GDGTs Records And Climate Reconstruction Since The Little Ice Age In Arxan,Inner Mongolia

The global temperature has been rising,and the instability of climate and environment has increased since the Little Ice Age.Severely natural disasters such as drought and flood disasters,ozone layer hole and so on occur frequently.During the Little Ice Age,there were secondary cold and warm fluctuations,which had a profound impact on human production and life.It is an ideal place to reconstruct the past climate change which can respond to climate change sensitively from Luming lake,Arxan region,Northeast China.As an important information carrier of continental climate and environmental change,lake sediments have irreplaceable advantages in studying global change and regional response.This study presented an independent growth temperature(May-September)record based on br GDGTs from Luming lake,Arxan region,Northeast China.The main conclusions are as follows:(1)The corrected age of the plant debris in the sediments of Luming lake uses by AMS ¹⁴C and ²¹⁰Pb?¹³⁷Cs;The bottom age of the core is about 1700 AD.(2)There are probably three climatic evolution stages in the Arxan region since the Little Ice Age by the reconstruction results of brgdgts in the sediments.From the 18th century to the beginning of the 20th century,the growth season temperature in study area showed a fluctuating trend.From the beginning of the 20th century to the 1990s,it continues to drop from about 14.0? to 12.0?,which indicates that the cooling responds well to the increasing frequency of large-scale volcanic eruptions.After the 1990s,it shows an obvious warming trend.The results show that the average growth season temperature in the study area is?13.8?since the Little Ice Age,and the range is?3.0?.(3)The results are similar to those of the tree-ring reconstruction in Arxan region from May to July and it is also similar to Long-chain alkenones(LCAs)are reconstruction from maar lakes in the Longgang volcanic filed.(4)Through comparison with other research results,it is similar that the temperature changes in the growing season in other regions by ther environmental proxy or in the sme region since the Little Ice Age.And there is a good correspondence between large-scale volcanic eruptions and regional cooling events.