Environmental processes derived from peatland geochemistry since the last deglaciation in Dajiuhu, Shennongjia, central China

作者：Yuanping Li, Chunmei Ma, Bin Zhou, Anning Cui, Cheng Zhu, Run Huang, Chaogui Zheng · 发表于：Boreas · 年份：2016 · DOI：10.1111/bor.12168 · 被引用次数：22 · 研究领域：Geology and Paleoclimatology Research、Coastal wetland ecosystem dynamics、Geological formations and processes

The Dajiuhu mire deposit is a sensitive archive of palaeoenvironmental evolution in the East Asian monsoon region. The aim of this study of the elemental geochemistry of a sediment core from Dajiuhu was to improve our understanding of the geochemical behaviour of elements in peat deposits, as well as the environmental and climatic history of the East Asian monsoon region since the Late Pleistocene. We conducted a principal components analysis ( PCA ) on inorganic geochemical data obtained by ICP ‐ MS and XRFS from a sediment core spanning the last 16 ka. In addition, spectral analysis was applied to the PC 1 score profile to test periodicities. The PCA results suggest that variations in elemental concentrations in the Dajiuhu core are controlled by three main factors: input of inorganic mineral matter, effect of biological processes and a combination of changes in redox conditions and biological processes. Interpretation of the data suggests that monsoon precipitation increased, albeit with significant volatility, during the last deglaciation (16.0–11.3 cal. ka BP ). The early Holocene (11.3–9.4 cal. ka BP ) was a humid period, and was followed by monsoon deterioration in the early stages of the middle Holocene. A warm and wet climate dominated between 7.0 and 4.2 cal. ka BP , correlating with the Holocene Climatic Optimum. After a two‐step decrease in monsoon precipitation, beginning at 4.2 cal. ka BP , the climate became more arid until 0.9 cal. ka BP , after which humidity...