Research on the dynamics of the South China Sea opening: Evidence from analogue modeling
Research on the dynamics of the South China Sea opening: Evidence from analogue modeling
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DOI：
10.1007/s11430-006-1053-6
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发表时间：
2006-10
期刊：
影响因子：
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通讯作者：
Zhen Sun;Di Zhou;Zhihong Zhong;B. Xia;X. Qiu;Z. Zeng;Jianqun Jiang
中科院分区：
文献类型：
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作者：
Zhen Sun;Di Zhou;Zhihong Zhong;B. Xia;X. Qiu;Z. Zeng;Jianqun Jiang
不受印度支那挤压作用的影响，南海经历了从被动大陆裂谷到边缘海漂移的过程。根据北部湾盆地和珠江口盆地的断裂模式，32 ~ 26 Ma的大陆裂陷和早期扩张阶段受伸展应力场控制，由东南向南东南顺时针方向移动。从24 Ma开始，海向西北-东南方向扩散，至15.5 Ma左右停止扩散。综合地质资料，假设南海沿前新生代软弱带发育，对南海演化进行了模拟实验。实验结果表明，原有软弱带大致沿现今珠1坳陷与珠2坳陷之间的隆起带移动。预存弱带由北北东向、大致东东向和北东东向三段组成。南海早开伴随着约15°顺时针旋转，而东南海底盆地早开伴随着东南扩张。亭贾尔断裂是南沙地块（危险地）的西界，卢帕尔断裂是印度支那的东界，由于印度支那地块从南沙向外扩张，在这两条断裂之间发育了北西向的曾母盆地裂谷带。实验中，沿北西向断裂可见张拉花状构造，部分北东向断裂出现轻微反转。刚性地块的存在改变了部分断裂和裂谷带的走向，也导致了地块周围的变形集中。南海的裂陷和漂移可能是由原南海板块向婆罗洲俯冲的板块拉移和（或）印度-亚洲碰撞引起的地幔流引起的。
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.