被动大陆边缘张-破裂过程与岩浆活动:南海的归属  

The Rifting-Breakup Process of the Passive Continental Margin and Its Relationship with Magmatism: The Attribution of the South China Sea

作　　者：孙珍[1,2,3,4] 李付成 林间[1,2,3] 孙龙涛 庞雄 郑金云[5] Sun Zhen;Li Fucheng;Lin Jian;Sun Longtao;Pang Xiong;Zheng Jinyun(Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences,Guangzhou 511458,China;Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou),Guangzhou 511458,China;China-Pakistan Joint Research Center for Earth Sciences,Islamabad 45320,Pakistan;Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology,Qingdao 266237,China;CNOOC Deepwater Development Limited,Shenzhen 518054,China)

机构地区：[1]中国科学院边缘海与大洋地质重点实验室,南海海洋研究所,南海生态环境工程创新研究院,广东广州511458 [2]南方海洋科学与工程广东省实验室(广州),广东广州511458 [3]中国-巴基斯坦地球科学研究中心,巴基斯坦伊斯兰堡453204 [4].青岛海洋科学与技术试点国家实验室,海洋矿产资源评价与探测技术功能实验室,山东青岛266237 [5]中海石油深海开发有限公司,广东深圳518054

出　　处：《地球科学》2021年第3期770-789,共20页Earth Science

基　　金：广东省自然科学基金研究团队项目(No.2017A030312002);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(Nos.GML2019ZD0104,2019BT02H594,GML2019ZD0205);王宽诚教育基金项目(No.GJTD-2018-13)。

摘　　要：岩浆在被动大陆边缘的张-破裂过程中起到决定性作用.南海东北部陆缘发育厚度达10 km的下地壳高速体,其成因机制长期存在争议,影响了对南海东北部陆缘构造归属的界定.为了分析南海共轭陆缘的张破裂机制,本文调研了国内外最新研究进展,系统分析了南海南北陆缘的地壳结构和岩浆活动特点,提出:南海陆缘和海盆中发育有大量岩浆活动,但东西陆缘存在较大差异,底侵高速体东厚西薄,推测为同张裂成因.根据地壳结构与底侵岩浆的量,将被动陆缘划分为5个子类,南海陆缘东侧为多岩浆型,向西变为少岩浆型.东西差异除与伸展速率有关,可能还与东侧陆缘发生了板缘破裂,而西侧陆缘发生了板内破裂有关.Magma plays a key role in the rifting and breakup process of passive continental margin. Up to 10 km thick high velocity lower crust(HVLC) developed in the northeastern margin. Long term controversy toward its formation mechanism makes the margin classification difficult. In order to analyze the rifting and breakup mechanism of the SCS conjugate margins, this paper reviews the recent research progress of global margins, based on which the crustal structure and magmatic activity of the SCS are summarized. It is concluded that large amounts of magmatic activity occurred in the SCS with discrepancy between the eastern and western margins. The HVLC is thicker in the east and thinner or even absent in the west. It is speculated that the HVLC is of syn-rift underplating. According to the crustal structure and the amount of underplated magma, we suggest that the passive continental margin can be divided into 5 subclasses. The eastern continental margin of the SCS is of magma-robust type, and the middle and western margins are of magma-intermediate and magma-deficient types, respectively. In addition to the stretching rate, plate-edge rifting in the east and plate-interior rifting in the west continental margin may also contribute to the large difference in the amount of magmatic underplating.

关 键 词：被动大陆边缘 张裂与破裂 岩浆作用 南海 板内与板缘破裂 海洋地质 

分 类 号：P736[天文地球—海洋地质]