South China Sea is located to the east of Vietnam, west of Philippines and the Luzon Strait, and north of Borneo.
The collision thickened the continental crust and changed the elevation of the topography from the Himalayan orogenic zone to the South China Sea, especially around the Tibetan Plateau.
All the plates around the South China Sea Basin underwent clockwise rotation, subduction and experienced an extrusion process from the early Cenozoic to the Late Miocene.
The rifting and multiple grabens initiated around 55 Ma,[1] based on seismic profiles across the southern China Shelf.
The north and northeastern parts of the South China Sea formed their rifts earlier in the Paleocene.
Cullen indicated that the South China Sea Basin's rifting could be traced back to the late Cretaceous and the extension concluded in two episodes during the Cenozoic.
The first rift system was located mainly in the Dangerous Ground (SE of South China Sea [3] and in the Phu Khanh Basin, offshore central Vietnam.
[4] The later episode of extension appeared from late Eocene to Early Miocene and propagated towards the southwest.
Tonalitic granite contains higher content of Ti, Al, Fe, Mg, Ca, Na and P, less Si and K, and could be derived from melting of the mantle and lower Precambrian crust.
There are three main models that try to interpret how the opening and formation of the South China Sea happened over long periods of geological time.
Although this model explains the geometrical change of the South China Sea Basin during its tectonic evolution, it is still vague on some parts especially in relation to the rotation of Borneo.
[9] This model also proposes that no subduction occurred along the north side of Borneo, which is hard to explain given the existence of thrust faults in the SE South China Sea Basin.
The subduction zone migrated towards the southeast of the South China Sea, which matches with the former convergent boundary along the northern edge of the Borneo Block.
Due to the unique location of the South China Sea during the Cenozoic, with a subduction zone on east side, the Red River shear zone on the west, and the jumping of the spreading ridge to the south, different but mostly extensional faults developed and caused subsidence forming a basin.
The north and northwest parts of the South China Sea are surrounded with rift basins on the passive continental margins.
Gong et al. (2011),[15] based on extensive drilling results and multichannel seismic data, documented the impacts of these tectonic activities on the deposition of source, reservoir and seal rocks and on the formation of various types of trapping mechanism.
The former's subsidence history however has been influenced by an additional tectonic element, the wrenching movements along the Red River Fault System.
[17] Clockwise rotation of the Indochina block along the Red River Fault System has been attributed to the transtensional stresses in the basin.