摘要
珠江口盆地作为南海北部陆缘勘探程度较高的含油气盆地,断裂特征分析对认识盆地演化模式和油气成藏机理至关重要。根据高分辨率地震数据和钻井资料对盆地西南部开平凹陷进行精细地震地质解释,依据断裂级别与规模将该区断裂构造类型划分为一级控盆断裂、二级控凹断裂、三级控带断裂以及四级控圈断裂;在地震剖面上识别出“Y”字型断层、阶梯状断层及卷心型断层等多种剖面组合样式;根据断裂平面分布图识别出平行式、雁列式、斜交式3种平面组合类型;定量统计断裂走向特征可知,在右旋应力场作用下,自始新世到早中新世断裂走向持续发生近NE→EW→近NW向的顺时针旋转,且断裂活动性逐渐减弱。并认为受印度‒欧亚板块碰撞、太平洋板块俯冲后撤和古南海持续南移的影响,盆地形成典型的伸展拉张应力场环境,促成始新世‒渐新世期间近NE向、EW向和中新世期间发育的近NW向3组断裂发育。对开平凹陷的地质构造特征加以解释补充,为南海北缘洋陆过渡带的发育特性和成因机制提供参考。
The Zhujiang River Mouth Basin is a petroleum-bearing basin with a high degree of exploration in the northern continental margin of the South China Sea,the analysis of fault characteristics is crucial to its basin evolution model and hydrocarbon accumulation mechanism.According to the high-resolution seismic data and drilling data,the fine seismic geological interpretation of the Kaiping Sag in the southwest of the basin is carried out.Based on the fault grade and scale,the fault structure type is divided into the first-level basin-controlled fault,the second-level sag-controlled fault and the third-level control fault based on the level and scale of faults belt fracture and four-level control ring fracture,identify“Y”shaped faults,stepped faults,and heart-shaped faults combination styles on the seismic section,identify three plane combinations of parallel,goose,and oblique based on the fault plane distribution Types of quantitative statistics of the fault strike characteristics show that under the action of the right-handed stress field,from the Eocene to the Early Miocene,the strike direction continued to rotate clockwise in the direction of NE→EW→NW,and the fracture activity gradually weakened.It is also believed that due to the impact of the Indian-Eurasian plate collision,the subduction and retreat of the Pacific plate and the continuous southward movement of the ancient South China Sea,the Zhujiang River Mouth Basin formes a typical extensional tensile stress field environment.It contributes to the development of three groups of faults in the near NE direction,the EW direction and the near-NW direction during the Eocene-Oligocene period.It provides an explanation and supplement to the geological structural characteristics of Kaiping Sag,and provides a reference for the development characteristics and genetic mechanism of the ocean-continent transition zone on the northern margin of the South China Sea.
作者
王嘉
栾锡武
何兵寿
冉伟民
魏新元
胡庆
韦明盟
龚梁轩
Wang Jia;Luan Xiwu;He Bingshou;Ran Weimin;Wei Xingyuan;Hu Qing;Wei Mingmeng;Gong Liangxuan(College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;Qingdao Institute of Marine Geology,China Geological Survey,Qingdao 266071,China;Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China;College of Marine Science and Technology,China University of Geosciences,Wuhan 430074,China)
出处
《海洋学报》
CAS
CSCD
北大核心
2021年第8期41-53,共13页
基金
中国东盟海洋地震数据平台建设基金(12120100500017001)
国家自然科学基金(42006067,92055211,41674118)
青岛海洋科学与技术试点国家实验室基金(QNLM201708)
国家重点研发计划(2018YFC1405900)。
关键词
开平凹陷
断裂走向
断裂活动性
应力场环境
成因机制
Kaiping Sag
fault strike
faulting activity
stress field environment
formation mechanism
