琼东南断裂带地质- 地球物理特征及未来科学钻探建议

2022,96(8):2866-2876
朱荣伟1,2, 杜文波1,2, 熊量莉1, 汪俊1, 张伙带1,2, 姚永坚1,2, 蔡观强1
1) 中国地质调查局广州海洋地质调查局，自然资源部海底矿产资源重点实验室，广东广州，510075;2. 2) 南方海洋科学与工程广东省实验室（广州），广东广州，511458
摘要：断裂作为地球内部动力的表层响应对断陷盆地的形成演化有着重要作用，也常成为地震、滑坡等地质灾害的诱发因素。本文基于已有的多道地震资料，对海南岛东南海域的琼东南断裂带的构造特征进行了综合分析。结果表明：琼东南断裂带在平面上大致沿琼东南盆地北侧边界分布，并被一条近EW向断裂错开分成东西两段；该断裂带在新生代初期活动强度较大，约至中新世晚期停止活动，且断裂西段的活动强度明显要大于东段；此外，该断裂带西段在晚始新世至渐新世伴随发育有花状构造，这可能与该时期其西侧的红河断裂正经历快速的左旋走滑活动有关。结合南海北部区域自由空间重力异常特征，推测琼东南断裂带属于滨海断裂带在南海西北部的延伸，而位于海南岛北侧的琼州海峡断裂是莲花山断裂在南海西北部的延伸。基于目前滨海断裂带的研究现状，建议未来开展科学钻探试验时，选择阳江外海域滨海断裂带和琼东南断裂带为钻探靶区，并以钻取断裂两盘和断裂破碎带的岩芯为目的，可为进一步明确滨海断裂带在南海西北部的延伸方向，以及今后更加全面地开展滨海断裂带地震危险性评价提供支撑。
关键词：琼东南断裂带；南海西北部；构造特征；滨海断裂带；科学钻探

Geological- geophysical characteristics of the Qiongdongnan fault zone and future scientific drilling proposals

Zhu Rongwei1,2, Du Wenbo1,2, Xiong Liangli1, Wang Jun1, Zhang Huodai1,2, Yao Yongjian1,2, Cai Guanqiang1
1) Key Laboratory of Marine Mineral Resources, Ministry of Natural Resources, Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou, Guangdong 510075, China;2. 2) Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)，Guangzhou, Guangdong 511458, China
Abstract：As the surface response of the earths internal dynamics, fault play an important role in the formation and evolution of faulted basins, and they often become the inducing factors of geological disasters such as earthquakes and landslides. Based on the existing multi- channel seismic data, the structural characteristics of the Qiongdongnan fault zone on the southeast side of Hainan Island are comprehensively analyzed in this paper. The results show that the Qiongdongnan fault zone is roughly distributed along the northern boundary of the Qiongdongnan basin on the plane, and is disconnected by a EW- trending fault, dividing it into two sections. It was highly active in the Early Cenozoic and ceased activity in the Late Miocene, and the activity intensity of the western fault was significantly greater than that of the eastern segment of the fault. In addition, the western segment of the fault was accompanied by flower- like structures from the Late Eocene to the Oligocene, which may be related to the rapid sinistral strike- slip activity of the Red Rive fault zone in the west during this period. Combined with the characteristics of free air gravity anomalies in the northern part of the South China Sea, it is inferred that the Qiongdongnan fault zone belongs to the extension of the Binhai fault zone in the northwest part of the South China Sea, and the Qiongzhou Strait fault located in the north of Hainan Island should be the extension of the Lianhuashan fault in the northwest part of the South China Sea. Based on the current research status of Binhai fault zone, it is suggested that the Binhai fault zone offshore outside Yangjiang and Qiongdongnan fault zone can be selected as the drilling target area for future scientific drilling experiment, with cores drilled on both sides of the fault and the fracture zone. The drilling results can provide supports for further determining the extension direction of the Binhai fault zone in the northwest of the South China Sea, and for a more comprehensive seismic risk assessment of the Binhai fault zone in the future.
Key words：Qiongdongnan fault zone; northwestern South China Sea; structural characteristics; Binhai fault zone; scientific drilling
收稿日期：2022-05-30
基金项目：本文为国家自然科学基金项目(编号42106079，U20A20100)、南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(编号GML2019ZD0201，GML2019ZD0207)和中国地质调查局项目(编号DD20221719，DD20190627，DD20221712，DD20221714，DD20221696)联合资助的成果。
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