Reconstructing chemical weathering, physical erosion and monsoon intensity since 25 Ma in the northern South China Sea: A review of competing proxies

CORC > 南海海洋研究所 > 中国科学院南海海洋研究所 > 中科院边缘海地质重点实验室

	Reconstructing chemical weathering, physical erosion and monsoon intensity since 25 Ma in the northern South China Sea: A review of competing proxies
	Clift, PD ; Wan, SM ; Blusztajn, J
刊名	EARTH-SCIENCE REVIEWS
	2014
卷号	130 页码:86-102
关键词	Monsoon Erosion Weathering Clay mineralogy Sediment geochemistry South China Sea
ISSN号	0012-8252
通讯作者	pclift@lsu.edu
中文摘要	Reconstructing the changing strength of the East Asian summer monsoon has been controversial because different proxies, many being indirect measures of rainfall, tell contrasting stories about how this has varied over long periods of geologic time. Here we present new Sr isotope, grain-size and clastic flux data and synthesize existing proxies to reconstruct changing chemical erosion in the northern South China Sea since the Oligocene, using the links between weathering rates and monsoon strength established in younger sediments as a way to infer intensity. Chemical proxies such as K/Rb, l(/Al and the Chemical Index of Alteration (CIA), together with clay proxies like kaolinite/(illite + chlorite) show a steady decline in alteration after a sharp fall following a maximum at the Mid Miocene Climatic Optimum (MMCO; 15.5-17.2 Ma), probably as a result of cooling global temperatures. In contrast, physical erosion proxies, including bulk Ti/Ca and clastic mass accumulation rates (MAR), show peaks at 21-23 Ma, similar to 19 Ma and 15.5-17.2 Ma, implying faster run-off in the absence of drainage capture. Rates increase again, likely driven by slightly increased run-off after 13 Ma, but decrease after 8 Ma, which is identified as a period of summer monsoon weakening. Sr isotope composition correlates with hematite/goethite and the spectral proxy CRAT to show stronger weathering linked to more monsoonal seasonality. These proxies argue for a strengthening of the East Asian Monsoon after 22-23 Ma, followed by an extended period of monsoon maximum between 18 and 10 Ma, then weakening. There is some suggestion that the summer monsoon may have strengthened since 3-4 Ma after reaching a minimum in the Pliocene. (C) 2014 Elsevier B.V. All rights reserved.
学科主题	Geology
收录类别	SCI
资助信息	China NSF [41076033]; JOI-USSAC; University of Aberdeen
原文出处	ELSEVIER SCIENCE BV
WOS记录号	WOS:000332431900004
公开日期	2014-12-11
内容类型	期刊论文
源URL	[http://ir.scsio.ac.cn/handle/344004/10640]
专题	南海海洋研究所_中科院边缘海地质重点实验室
推荐引用方式 GB/T 7714	Clift, PD,Wan, SM,Blusztajn, J. Reconstructing chemical weathering, physical erosion and monsoon intensity since 25 Ma in the northern South China Sea: A review of competing proxies[J]. EARTH-SCIENCE REVIEWS,2014,130:86-102.
APA	Clift, PD,Wan, SM,&Blusztajn, J.(2014).Reconstructing chemical weathering, physical erosion and monsoon intensity since 25 Ma in the northern South China Sea: A review of competing proxies.EARTH-SCIENCE REVIEWS,130,86-102.
MLA	Clift, PD,et al."Reconstructing chemical weathering, physical erosion and monsoon intensity since 25 Ma in the northern South China Sea: A review of competing proxies".EARTH-SCIENCE REVIEWS 130(2014):86-102.