1. Role of late glacial to mid-Holocene climate in catchment weathering in the central Tibetan Plateau
- Author
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Jin, Zhang-Dong, Wu, Yanhong, Zhang, Xiaohui, and Wang, Sumin
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CLIMATE change ,LAKE sediments ,CLIMATOLOGY ,GLACIAL climates - Abstract
Abstract: The lightness (L*) and concentrations of Rb, Sr and organic carbon (C
org ) have been measured in the age-constrained lake sediment cores recovered from Co Ngoin in the central Tibetan Plateau. Dissolved Sr flux is a dominant control on the variation of Rb/Sr ratios in the sediments. Variations in color and geochemical proxies of Co Ngoin sediments display a continuous history of late glacial to mid-Holocene chemical versus physical weathering intensity in response to past climatic changes between approximately 13,500 and 4500 cal yr B.P. A lower chemical weathering under a late glacial climate was followed by a higher weathering during the Holocene Optimum. Weathering intensity in the central Tibetan Plateau catchment also responds to well-known climatic events, such as the Younger Dryas (YD), and possibly the Holocene Event 5 (HE-5). Although there are differences in time or duration of the climatic events, many of the well-known late glacial to mid-Holocene events occurred in high-elevation Co Ngoin where atmospheric circulation might play a hemispherical role in climatic forcing. The sediment hiatus since c. 420014 C yr B.P. in the Co Ngoin indicates a period of desiccation that was probably associated with a sharp decrease in summer monsoon strength. Our lascustrine results not only imply catchment weathering variations in response to late glacial to mid-Holocene climatic conditions in the central plateau, but also provide further evidence for global connections between regional climates. [Copyright &y& Elsevier]- Published
- 2005
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