Climatic Changes in the Middle and Late Period of the Last Glacial Period in Liaohua Section of Jiujiang, Jiangxi Province Recorded by End-Member Grain Size

• Main Authors: Li Shiqian, Li Zhiwen, Zhou Wanpeng, Du Dingding, Li Wubiao
• Format: Article in Journal/Newspaper
• Language: Chinese
• Published: Editorial Committee of Tropical Geography 2023
• Subjects: jiujiang city; liaohua section; middle and late last glacial; grain-size end-member analysis; monsoon evolution; climate change; Geography (General); G1-922; Greenland; Greenland ice core; ice core
• Online Access: https://doi.org/10.13284/j.cnki.rddl.003605; https://doaj.org/article/035b35153b6d48dfaaa754425b422d78

Late Quaternary aeolian sediment sequences are widely distributed in the Poyang Lake area and are good subjects for climate evolution research. However, previous studies have focused mainly on aeolian sediments and less on lacustrine facies and their overlapping accumulation with aeolian sands. Therefore, after field investigations in Shaling Mountain, Xingzi County, the Liaohua section was selected as the study area where we tested the geological age and grain size, analyzed the grain size results by end-member analysis model, and compared the end-member component content with the average grain size and standard deviation. Oxygen isotopes of stalagmites in YZ Cave, Chongqing, and Greenland ice core records were analyzed. We also discussed the climate change law in the middle and late periods of the last glacial period in this area to source basic data for the response of the last glacial deposits in the Poyang Lake area to the East Asian monsoon and even the whole world. The results show the following: 1) This section is composed of lake facies, ancient soil, dune sand, and other sedimentary facies. Combined with the dating results and deep-sea oxygen isotope records, a chronological-depth framework based on the piecewise sedimentation rate interpolation method was constructed. The dating results show that this profile was formed in the middle and late glacial stage (48.8-17.1 ka) and the grain size was mainly silt, medium sand, and fine sand. Clay was higher in the paleosol or lacustrine layer, and coarse sand had the highest volume fraction in the dune sand layer. 2) The end-member analysis model separates the granularity data into three different granularity end-members ( EM1, EM2, and EM3). The contents of different end-member components in different strata are obviously different. EM1 represents the end-member components of silt, and the peak values correspond to the development period of lacustrine facies and paleosol. EM2 and EM3 represent the end-member components of medium sand and coarse sand, ...