Sediment Magnetism Characteristics and Its Climatic Environment Significance of Northeast Margin of Jianghan Plain

In order to reveal the sediment magnetism characteristics and its climatic environment evolution since Late Pleistocene of the Jianghan plain, we collected magnetic susceptibility samples from Macheng, the northeast margin of the Jianghan plain, for analysis. The results show that the mass susceptibility of magnetic materials in Macheng profile is relatively low(10.85×10^-8 m³·kg^-1 on average), and the variation range of mass susceptibility is narrow (5.76×10^-8-23.39×10^-8 m³·kg^-1). However, the variation range of frequency susceptibility is relatively wide (5.35%－50.35% and 24.71% on average), which shows that the content of SP (super paramagnetism) particulate is high. The cyclic wave characteristics of magnetic susceptibility and frequency magnetic susceptibility data suggest that the paleoclimate environment of this region could be divided into 7 evolution phases. According to the chronological data, it is concluded that the sedimentary environment of this region has undergone limnetic facies sedimentary stage, lacustrine sedimentary stage, swamp sedimentary stage in flood plain since Late Pleistocene, whereas the climate has undergone the phased variation of humid-dry-cold-warm-wet-dry-cool-dry-cold-humid-dry (drought) and cool, which is consistent with the global climate change characteristics since Late Pleistocene.