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Compositions of foraminifera-rich turbidite sediments from the Shenhu area on the northern slope of the South China Sea: Implication for the presence of deep water bottom currents
Li, N; Feng, D; Chen, LY; Wang, HB; Chen, DF; liniu@mail.sysu.edu.cn; feng@scsio.ac.cn
2017
Source PublicationJOURNAL OF ASIAN EARTH SCIENCES
Volume138Pages:148-160
AbstractThe sediments in gravity core DH-1, collected from Shenhu area on the northern slope of the South China Sea, are composed of two dark grey clay silt layers (A(1) and A(3)) and two foraminifera-rich layers (A(2) and A(4)) (A(1) is the top layer and A(4) is the bottom layer). Major and trace metal contents, along with grain size and mineralogic data suggest that these silt layers represent background hemipelagic sedimentation. Unlike silt layers, the intervening foraminifera-rich layerA(4) exhibits a fining-upward trend, is distal turbidite. Grain size CM diagram and the sharp contacts between the foraminifera-rich layer A(2) and the upper and lower layers suggest layer A(2) is the result of depositional interaction between turbidite and bottom currents. AMS 14C dating of planktonic foraminifera indicate the age of the turbidite in A(2) is between15.3 ka and 22.6 ka. We hypothesize that turbidite formation in this period was related to the increase supply of terrigenous matter since the Last Glacial Maximum. The rapid deposition of each turbidite led to reduced rates of oxygen diffusion into the sediment, allowing anoxic conditions develop in sediments and fostering U enrichment (> 3.1 mu g/g) in foraminifera-rich layer A(4b). In contrast, decrease concentration of U and U/Mo ratios in foraminifera-rich layerA(2), which is possibly due to U remobilization as a consequence of downward penetration of the oxidation front from the oxygen rich bottom currents. These new data suggest that authigenic U was quite sensitive to the inflow of bottom currents, and U/Mo ratios may indicate the depositional environmental change in relation to the bottom current action on the turbidite. (C) 2017 Elsevier Ltd. All rights reserved.
Department[Li, Niu] Sun Yat Sen Univ, Sch Earth Sci & Engn, Guangzhou 510275, Guangdong, Peoples R China; [Li, Niu; Feng, Dong] Chinese Acad Sci, CAS Key Lab Marginal Sea Geol, South China Sea Inst Oceanol, Guangzhou 510301, Guangdong, Peoples R China; [Chen, Linying; Chen, Duofu] Shanghai Ocean Univ, Coll Marine Sci, Shanghai Engn Res Ctr Hadal Sci & Technol, Shanghai 201306, Peoples R China; [Wang, Hongbin] Guangzhou Marine Geol Survey, Guangzhou 510740, Guangdong, Peoples R China
KeywordTrace Metals Turbidites Redox Condition South China Sea
Funding ProjectMSG
Document Type期刊论文
Identifierhttp://ir.scsio.ac.cn/handle/344004/16493
Collection中科院边缘海地质重点实验室
Corresponding Authorliniu@mail.sysu.edu.cn; feng@scsio.ac.cn
Recommended Citation
GB/T 7714
Li, N,Feng, D,Chen, LY,et al. Compositions of foraminifera-rich turbidite sediments from the Shenhu area on the northern slope of the South China Sea: Implication for the presence of deep water bottom currents[J]. JOURNAL OF ASIAN EARTH SCIENCES,2017,138:148-160.
APA Li, N.,Feng, D.,Chen, LY.,Wang, HB.,Chen, DF.,...&feng@scsio.ac.cn.(2017).Compositions of foraminifera-rich turbidite sediments from the Shenhu area on the northern slope of the South China Sea: Implication for the presence of deep water bottom currents.JOURNAL OF ASIAN EARTH SCIENCES,138,148-160.
MLA Li, N,et al."Compositions of foraminifera-rich turbidite sediments from the Shenhu area on the northern slope of the South China Sea: Implication for the presence of deep water bottom currents".JOURNAL OF ASIAN EARTH SCIENCES 138(2017):148-160.
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