The depositional model of Xisha Trough

Xisha Trough was formed by undercompensation which was caused by fast structure subsidence since the late Miocene in Qiongdongnan Basin. Upside Xisha Trough with high angle belonged to aerosol deposition system, lower side Xisha Trough with low angle belonged to turbidite and slump system, bottom Xisha Trough with gentle area belonged to fluvial system. Different from turbidite which was small and apart, fluvial deposition is stable grand reservoir which distributed widely in the trough, and it is the major target of deep water oil gas exploration in the world.