong 2 fault.These 3 faults assume en echelon distribution on the plane,with many secondary normal faults of strike-slipping nature developed between them.These normal faults strike NE or NEE and obliquely intersect main strike-slip faults,and the sharp angle between them indicates the corresponding stratigraphic moving direction on the plane.Negative flower structure is another important feature of the giant strike-slip faults.It is therefore concluded that the faults of the study area have characteristics of ＂duplex＂ on the plane and negative flower structure on the cross-section,and that the faults in JZ27-33 block of Liaodong Bay formed a typical ＂extensional dextral strike-slip duplex system＂,with the main controlling factors composed of the dextral strike-slip and plane distribution of Tanlu fault,the multi-phase tectonic movement and the brittle sedimentary layers.