苏北盆地高邮凹陷基底先存断裂成因及其对新生断裂的控制

Origin of pre-existing basement faults and their controls on new fault formation in Gaoyou Sag, Subei Basin

束宁凯 吴林 汪新文 郭建平

Shu Ningkai Wu Lin Wang Xinwen Guo Jianping

中国地质大学(北京) 地球科学与资源学院, 北京 100083 2. 中国石油勘探开发研究院, 北京 100083

School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China 2. Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China

真武断裂和吴堡断裂是苏北盆地高邮凹陷的2条重要基底先存断裂，形成于印支期下扬子板块与华北板块的俯冲碰撞，西部走向北东东、东部走向北北东。根据区域应力场、三维地震等资料，将这2条基底断裂对南部断阶带形成和演化的控制作用分为4个阶段：（1）构造挤压期，由于下扬子区北部与华北板块东南部的碰撞，形成了一系列的冲断构造、逆冲推覆及褶皱变形；（2）构造反转期，真武断裂由逆断层反转为正断层；（3）正向裂陷期，真①断层、吴①断层继承了真武断裂分段性特点，真武断阶带、吴堡断阶带分别受真①断层、吴①断层控制强烈；（4）斜向裂陷期，真武断阶带、吴堡断阶带受基底断裂控制作用逐渐减弱，南北向张应力起主导作用。真武断阶带和吴堡断阶带存在着构造差异变形，根据基底先存断裂对新生断裂的活动方式可分为4种类型，由强至弱依次分为继承型、派生型、调节型、诱导型。研究表明，基底先存断裂是高邮凹陷南部断阶带形成演化的基础，并强烈影响着新生断裂的发育。

The Zhenwu and Wubu faults are two major pre-existing basement faults in the Gaoyou Sag, Subei Basin. They were formed during the Indosinian period when the Lower Yangtze plate collided with the North China plate, and strike NEE in the west and NNE in the east. The regional stress field and 3D seismic data showed that the controls of the two faults on the development of the southern terrace can be divided into four periods as follows. (1) Tectonic compression. The north of the Lower Yangtze plate collided with the southeast of the North China plate, developing a series of thrust slip, thrust-motion and complicated dislocation. (2) Tectonic reverse. The Zhenwu fault reversed from a normal fault to a reverse fault. (3) Orthogonal rifting. The Zhenwu fault diffe-rentiated into the Zhen① and Wu① faults which controlled the formation of Zhenwu and Wubu terraces. (4) Oblique rifting. The Zhenwu and Wubu terraces were controlled by NS oriented extensional environment instead of the Zhenwu fault. Tectonic deformations were different in the Zhenwu and Wubu terraces. According to the activity of pre-existing basement faults in new faults, they were classified into four types from strong to weak in turn: inherited, variable, adjusted, and induced. Pre-existing basement faults were the foundation of the southern terrace formation and evolution, and strongly influenced the development of new faults.

国家科技重大专项（2011ZX05028，2011ZX05009-002）资助。

https://doi.org/10.11781/sysydz201701008