PLIOCENE-QUATERNARY SHELF-EDGE DEPOSITIONAL SYSTEMS ON THE NORTHERN SLOPE OF BAIYUN SAG, THE PEARL RIVER MOUTH BASIN

Based on the high resolution multi-channel seismic data, drilling cores and well logs data, the Pliocene-Quaternary isochronous stratigraphic framework is established for the northern slope of the Baiyun Sag. Typical depositional systems are recognized on the northern shelf-edge and their controlling factors are preliminarily discussed in this paper. Our study shows that there are three third-order sequence boundaries, namely, T₀(seafloor),T₁ (1.8 Ma), T₂ (5.3 Ma) and two third-order sequences, i.e. A and B within the Pliocene-Quaternary deposits. Seismic facies, such as the sheet-like parallel-subparallel seismic facies, broom-like foreset seismic facies, lenticular foreset seismic facies, and filling seismic facies are identified. The seismic facies are products of specific types of deposition controlled by the topography of the shelf break, sea level change, sediment supply and other factors. Large-scale shelf edge deltas and extensive deep water channels have been developed in the study area since Pliocene. Channels provide conduits for transportation of terrigenous materials to the lower slope and abyssal basin.