Sedimentary characteristics of terrigenous debris at site MD05-2905 in the northeastern part of the South China Sea since 36 ka and evolution of the East Asian monsoon |
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| Authors: | Wenguang Yang Hongbo Zheng Ke Wang Xin Xie Guocheng Chen and Xi Mei |
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| Institution: | (1) State Key Laboratory of Marine Geology, Tongji University, Shanghai, 200092, China;(2) Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu, 610059, China |
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| Abstract: | Sediments with high sedimentation rate at site MD05-2905 in the Northeastern slope of the South China Sea provide unique materials
for a high-resolution study on the paleoenvironment. Based on precise dating of AMS 14C, grain size analysis of terrigenous debris at core MD05-2905 was conducted after organic matter, biological carbonate and
biogenic opal were removed. The results show that 15.5–63.5 μm coarse grain size ingredients may indicate East Asian winter
monsoon changes and that 2–9 μm fine grain size ingredients may be used as a proxy of evolution of the East Asian summer monsoon.
The results of grain size analysis, which suggest East Asian monsoon intensity, reveal that a winter monsoon dominated the
glacial regime and a summer monsoon dominated the Holocene regime. It was also shown that the summer monsoon increased gradually,
experienced several abrupt changes and reached a culmination in the early Holocene (11200–8500 a B.P.) since 36 ka. Controlled
by precession periodicity, it may be related with the amount of solar radiation at the highest stage, which needs further
study.
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Translated from Advances in Earth Science, 2007, 22(10): 1012–1018 译自: 地球科学进展] |
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| Keywords: | terrigenous debris grain size analysis East Asian monsoon Holocene South China Sea MD05-2905 |
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