摘要
珠江口盆地是南海北部陆缘新生代发育的裂陷型盆地,其油气资源丰富,且地处洋陆过渡带,盆地内部断裂特征复杂.在前人研究基础上,利用高分辨率三维地震数据,结合多属性分析技术,完善了区域断裂的精细化解释.将断裂构造类型依据断裂级别与规模划分为控盆一级断裂、控凹二级断裂、控带三级断裂、控圈四级断裂和控层五级小断裂;在盆地西南段发育典型的犁式、旋转正断层等单剖面断裂样式,在地震剖面上形成阶梯状、"Y"字型等多种断层组合,其中珠三坳陷的文昌A凹陷内部常可见树枝状构造,珠二坳陷的开平凹陷广泛分布独特的卷心式断层;而在二维平面上也分布有平行式、斜交式、雁列式等多种组合类型.受新生代以来的持续右旋应力场作用,盆地西南段整体断裂走向以NE→EW→NW顺时针方向发生旋转,且断裂活动速率逐渐降低.结果表明受印度-欧亚板块碰撞、太平洋板块俯冲后撤和古南海持续南移的联合影响,盆地西南段处在伸展拉张应力场环境之下,形成了始新世-渐新世NE-NEE向、EW向和中新世NWW-NW向3组断裂发育.珠江口盆地西南段断裂构造的演化、成因机制与南海北部陆缘应力场变化均保持良好的一致性.
The Pearl River Mouth basin is a rift basin developed in the Cenozoic on the continental margin of the northern South China Sea, which is located in the ocean-continent transition zone with rich oil and gas resources. It is very important to analyze the internal fracture characteristics of the Pearl River Mouth basin. Based on previous studies, this paper uses three-dimensional highresolution seismic data, combined with the application of coherent attribute analysis technology to refine the interpretation of regional faults. The faults are classified into the first-level basin-controlling faults, the second-level sag-controlling faults, the thirdlevel belt-controlling faults, and the fourth-level ring-controlling faults in the area based on the level and scale of the faults. Singlesection fault styles such as normal faults, form step-shaped,"Y"-shaped and other fault combinations on the seismic section.Among them, negative flower-like structures present in the Wenchang A sag in the Zhusan sag and unique core-shaped faults are widely distributed in the Kaiping depression of the Zhuer sag. During the Late Oligocene-Early Miocene, the fault direction rotated clockwise from NE→EW→NWW under the continuous right-handed stress field since the Cenozoic, and the activity intensity gradually weakened. It is also believed that affected by the collision of the India-Eurasia Plate, the subduction and retreat of the Pacific Plate and the continuous southward movement of the Paleo-South China Sea, the basin formed a typical extensional tensile stress field environment, which contributed to the development of three fault groups in NE-NEE and EW direction during the Eocene-Oligocene, and in the NWW-NW direction in Miocene. Moreover, the evolution and genetic mechanism of the fault structure in the southwestern part of the Pearl River Mouth basin are in good agreement with the changes in the stress field at the northern margin of the South China Sea.
作者
王嘉
栾锡武
何兵寿
冉伟民
张豪
杨佳佳
Wang Jia;Luan Xiwu;He Bingshou;Ran Weimin;Zhang Hao;Yang Jiajia(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 266237,China;School of Geosciences,China University of Petroleum,Qingdao 266580,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2021年第3期916-928,共13页
Earth Science
基金
国家基金重大研究计划项目(No.92055211)
中国-东盟海上合作基金项目(No.12120100500017001)。
关键词
珠江口盆地西南段
断裂走向
断层活动速率
应力场环境
海洋地质
southwest section of Pearl River Mouth basin
fracture trend
fault activity rate
stress field environment
marine geology
