The Geochemcal Characterisitics And Their Paleoceanographic Significance Of Core S08-57 In The South China Sea

A sediment sample of core S08-57 from South China Sea were drilled out to study the paleo-oceanographic significance. The sediment samples of the core were analyzed in the contents of CaCO₃,SiO₂,Al₂O₃,TFe₂O₃,MgO,CaO,Na₂O,K₂O,TiO₂,P₂O₅,MnO,Cu,Pb,Zn,Co,Ni,Ba,Sr,Rb,V,Cr,La,Ce and Ta. According to the calcium carbonate, the author established the CaCO₃ chemostratigraphy and put forward the event SB4.0 of the South China Sea, make development of the standard CaCO₃ chemostratigraphy in South China Sea. The authors also discussed the geochemical characteristics and their paleoceanographic implications of core S08-57. The curves of Al₂O₃,TiO₂,Nb,SiO₂,K₂O,Ta,La,Rb,Ce,MgO,Zn,TFe₂O₃,Na₂O,V,Pb and Cr are very similar, all of them show the enantiomorphous relation to CaCO₃, and there is one strong CaCO₃ sediment event at SB3.33m. The result of R type clustering analysis of the 172 samples show that all the elements can be divided into 7 coalescences, 3 groups in sum. This paper has study the sedimentation and sediment source by elements and element ratios'change; the diagram LOI% vs CaO% of the core shows that the main sedimentations are terrigenous clasts and biogenous debris. The author has calculated the content of terrigenous matter, discussed the input change of terrigenous clasts, the submarine hydrothermal activity. According to the anomaly of Ce, the author has study the redox environment of the seafloor, the oxidation intensified at about 51ka B.P. and presented gyration duringδO4. This dissertation summarizes the research results about paleoproductivity in the South China Sea, calculates the content of bio-barium of the core and discusses the variational rule of paleoproductivity in succession.The author also studys the sediments type by the diagram of geochemical differentiation, the results show that the most of sediments are pelagic clay.