红河断裂与南海西缘断裂对接处的构造特征及演化过程

The Red River Fault zone and the Western-edge Fault zone of South China Sea (SCS) are the tectonic boundary between the SCS and the Indochina Peninsula. The two fault zones connect with each other at the southwest of Hainan Island, however the extension direction of the Red River Fault is unknown after its passing through the area. The geologic structures and its evolution process of the connection area between the two fault zones may contain important information about the extension direction of the Red River Fault. In the past, due to the influence of limited deep sea exploration technology and the geopolitical factors, it is difficult to implement and make a breakthrough by traditional structural geological research methods. Therefore, the study on the tectonic characteristics and evolution process has not been thoroughly carried out. What are the structural, tectonic features and tectonic evolution process in the connection zone? What is the intertwined relationship between the two faults? How do the structural characteristics and the evolution process of the connection indicate the direction of the extension of the Red River Fault zone? In order to answer these scientific questions, our study intends to interpret the geologic structure characteristics of the connection through the latest geophysical data, and establishes the corresponding structural geological model. Then we use FLAC numerical simulation software to simulation its deformation and stress process, to reveal the tectonic evolution process and the dynamic mechanism of the connection, and provide the basis on the extension direction of Red River Fault zone after crossing through the area. Also this study is significant for deeply understanding the formation of the SCS and the evolution of the regional petroliferous basins.

红河断裂带和南海西缘断裂带是南海与印支半岛之间的大地构造边界，两者在海南岛西南部海域对接，红河断裂入海经过该海域后其延伸方向不明，因此该对接处的地质构造特征及其演化过程可能蕴含着红河断裂延伸方向的重要信息。由于过去深海探测技术有限及地缘因素影响，传统构造地质的研究方法较难实施，造成该处构造特征及演化过程的研究还未深入开展。红河断裂带和南海西缘断裂带的对接处具有怎样的结构、构造特征，两断裂的交切关系如何，以及构造演化过程是怎样的？两断裂对接处的构造特征及演化过程对红河断裂的延伸方向有何指示作用？为回答以上科学问题，本项目拟通过该海域最新的地球物理资料，解译该对接处的地质构造特征，并建立相应的构造地质模型，运用FLAC数值模拟软件对其变形、应力作用过程进行模拟，揭示对接处的构造演化过程及动力学机制，为深入探讨红河断裂的延伸方向提供依据。这对于深入认识南海形成及区域含油气盆地发育也具有重要意义。