SEDIMENTARY GEOCHEMISTRY IN CORE NT2 OF THE SOUTH YELLOW SEA AND ITS PROVENANCE

Geochemistry analysis and provenance discriminations are done for core NT2 from the South Yellow Sea near Jiangsu coast. Provenance of sediments in this core is mainly the Yangtze River and the Yellow River. Of the core,the uppermost layer of 0-5.50 m is characterized by sharp drop of K₂O,Na₂O, MgO,CaCO₃ and Sr,and enrichment of Li,V,Cr,Co,Ni,Cu,B,and Ga. Sediments are dominated by sandy silt and silt;the 5.50-19.40 m layer shows the increase of Al₂O₃,Mag,K₂O,CaCO₃,Li,V,Cr,Rb,Ni,Cu, and Sr with the increase of depth,but contents of SiO₂ and Na₂O have the opposite tendency. Sediments also consist of sandy silt and silt. Sediments of these two layers mainly come from the Yangtze River; the 19.40-27.00 m layer is rich in Al₂O₃,CaO,MaO,CaCO₃,Li,V,Cr,Co,Ni,Cu,and Zn,and Al₂O₃ and K₂O contents become higher downwards,while Na₂O and Sr are just the opposite. Sediments are mainly sandy silt,silty sand and sand from the Yellow River;the 27.00-54.60 m layer is rich in Al₂O₃,K₂O,MaO, TiO₂, CaCO₃, CaO, Li, V, Cr, Ni, B, Ga, and Rb, and sediments are mainly silt and sandy silt corresponding to nearshore shallow sea environment; the 54.60-70.31 m layer shows an enrichment of SiO₂, Na₂O, MnO, St,and Ba,and sediments are gray fine sand with dark gray silty clay thin layer in the upper and fine sand and silty fine sand in the lower. Sediments below the 54.60 m depth is mainly from the Yangtze River. The research results indicate that the Yellow River had an obvious effect on sedimentation of the South Yellow Sea during the middle-late period of middle Pleistocene and the Yangtze River mainly controlled the sedimentation of the study area during the early period of late Pleistocene.