Radiometric dates of key rock units indicate that a remnant Late Mesozoic ocean of the Huatung Basin is still preserved today east of the South China Sea (SCS). We integrate regional geology with a Cretaceous oceanic basement in the vicinity of the Huatung Basin to reconstruct the Huatung Plate east of the Eurasian continent. Results of geophysical investigations, four expeditions of deep-sea drilling and a renaissance of regional geology allow us to propose a hypothesis that the mechanism responsible for the SCS opening was raised from strike-slip fault on the east. The hypothesis suggests that the SCS opening could highly relate to the strike-slip faults inherited from Late Mesozoic structures onshore–offshore the SE Cathaysia Block to develop rhombic-shaped extensional basins en echelon on the thinned Eurasian continental crust in the Early Cenozoic. It was followed by sinistral strike-slip movements along the boundary between the Eurasian Plate and the Huatung Plate driven by oblique subduction of the Huatung Plate to the northwest coupled with slab-pull force by southward subduction of the Proto-SCS to open up the triangle-shaped oceanic East Sub-basin in the Early Oligocene (33/34 Ma). The spreading ridge then propagated southwestward in the step-over segment between the Zhongnan-Lile and the Red River strike-slip fault systems to open the triangle-shaped oceanic Southwest Sub-basin by 23 Ma. The plate boundary fault was subsequently converted into the Manila Trench when the Eocene Sierra Madre arc of the Huatung Plate had moved from the south to its present latitude by the Middle Miocene.

中文翻译：

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走滑断裂对南海开放的潜在作用

关键岩石单元的辐射测年表明，华东盆地的晚中生代残余洋今天仍然保存在南海以东（SCS）。我们将区域地质与华东盆地附近的白垩纪海洋基底相结合，重建欧亚大陆以东的华东板块。地球物理调查的结果、四次深海钻探和区域地质学的复兴使我们提出了一个假设，即南海开放的机制是由东部的走滑断层引发的。该假说表明，南海的开口可能与东南华夏地块陆上-海上的晚中生代构造继承的走滑断层高度相关，从而形成梯形菱形伸展盆地。在早新生代变薄的欧亚大陆地壳上。随后，华东板块向西北倾斜俯冲，加上原南海向南俯冲的板片拉力，沿欧亚板块与华东板块交界处发生左旋走滑运动，打开三角区。早渐新世 (33/34 Ma) 形状的洋东亚盆地。扩张脊随后在终南-里乐和红河走滑断裂系统之间的跨界段向西南方向传播，将三角形洋西南次盆地打开了23 Ma。当华东板块始新世马德雷弧由南移至中中新世时，板块边界断层随后转变为马尼拉海沟。