【摘要】 受多期次构造应力场叠加转变的影响,迈陈凹陷东部断裂发育具有明显的阶段性,平面上断裂走向在古新统和始新统以NE向为主,渐新统转变为EW和NEE向,剖面上以T4反射层(涠州组底)为界可以划分为上下两套断裂系统,上下两套断裂系统继承与改造并存。针对这一问题,在地震、钻井岩心和区域地质背景资料分析解释的基础上,对迈陈凹陷东部断裂系统的发育演化进行构造物理模拟实验正演分析。实验结果表明:迈陈凹陷东部在古新世—中始新世主要受控于NW向伸展应力场,以NE向断裂发育为主;晚始新世在NW向拉张的同时叠加了右旋剪切作用,近EW向断裂开始发育,部分早期发育的NE向断裂继承性活动。更多还原

【Abstract】 Influenced by the superimposition and transformation of multiple phrases of tectonic stress field,the development of the eastern fault system displays apparent periodicity in Maichen sag. On the plane view,the fault strike was mainly NE trending in Paleocene and Eocene,and changed to EW and NEE in Oligocene. On the seismic section,taking T4 reflecting surface( the bottom boundary of Weizhou Formation) as a boundary,the fault system can be divided into the upper system and the lower system,between which inheritance and transformation coexist. Aiming at this problem,based on the analysis of seismic data,drilling cores,and regional geological background,structure physical simulations were performed to model the eastern fault system’s evolution in Maichen sag. The results show that the eastern area of Maichen sag was mainly controlled by the NW tensional stress from Paleocene to Middle Eocene,and the fault strike was mainly NE trending. In the late Eocene,dextral shearing was superimposed on the NW tensional stress,which contributed to the development of the EW-trending faults,and some of those early developed NW-trending faults act successively.更多还原