莺歌海盆地形成与演化的动力学机制

DYNAMICAL MECHANISM FOR GENERATION AND EVOLUTION OF YINGGEHAI BASIN,THE SOUTH CHINA SEA

莺歌海盆地位于印支半岛与南海北部大陆边缘交接区,复杂的地质构造背景使其形成演化的动力学机制成为国内外的研究焦点。从区域动力学演化的角度,系统分析了影响莺歌海盆地发育的印支地块构造演化特征,认为莺歌海盆地构造演化主要受印支半岛早期的逃逸挤出构造和晚期的挤压—伸展构造系统影响(或控制),在此动力学驱动机制下,莺歌海盆地新生代以来的构造演化经历了3个阶段,即左旋走滑—伸展裂陷阶段、中下地壳韧性伸展—热沉降阶段和加速沉降阶段。

Yinggehai basin is located in the juncture area between IndoChina continental block and northern continental margin of the South China Sea. Dynamical mechanism for generation and evolution of Yinggehai basin has become the debated focus due to its complicated tectonic setting.The authors have studied the tectonic evolution features of IndoChina block systemically, which puts significant effects on the development of Yinggehai basin. It suggests that the escapeextrusion tectonic and compressionextension tectonic systems are the main factors controlling the tectonic evolution of the basin. Three tectonic evolution phases are characteristic of Yinggehai basin. They are sinistral strikeslip extension phase, middlelower crust ductile extension and thermal subsidence phase, and accelerated subsidence phase.