程世秀, 李三忠, 索艳慧, 刘鑫, 余珊, 戴黎明, 马云, 赵淑娟, 王霄飞, 安慧婷, 熊莉娟, 薛友辰. 南海北部新生代盆地群构造特征及其成因[J]. 海洋地质与第四纪地质, 2012, 32(6): 79-93. DOI: 10.3724/SP.J.1140.2012.06079
引用本文: 程世秀, 李三忠, 索艳慧, 刘鑫, 余珊, 戴黎明, 马云, 赵淑娟, 王霄飞, 安慧婷, 熊莉娟, 薛友辰. 南海北部新生代盆地群构造特征及其成因[J]. 海洋地质与第四纪地质, 2012, 32(6): 79-93. DOI: 10.3724/SP.J.1140.2012.06079
CHENG Shixiu, LI Sanzhong, SUO Yanhui, LIU Xin, YU Shan, DAI Liming, MA Yun, ZHAO Shujuan, WANG Xiaofei, AN Huiting, XIONG Lijuan, XUE Youchen. CENOZOIC TECTONICS AND DYNAMICS OF BASIN GROUPS OF THE NORTHERN SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2012, 32(6): 79-93. DOI: 10.3724/SP.J.1140.2012.06079
Citation: CHENG Shixiu, LI Sanzhong, SUO Yanhui, LIU Xin, YU Shan, DAI Liming, MA Yun, ZHAO Shujuan, WANG Xiaofei, AN Huiting, XIONG Lijuan, XUE Youchen. CENOZOIC TECTONICS AND DYNAMICS OF BASIN GROUPS OF THE NORTHERN SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2012, 32(6): 79-93. DOI: 10.3724/SP.J.1140.2012.06079

南海北部新生代盆地群构造特征及其成因

CENOZOIC TECTONICS AND DYNAMICS OF BASIN GROUPS OF THE NORTHERN SOUTH CHINA SEA

  • 摘要: 南海北部陆缘自西向东分布有北部湾、琼东南、珠江口和台西南等新生代盆地。前人认为这些盆地是华南大陆东南缘裂解直至南海北部被动陆缘形成过程中逐渐形成的,但大量地震剖面揭示,南海北缘主控盆断裂倾向陆地,与典型的被动陆缘的主断裂倾向海盆的特征明显不符。因而,南海北部陆架盆地成因显然不是被动大陆边缘的Mckenzie伸展机制。为此,基于大量陆地调查和海域地震剖面资料的对比,揭示了南海北部陆缘至少在34 Ma之前不是被动大陆边缘,早期陆缘断裂十分发育,主控断层为NE-NNE走向,和陆地同期走滑断层具有连续性。这些NNE-NE向断裂右行右阶走滑控制了拉分盆地内的EW或NEE方向的次级断裂,并控制了盆地内部近EW向的次级构造单元展布。因此,新生代南海北部陆缘的一系列盆地是动力学成因上具有密切联系的右行右阶拉分盆地群。这个拉分成因模式与南海北部陆缘新生代盆地内部沉积沉降中心迁移、构造跃迁、岩浆展布等特征非常一致。而南海北部真正成为典型被动大陆边缘的时间是在15 Ma之后,但此时南海却停止了扩张,而且大约在10~5 Ma由于菲律宾海板块沿吕宋岛弧-台湾造山带逐步楔入欧亚板块导致最后的弥散性NWW向断裂切割南海北部所有构造。从盆地动力学考虑,南海北部陆架盆地的成因主要与太平洋板块的动力学联系较为紧密。

     

    Abstract: There are a lot of Cenozoic basins from west to east in the northern margin of the South China Sea, including the Beibu Gulf, the Qiongdongnan, the Pearl River Mouth and the Taixinan basins.Previous studies suggested that these basins are derived gradually during the rifting of the southeast continental margin of the South China Block and the formation of the northern passive margin of the South China Sea.However, a large number of seismic profiles revealed that some major basin-controlling faults in the northern margin of the South China Sea are landward-dipping, which are clearly inconsistent with the major seaward dipping faults of a typical passive continental margin basin.Thus, the Mckenzie's extension model of passive continental margin remains controversial for the formation mechanism of the northern marginal basins of the South China Sea.This article, based on the comparison between a large number of field observation and marine seismic data, reveals that the northern continental margin of the South China Sea is not a passive continental margin before 34Ma.The early faults were well developed in NE-NNE-striking, corresponding to the strike-slipping faults in the southeast South China.These dextral, right-step strike-slipping faults are NE-NNE striking, controlling the secondary faults with near-EW or NEE strikes and the distribution of tectonic units in the pull-apart basins.Therefore, a series of Cenozoic basins in the northern margin of the South China Sea is dextral, right-step pull-apart basin group, having close relation in dynamics.This pull-apart model is consistent with the migration of sedimentary-subsidence centers and depocenters, tectonic jumping and magmatic migration within Cenozoic basins.The northern continental margin of the South China Sea actually became a typical passive continental margin since 15 Ma, when the South China Sea oceanic crust terminated spreading.At last, all structures in the northern continental margin of the South China Sea are offset by the late, diffusive NWW-striking faults resulting from the gradual indentation of the Philippines Plate to the Eurasian Plate along the Luzon Arc and the Taiwan Orogenic Belt between 10 Ma and about 5 Ma.Basin dynamics in northern continental margin of the South China Sea is mainly related to the dynamics of the Pacific Plate.

     

/

返回文章
返回