摘要:
对苏北岸外南黄海陆架区NT2孔岩心进行了地球化学分析和物源判别。南黄海NT2孔化学成分分布表现出一定的分层性,常微量元素组成的垂向变化可自上而下分为5层,常微量元素的R-型聚类分析表明初步可分成5个聚类,R-型因子分析反映常微量元素主要受4个因子控制。研究发现南黄海NT2孔沉积物物源主要为长江和黄河,NT2孔上部0~5.50和5.50~19.40m沉积物以长江源为主,19.40~27m沉积物以黄河源为主,底部54.60m以下沉积物以长江源为主,其间夹近28m厚的沉积物则以长江源为主。结果表明黄河在中更新世中晚期已开始对南黄海陆架沉积作用有明显的影响,长江从晚更新世早期到现代一直对南黄海陆架起着主要作用。
关键词:
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物源
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地球化学
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NT2孔
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南黄海
Abstract:
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.
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