南海北部被动陆缘洋陆转换带张裂–破裂研究新进展  

New developments on the rift-breakup of the continent-ocean transition zone in the northern margin of the South China Sea

作　　者：赵明辉[1,2] 袁野 张佳政 张翠梅[1] 高金尉[4] 王强 孙珍 程锦辉[1,2] ZHAO Minghui;YUAN Ye;ZHANG Jiazheng;ZHANG Cuimei;GAO Jinwei;WANG Qiang;SUN Zhen;CHENG Jinhui(Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 511458,China;University of Chinese Academy of Sciences,Beijing 100049,China;Guangzhou Marin Geological Survey,Key Laboratory of Seabed Mineral Resources,Ministry of Natural Resources,Guangzhou 511458,China;Institute of Deep-sea Science and Engineering,Chinese Academy of Sciences,Sanya 572000,China;Xiamen Institute of Geological Engineering,Xiamen 361008,China)

机构地区：[1]中国科学院边缘海与大洋地质重点实验室,中国科学院南海海洋研究所,广东广州511458 [2]中国科学院大学,北京100049 [3]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511458 [4]中国科学院深海科学与工程研究所,海南三亚572000 [5]福建省厦门地质工程勘察院,福建厦门361008

出　　处：《热带海洋学报》2024年第2期173-183,共11页Journal of Tropical Oceanography

基　　金：国家自然科学基金项目(91958212、41730532、U20A20100);广东省基金团队项目(2017A030312002)。

摘　　要：文章基于深地震探测数据与大洋钻探资料,研究了南海北部被动陆缘洋陆转换带张裂–破裂机制科学问题。2018-2023年在国家基金委共享航次的协助下,实施了三维深地震探测实验,共投放海底地震仪52台次,海底电磁仪2台次,放炮数量达8750炮,累积获得了294Gb的第一手数据,并取得了一系列的创新性成果:1)首次获得南海北部陆缘洋陆转换带深达上地幔的三维速度结构,精准确定了研究区洋陆转换带三维空间展布范围宽度为10~20km;2)揭示南海北部陆缘异常活跃的岩浆作用,提出了不同时间段的构造与岩浆相互作用方式,岩浆活动随着伸展作用不断向洋迁移并逐渐占据主导地位;3)建立了边缘海独特的张裂–破裂地质演化模型,最后一期强烈的岩浆活动导致岩石圈破裂,形成由玄武岩为主的“鳄鱼嘴”构造,同时张裂–破裂过程沿其陆缘走向又存在显著的构造–岩浆差异性。Based upon the deep seismic data and IODP drilling results,this study focuses on the mechanism of rifting and breakup processes of the northern South China Sea.During the implementation of the project(2018—2023),a 3D deep seismic survey was carried out during the Chinese National Natural Science Foundation Open Research Cruise(No.NORC2018-08).A total of 52 ocean bottom seismometers(OBSs)and 2 ocean bottom electro-magnetometers(OBEM)were deployed and a total of 8750 shots were fired.49 OBSs and 1 OBEM have been recovered,and a large amount of data(294 GB)have been acquired.At the same time,a series of innovative results are obtained:1)the 3D velocity structure of the COT in the northern margin of the SCS has been obtained for the first time,and the COT domain with width of 10~20 km is determined in 3D view;2)the active magmatism was revealed in the northern margin of the SCS,and the styles of interaction between tectonism and magmatism were proposed in different geological stages;meanwhile,the magmatism propagated seaward and progressively increased during extension;3)the geological model of rifting and breakup is established as the type of marginal seas,whose breakup occurred in a crocodile style dominated by basalt due to the strong magmatism during end-rifting,accompanied with significant along-strike variations in the tectonism and magmatism.This project builds up the opening mode of the SCS from the perspective of 3D deep seismic data,and promotes the Chinese basic research of the marginal sea,which has far-reaching scientific and strategic significances.

关 键 词：洋陆转换带 二维/三维深部结构 海底地震仪 张裂–破裂机制 南海北部陆缘 

分 类 号：P738.4[天文地球—海洋地质]