Quaternary sequence stratigraphic evolution of the Pearl River Mouth Basin and controlling factors over depositional systems

Based on the seismic, well logging and paleontological data, the sequence stratigraphic evolution of the northeastern shelf margin of the Pearl River Mouth Basin and the controlling factors on depositional systems since Quaternary are studied in this paper. Quaternary depositional systems in the study area are characterized by large-scale foresets complexes, which can be further subdivided into four 3^rd order sequences, in each of which lowstand, transgressive, highstand systems tracts are observed. Depositional systems recognized in the slope section include slope incised valley, NW-SE oriented unidirectional migration of shelf-margin channels, shelf margin deltas, slope fans, and high-angle progradational complexes. As sea level fell down and/or sediment supply increased, deltaic systems prograded onto shelf-margin, and formed a series of thick shelf-edge deltas and finally deposited as slope fans. Since Pleistocene, these prograding complexes have been formed from the southern Panyu Lower Uplift toward the northern Baiyun Depression. At the same time the shelf slope break migrated to the sea. Incised valley of continental shelf increased upwards and reached a peak at SB3 and SB2. The Holocene highstand delta was limited within the continental shelf after the latest transgression. The evolution of depositional systems of continental slope is mainly controlled by the combination of sea-level changes, tectonic movement, climate changes and sediment supply.