BASIN DYNAMICS AND BASIN GROUPS OF THE SOUTH CHINA SEA

The South China Sea was formed in Cenozoic. Basins in the South China Sea could be divided into different types, such as continental shelf basins, continental slope basins and deep sea basins, which are closely related with the rifting and transition of the continental margins, and thus could be grouped into strike-slip-related pull-apart and extensional basins, extrusion-escape-related rifting basins, extension-and subduction-related buckling basins. They developed further into some ridge-spreading-related oceanic sub-basins in different stages. These basins were formed not under a single dynamics but under a very complex and changeable dynamics. These basins have suffered from a series of Cenozoic tectonic movements, such as the Shenhu, the South China Sea, the Dongsha, resulting in the formation and spatial-temperal migration of complex angular unconformities in these basins. Accompanying with the tectonic migrations and evolutions in these basins, faulting, magmatism, shifting of sedimentary subsidence centers and depocenters, oil accumulation and geohazards show a significant feature of jumping. The complex dynamic settings of the South China Sea have caused many controversies on their origin. The plate dynamic factors include the Pacific Plate subduction and the indentation of the Philippine Sea Plate along the Taiwan Orogen to the east side of the South China Sea, and the Indian Plate oblique subduction and mid-ocean ridge subduction to the west side. They may also be responsible for the uplifting of the Tibetan Plateau and the related extrusions of continental blocks to the north side. At the same time, the mantle dynamics of deep-seated magma underplating, delamination, mantle plume and mantle-hydrated process should not be ignored. At last, this paper proposes one strike-slipping pull-apart model to explain the onset of the South China Sea Basin which is closely related to the tectonic evolution of the Pacific Tectonic Domain.