Tectonic Stratigraphic Framework of the Yinggehai‐Qiongdongnan Basins and Its Implication for Tectonics Province Division in South China Sea
Tectonic Stratigraphic Framework of the Yinggehai‐Qiongdongnan Basins and Its Implication for Tectonics Province Division in South China Sea
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DOI：
10.1002/cjg2.1689
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发表时间：
2011-11
期刊：
影响因子：
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通讯作者：
Jianye Ren;C. Lei;Shanshan Wang;Tao Li;Xiaoli Zhang
中科院分区：
文献类型：
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作者：
Jianye Ren;C. Lei;Shanshan Wang;Tao Li;Xiaoli Zhang
莺歌海盆地和琼东南盆地是东南亚最大的新生代沉积盆地之一。通过对盆地区域地震剖面的构造-地层分析，在古近系充填序列中，提出了一个突出的区域构造演化边界T70。T70界线具有明显的截断和上超特征，其年龄为32~30 Ma，与南海洋脊的形成和扩张相一致。该界线将古近纪沉积划分为两个构造地层单元，即莺歌海盆地和琼东南盆地的下部断陷层、琼东南盆地的上部断陷层和莺歌海盆地的凹陷层。莺歌海盆地和琼东南盆地的构造地层单位和构造演化边界是对东南亚板块重组的原始响应。结合前人的工作，本研究认为，东南亚可划分为碰撞挤压构造省和原南海板拉构造省。阐明了两个构造省不同的构造特征、不同的演化历史和动力学背景。它们的边界是红河断层的转换边界，沿着越南边缘向南延伸，并沿着卢帕尔线与海沟相连。结合本文的动力学变形分区，明确了莺歌海盆地和琼东南盆地的动力学机制及其演化模式。该研究将加深对南海及其周边地区发展演化的认识，对南海大陆边缘动力学和油气勘探具有重要意义。
The Yinggehai and Qiongdongnan basins together form one of the largest Cenozoic sedimentary basins in SE Asia. Here we present a prominent regional tectonic revolution boundary T70 in the Paleogene filling sequence based on structure-stratigraphic analysis of regional seismic profiles in the basins. The T70 boundary, characterized by distinct truncation and onlap seismic reflections, was dated 32~30 Ma, consistent with the onset and spreading of South China Sea oceanic ridge. This boundary separated two tectonic-stratigraphic units in the Paleogene sediments, e.g the lower faulting-controlled subsidence layer in the Yinggehai and Qiongdongnan basins, the upper faulting-sag layer in the Qiongdongnan basin and the sag layer in Yinggehai basin. The tectonicstratigraphic units and tectonic revolution boundaries in the Yinggehai and Qiongdongnan basins were the original responses to reorganization of plates in SE Asia. In combination with previous work, this study suggests that SE Asia can be divided into collision-extrusion tectonic province and proto-SCS slab pull tectonic province. We clarify distinct structure features, different evolution histories and dynamic settings of the two tectonic provinces. They are bounded by a transform boundary of the Red River fault extending south along the Vietnamese margin and joining with the trench along the Lupar Line. Considering the dynamic deformation division in this paper, the dynamic mechanisms and their evolution models for the Yinggehai and Qiongdongnan basins have been clearly determined. Our research will improve understanding on the development and evolution of the South China Sea and its peripheral areas, and has great significance for geodynamics of the continental margins and petroleum exploration in the South China Sea.