Features of Late Cenozoic Deepwater Sedimentation in Southern Qiongdongnan Basin, Northwestern South China Sea

Based on high resolution 2D and 3D seismic data acquired in recent years, using sequence stratigraphy analysis and geophysical methods, we discuss the features of Late Cenozoic deepwater sedimentation in the southern Qiongdongnan （琼东南） basin. The study area entered a bathyal slope environment in the Miocene. The channel developed in the Sanya （三亚） Formation was controlled by a fault break, and its shingled seismic characteristics represent multiple erosion and fill, which may indicate that turbidite current developed in the slope environment. The polygon faults found in mudstone of the Meishan （梅山） Formation represent the deepwater hungry sedimentary environment. The large-scale channels developed on the top of Huangliu （黄流） Formation could be the result of a big sea level drop and an increase of sediment supply. The fantastic turbidite channel developed in Late Quaternary in the slope environment has ＂fan-like＂ body and long frontal tiny avulsion channel. The analysis of these features suggests that the sediment supply of the study area in the post-rifting period was dominant from the Vietnam uplift in the southwest. These deepwater sedimentary features could be potential reservoirs or migration pathways for deepwater petroleum systems.