斜滑断层的成因及其沉积响应——以渤海湾盆地济阳坳陷为例

Mechanism and sedimentary responses of oblique faults: A case study of Jiyang Depression, Bohai Bay Basin

李理 赵利 董大伟

LI Li ZHAO Li DONG Dawei

中国石油大学(华东) 地球科学与技术学院, 山东 青岛 266580 2. 海洋国家实验室 海洋矿产资源评价与探测技术功能实验室, 山东 青岛 266071 3. 山东农业大学 资源与环境学院, 山东 泰安 271018 4. 中国石油大学(华东) 胜利学院, 山东 东营 257061

School of Geosciences, China University of Petroleum, Qingdao, Shandong 266580, China 2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266071, China 3. College of Resources and Environment, Shandong Agriculture University, Tai'an, Shandong 271018, China 4. Shengli Institute, China University of Petroleum, Dongying, Shandong 257061, China

斜滑断层是一种重要的构造变形，断层的斜向滑动导致盆地发生斜向裂陷作用，并在一定程度上控制着盆地内的沉积体系。在系统分析斜滑断层的变形机制的基础上，将斜滑断层的成因分为4类，即：同期纯剪切、简单剪切和一般剪切，以及由斜向伸展/挤压导致的多期纯剪应变。通过对济阳坳陷三维地震资料解释及其内断层的平面、剖面解析以及运动学参数计算，结合区域构造演化，得出济阳坳陷中生代以来斜滑断层的活动特征。印支期受区域挤压应力场作用断层为逆斜滑活动，燕山期受区域简单剪切作用为正斜滑活动，喜马拉雅期受区域伸展应力场作用主要是正斜滑活动；同时，还包括一般剪切作用下的正斜滑活动及由于应力场转换产生的继承性斜向伸展。斜滑断层的活动控制着盆地边缘扇体的横向迁移和叠置、碎屑体系的推进和展布，空间上解析了由沉积体横向叠置产生的沉积叠瓦、斜歪背斜等地质现象。利用沉积体展布来判断斜滑断层旋向时可能会出现一些假象，需要结合断层的次级构造或区域构造演化史进行判断。

Oblique faults played an important role in the structural deformation of superimposed basins, which resulted in oblique rifting and controlled the sedimentary system in some ways. The systematic mechanism analyses showed that three contemporaneous deformations and one multiphase deformation controlled the generation of oblique faults, including contemporaneous pure shear, simple shear, general shear, and multiphase pure shear by oblique extension/compression. The activity features of oblique faults in the Jiyang Depression ever since Mesozoic were determined on the basis of 3D seismic data interpretation, plane and section analyses of fault and kinematic parameter calculations, combined with regional tectonic evolution. The oblique faults showed reverse oblique-slip in the Indosinian compressional stress field, normal oblique-slip in the Yanshanian simple shear, and normal oblique-slip in the Himalayan extensional stress field. In addition, there were also some normal oblique-slip faults under general shear and inherited oblique-slip faults under oblique extension by stress field transformation. The activities of oblique-slip faults controlled the lateral migration and stacking of fan bodies at the margin of the basin and the dispersion and spreading of sedimentary systems. As the sedimentary response to oblique-slip, the sedimentary imbricates and inclined anticlines formed by the oblique faults' strike slipping in three dimensions were dissected. Several false appearances in judging the faults' slip direction by sedimentary fan body were discussed, which demand intensive studies on secondary structures or regional tectonic evolution.

国家自然科学基金（41672193）资助。

https://doi.org/10.11781/sysydz201802149