南海大陆边缘动力学:从陆缘破裂到海底扩张

边缘海如何形成是地球科学的基本问题.本研究通过对南海区域深反射地震数据及钻井数据的综合解释,聚焦地壳深部结构和三维全变形机制,在南海陆缘张裂-海盆扩张的构造动力学研究中取得重要进展:(1)"大陆破裂非均一":拉张过程垂向上分层非均一,受拆离断层系统控制;裂离过程横向上高度变化,中-东侧受岩浆作用主导,西侧受构造作用主导...

Continental Margin Dynamics of South China Sea:From Continental Break-Up to Seafloor Spreading

Opening mechanism of marginal basins is one of the fundamental issues of earth science. Based on integrated geological interpretations on deep-reflection seismic and drilling data in the South China Sea (SCS), this study analyzes the deep crustal structure and deformational patterns, the results show: (1) The extension and breakup process of the SCS was ununiform and highly variable, i.e. the continental margin experienced depth-dependent stretching dominated by detachment system, and the breakup process was "a magma-rich" type in the middle-east, but a "magma-poor" one in the west. (2) The spreading process of the SCS was unbalanced and asymmetric, featured with two episodic southward ridge jumps, as well as multiple changes of spreading orientation, resulting in the asymmetric post-spreading magmatism and inhomogeneous lithospheric structure. Base on above-mentioned research, we propose an opening model for tectonic-restricted marginal basins dominated by the West Pacific subduction, which is featured with highly variable continental rifting and ununiform seafloor spreading. The model can enrich the theory of continental margin dynamics.