Climatic and environmental changes since 2 kaBP by End Member Modeling analysis on grain size data from a peat core of Yuhua Mountain, Jiangxi Province

Based on the AMS¹⁴C dating of a peat core from Mt Yuhua in Jiangxi Province, China, we explore how grain size varies in response to climate changes. We then reconstruct climate change since 2 000 aBP through grain size analysis, grade-standard deviation method, and end-member model. Our results show that the sediments in the peatland of Mt Yuhua are mainly consisting of fine sand (4～16 μm) and coarse silt (16～64 μm). Three end-members EM1, EM2, and EM3 represent, respectively, fine components transported by hydrodynamics, soil-forming components, and components that reflect abrupt climate changes. Grade-standard deviation indicates a range of sensitive components between 10.473 and 16.535 μm. Our reconstruction shows, first and foremost, an increase in precipitation between AD 1−300, Which was fellowed by a generally dry condition in AD 300−500 and a wet condition in AD 500−650, the latter period probably witnessed fewer climate fluctuations and floods. Despite an overall dry condition, climate fluctuated greatly in AD 650−900, and, while AD 900−1400 was relatively humid, the climate was not stable for a brief duration of 100 years. The Little Ice Age (LIA), spanning over 500 hundred years from AD 1400 to 1800, can be roughly divided into three stages, each governed by a wet, dry, and wet condition. The palaoclimatic reconstruction in this study is proved to be reliable when compared with δ¹⁸O data collected from Dongge cave and the humidity index of Jiangnan region.