Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Chemical Geology 257 (2008): 240-246, doi:10.1016/j.chemgeo.2008.10.002.
Sediments of the upper 28.2 meters of Ocean Drilling Program (ODP) Site 1145 from
the northern South China Sea (SCS) were analyzed for their geochemical composition. Most
of the major and trace elements exhibit significant fluctuations at glacial-interglacial scales,
implying a close relation with regional and global climate change. Al-normalized elemental
ratios can be subdivided into three principal components (PC). PC1 (e.g., Ca/Al, Ba/Al, Sr/Al)
displays significant glacial-interglacial variation and is related to paleoproductivity in the
northern SCS. PC2 (e.g., K/Al, Mg/Al, Rb/Al) is associated with the degree of chemical
weathering in the source regions and shows little glacial-interglacial variation. PC3 (e.g.,
Ti/Al, Zr/Al) reflects the relative contribution of coarse- and fine-grained materials in the
terrigenous components of the SCS sediments, likely associated with changes in sea level and
monsoon-induced fluvial input. Spectral analyses indicate that paleoproductivity (i.e., Ba/Al)
in the South China Sea lags Hulu/Sanbao speleothem δ18O record (a indicator of annual
average meteoric precipitation) by 102° and Indian summer monsoon (multi-proxy stack) by
23° at the precession band, indicating a close relationship with the Indian summer monsoon.
However, the chemical weathering degree in the source area (PC2) is not sensitive to
monsoon-related changes at the precession band during the last climatic cycle.
This study was supported by the NSFC to Y.B. Sun and the US NSF to D.W. Oppo (OCE 0502960) and S.C. Clemens (OCE 0352215).
South China Sea
Major and trace elements
East Asian monsoon
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