CORRELATION OF SURFACE SEDIMENTS WITH SINKING PARTICULATE MATTERS IN THE SOUTH CHINA SEA AND IMPLICATION FOR RECONSTRUCTING PALEOENVIRONMENT

The contents and distribution patterns of biogenic (carbonate, opal and organic carbon) and nonbiogenic (lithogenic matter) components in total 62 surface sediment samples which were taken from the South China Sea (SCS) are analyzed. Based on the sedimentary characteristics and the locations of deploying sediment traps, the SCS is divided into the N, C-NE, SW and S four subareas. Contents, depositional fluxes and distribution patterns of different components in surface sediments are correlated with those in sinking particulate matters and the relationship between export productivity from surface sediments, primary productivity from sinking particulate matters and export productivity at 100 m depth under euphotic zone is discussed. The results show that the average contents of most components in surface sediments are lower than those in sinking particulate matters, but the most depositional fluxes of carbonate and lithogenic matter in surface sediments are higher than those in sinking particulate matters. The average contents and depositional fluxes are not only influenced by the export level of each component from the water column, but also by the upper nutrition condition, terrestrial matter import and dissolution. The depositional fluxes of biogenic components in surface sediments are found to correspond to export productivity from surface sediments. However, influenced by terrestrial organic matter import and lateral drift of sinking bi-ogenic particulate matters, the export productivity from surface sediments does not correspond perfectly to the primary productivity from sinking particulate matters. The export productivity at 100 m depth under euphotic zone is apparently lower than export productivity from surface sediments in the SCS although the ratio of export productivity at 100 m depth under euphoric zone to the primary productivity from sinking particulate matters consists basically with the average "f" ratio of world ocean.