Pollen record of the last 280 ka from deep sea sediments of the northern South China Sea

Environmental history of the northern continental shelf of the South China Sea during the last 280 ka BP, e.g. Marine Isotope Stages 1–8 (MIS 1–8) was reconstructed based on pollen record from the top 225m of ODP 1144 Site. During the interglacial periods, pollen assemblages are predominated by pine similar to those of the present day indicating that the environment of the interglacial periods was more or less close to that of today. Nevertheless, those from glacial periods are characterized by a large amount of herbaceous pollen, e.g.Artemisia, Gramineae, Cyperaceae, etc. inferring that grassland covered the merged continental shelf when the sea level lowered and the continental shelf was exposed. The exposed areas of the shelf were insignificant before MIS 5, but enlarged since MIS 4 and reached its maximum during MIS 2 according to ratios of pollen percentages between pine and herbs. The history of different exposure of the shelf can be compared with transgression records of the coastal areas of China and might result from neotectonic movement of Chinese continent. Some changes also took place in the components of grassland growing on the shelf during glaciations. Gramineae is the main element at MIS 8. ThenArtemisia increased upwards the profile and at last became the main component at the Last Glacial Maximum (MIS 2). Such changes in vegetation might be in response to cooler and drier climate.