On tectonic framework and evolution of the South China Sea

Based on gravity-magnetic data, 17 deep major faults as well as 10 gravity-magnetic anomaly area have been identified in the South China Sea (SCS) and its adjacent area. Combined these results with other geological material, 7 tectonic units which have different geological structures can be divided in the SCS and its adjacent area. A uniform basement once formed in the Early Cretaceous in the SCS, and broke up during the Cenozoic. This breakup process experienced two tectonic events which happened one after another in spatial and overlapped. The first one was the shrinking, closing of the pro-SCS as well as collisions of blocks which located between the Sunda block and the Cathaysia archicontinent. The other one was the Nansha block broken up from the Cathaysia archicontinent, accreted to the Sunda block and associated with the continous expansion of the new SCS until to the Middle Miocene. Regional tectonic evolution had controlled the distribution of sedimentary basins in the SCS, forming "three basin belts in North continential margin, three basin belts in South continential margin, and one basin belt in East continential margin and one basin belt in West continential margin", which further controlled distributions of oil and gas enrichment area.