Research on the dynamics of the South China Sea opening: Evidence from analogue modeling

• Published in: Science China. Earth sciences Vol. 49; no. 10; pp. 1053 - 1069
• Main Authors: Sun, Zhen, Zhou, Di, Zhong, Zhihong, Xia, Bin, Qiu, Xuelin, Zeng, Zuoxun, Jiang, Jianqun
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.10.2006; CAS Key Laboratory of Marginal Sea Geology,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China%CAS Key Laboratory of Marginal Sea Geology,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China%Department of Technology,Shenzhen Branch of CNOOC,Guangzhou 510240,China%CAS Key Laboratory of Marginal Sea Geology,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China%Faculty of Earth Sciences,China University of Geosciences,Wuhan 430074,China%Hainan Oil & Gas Exploration Company,Liaohe Oilfield PetroChina,Panjin 124010,China; CAS Key Laboratory of Marginal Sea Geology,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 510301,China
• Subjects: analogue; and; Cenozoic; China; clockwise; drifting; Geologic depressions; Geology; massifs; modeling; Plate tectonics; Rifting; rigid; River basins; River mouth; rotation; Sea; South; ISEW, South China Sea; ISEW, Borneo; China, People's Rep., Zhu R; South China Sea; rigid massifs; rifting and drifting; analogue modeling; clockwise rotation
• ISSN: 1674-7313; 1006-9313; 1869-1897; 1862-2801
• DOI: 10.1007/s11430-006-1053-6

Independent of Indochina extrusion, the South China Sea experienced a process from passive continental rifting to marginal sea drifting. According to the fault patterns in the Beibu Gulf basin and the Pearl River Mouth basin, the continental rifting and early spreading stage from 32 to 26 Ma were controlled by extensional stress field, which shifted clockwise from southeastward to south southeastward. From 24 Ma on, the sea spread in NW-SE direction and ceased spreading at around 15.5 Ma. Integrated geological information with the assumption that the South China Sea developed along a pre-Cenozoic weakness zone, we did analogue experiments on the South China Sea evolution. Experiments revealed that the pre-existing weakness zone goes roughly along the uplift zone between the present Zhu-1 and Zhu-2 depression. The pre-existing weakness zone is composed of three segments trending NNE, roughly EW and NEE, respectively. The early opening of the South China Sea is accompanied with roughly 15° clockwise rotation, while the SE sub-sea basin opened with SE extension. Tinjar fault was the western boundary of the Nansha block (Dangerous Ground),while Lupar fault was the eastern boundary of the Indochina, NW-trending rift belt known as Zengmu basin developed between above two faults due to block divergent of Indochina from Nansha. In the experiment, transtensional flower structures along NW-trending faults are seen, and slight inversion occurs along some NE-dipping faults. The existence of rigid massifs changed the orientations of some faults and rift belt, and also led to deformation concentrate around the massifs. The rifting and drifting of the South China Sea might be caused by slab pull from the proto South China Sea subducting toward Borneo and/or mantle flow caused by India-Asia collision.