SEISMIC CHARACTERISTICS AND DISTRIBUTION OF PLIOCENE MASS TRANSPORT DEPOSITS IN CENTRAL CANYON OF QIONGDONGNAN BASIN: SEISMIC CHARACTERISTICS AND DISTRIBUTION OF PLIOCENE MASS TRANSPORT DEPOSITS IN CENTRAL CANYON OF QIONGDONGNAN BASIN

2D/3D seismic data and coherence of 3D seismic data in the deepwater area of Qiongdongnan Basin reveal the occurrence of multi-stage mass transport deposits(MTDs) in the Central Canyon of the basin.The MTDs of this region consist of three units,namely the headwall domain,the translational domain and the toe domain characterized by different seismic characteristics.Being regarded as an important part of deepwater deposition in the Central Canyon of Qiongdongnan Basin since Neogene,the large-scale MTDs have an important effect on the spatial distribution of sediment in the deepwater basin.The Pliocene MTDs are distributed in an area of 300 km2,with a thickness up to 240 m in a fan shape in planar distribution.The rapid sedimentary discharge and active tectonic movement may be the main reasons for the development of the MTDs in Central Canyon of Qiongdongnan Basin..In addition,earthquakes and fluctuation of sea level have a significant effect on the formation of the MTDs.