Changes In Climatic Environment During The 38-11ka BP Recorded In The Sediments Of The Shihu Lake

During the late Marine Isotope Stage 3 transforming to 2,paleoclimate and paleoenvironment change strongly.There are some differences in climate and environment changes in different regions,especially in the mid lower reaches of the Yangtze River.Shijiu Lake is located in the Yangtze River Basin,between Jiangsu Province and Anhui Province.The climate is subtropical monsoon climate,affected by the East Asian monsoon,so it is one of the ideal places to study the paleoclimate and paleoenvironment.This paper select SJH2 core as the object of study.Set up a high-resolution chronology by AMS14C dating method and linear interpolation.We have reconstruct the climate and environment evolving process during 38-11.4ka BP in Shijiu Lake area by environmental proxies,such as grain size,magnetic susceptibility,geochemical elements and chroma,etc.The process can be divided into three stages:(1)39-28.9ka BP,the stage corresponds to the later Marine Isotope Stages 3 when the climate is warm-humid.(2)28.9-17.2ka BP,the stage is the equivalent of the early-mid Marine Isotope Stages 2 with the cold-dry climate.The later(23-17.2ka BP)is colder than the earlier(28.9-23ka BP).(3)17.2-11.4ka BP,The stage is equivalent to later Marine Isotope Stages 2 as the climate of this stage is transfroming cold-dry to warm-humid.In this paper,the<4 ?m grain and lightness of Shijiu Lake core consistent with the South China Sea median diameter(MD)curve,Jingyuan Loess median grain size(MGS)curve and Nanjing Tangshan Hulu Cave Stalagmite isotope curve in 38-11.4ka,which illustrates climate in Shijiu Lake is consistent with other places in earth.At the same time,there are differences in fluctuating frequence and special events.The differences indicate climate is regional characteristics in Shijiu Lake area.