PROGRESS IN QUATERNARY PALEOCEANOGRAPHY OF THE SOUTH CHINA SEA: A REVIEW
南海第四纪古海洋学研究进展

The last five years have witnessed a rapid progress in Quaternary paleoceanographic studies in the South China Sea (SCS). From Sonne 95 Cruise in 1994 toODP Leg 184 in 1999, a series of intemational expeditions have been devoted topaleoclimatic records in the SCS, with emphasis laid on evolution and variations ofthe East Asian monsoon system. Up to now, at least 150 deep-water sediment coreshave been analyzed from the SCS (Fig. 1), with a progressive increase in corenumbers and analysis items (Table 1).Based on an integrated approach with biostratigraphic, magnetostratigraphic,isotope and carbonate stratigraphic methods applied, the Pleistocene stlatigraphicsequence is for the first bine established in the Nansha area of the southern SCS(Core 17957). Bio-events of four microfossil groups were used for its stratigraphy;planktonic foraminifers, radiolarians, nannofossils, and benthic foraminifers (Fig. 2,Table 2). A site with extremely high sedimentation rates from the northern slope(Core 17940) has Provided high-resolution records of the last 40 000a, with samplinginterval equal to less than 20 years (Fig.3).Various methods of paleo-SST estimations have shown a much more significantglacial / interglacial contrast in the SCS than in the open ocean, proving the"amplifying effect" of the marginal sea. Rescent studies on the fluctuations ofthermocline and the changes of deep-water masses have greatly improved ourunderstanding of the history of upper ocean structure and deep-water paleoceanographyof the SCS (Fig.4).The fine-gain size analysis of terrigenous material and the pollen analysis haverevealed a correlation between the monsoon and glacial cycles. In general, thesummer monsoon intensifies during interglacial, while winter monsoon strengthens inglacial stages. The SCS cores have recorded also the monsoon fluctuations onmillennial bine scale, as shown by both pollen and isotope analyses. Due to theintensification of winter monsoon, the climate contrast between the northern andsouthern parts of the SCS is remarkably enhanced during the glacial.Rescent progress in deep-Sea sedimentological studies, such as sediment flux,volcanic ash and microtektite, is also reviewed. The paper concludes with somesuggestions for the further paleoceanographic studies in the SCS.