Sedimentary responses to the Pleistocene climatic variations recorded in the South China Sea

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• 作者：Sé ; bastien Boulay ; Christophe Colin ; Alain Trentesaux ; Sté ; phane Clain ; Zhifei Liu ; Christine Lauer-Leredde
• 关键词：South China Sea ; Grain size ; End-members modelling ; East Asian monsoon ; Mid-Pleistocene Transition
• 刊名：Quaternary Research
• 出版年：2007
• 出版时间：July 2007
• 年：2007
• 卷：68
• 期：1
• 页码：162-172
• 全文大小：1298 K

文摘

Grain-size analyses, coupled with end-member modelling, have been performed on the terrigenous fraction of two Leg 184 Ocean Drilling Program sites (1144 and 1146) from the South China Sea. The grain-size distributions over the last 1.8 Ma enable a new interpretation of their connections to sea-level variations and East Asian monsoon strength. Previous investigations in this area have associated grain-size variability with enhanced eolian input during glacial stages. End-member modelling downgrades the importance of this eolian contribution and indicates that the sediments can be described as a mixture of three end-members: fluvial mud inputs, shelf reworking and river mouth migration. Grain-size variations in the Pleistocene section of the cores indicate a multiple-stage evolution: (i) from 1.8 to 1.25 Ma, the downcore grain-size variations are low but show a correspondence between monsoon rainfall intensity and the fine grain-sized fluvial inputs; no link with sea-level variations is noticeable; (ii) from 1.25 to 0.9 Ma, there is an increase (decrease) in the intermediate (fine) end-member ( 100 kyr cycle) that is associated with the onset of a stronger summer monsoon and modest shelf reworking; (iii) from 0.9 to 0 Ma the grain-size record is dominated by global sea-level variations; each glacial stage is associated with extensive shelf reworking and conveyance of coarse particles to the basin.