The crustal structure of South China Sea continental slope

The sea-floor spreading of the South China Sea (SCS) was stopped since Miocene; this probably means that the plate tectonics in the SCS is in a stable situation. According to the magnetic anomaly, the sea-floor spreading of SCS was started in Oligocene and stopped in Miocene, and the continental rifting probably happened around Mesozoic. There are many differences between the northern and the southern sides of SCS. As we can see in the SCS regional map; the northern side is the continental shelf covered by thick sediments; and the southern side are numerous coral reef islands, the Spratly islands, covered up to 2-3 km thick of carbonates. Based on the seismic profiles, it shows a serial of normal faults in the northern side, and in the southern side are normal faults and thrust faults with different slip directions. The southern side has also a long history related to the formation of the reef islands. It probably means that the early continental rifting of the SCS is the passive Atlantic type shear processes. During 8/20 ¡V 9/11, 2007, we have conducted a two-ship MCS/OBS study in the northern continental slope of the SCS. Previously, the area had been surveyed by a China-Japan OBS study in 1983, the US Columbia University for an ESP study in 1985, a China-German OBH study in 1996, and a Taiwan-China MCS/OBS study in 2001. All are aiming to better understand the crustal structure of the SCS continental shelf.