The South China Sea (SCS) is the largest marginal sea in the West Pacific. Previous biostratigraphic studies on calcareous nannofossils in the SCS were limited to incomplete Oligocene to Pleistocene marine sequences from exploration wells in offshore basins (Duan and Huang, 1991; Huang and Zhong, 1992; Xu, 1996; Huang, 1997) or late Quaternary materials from shallow piston cores in the deep-sea area (Duan, 1985; Su, 1989).
During Ocean Drilling Program (ODP) Leg 184 (Fremantle to Hong Kong, February–April 1999), the JOIDES Resolution drilled six sites in the deep-sea area of the SCS. This was the first time that sediment cores deeper than 20 m were sampled from the continental slope in the SCS. Of these six sites, Sites 1146 and 1148 were the source of the two longest sections from the SCS: a 642-m-long composite section spanning the last 18 m.y. at Site 1146 and an 861-m-long composite section spanning the last 32 m.y. from Sites 1147 and 1148. Sediments recovered at these two sites yield abundant and well-preserved calcareous nannofossils.
The objective of this study was to establish an early Oligocene to Pleistocene calcareous nannofossil biostratigraphic framework for the northern SCS.