南昌市厚田剖面末次冰期风沙沉积揭示的冬季风演变及其影响因素  

Winter Monsoon Evolution and Its Influencing Factors Revealed by Aeolian Sand Deposition in the Houtian Section of Nanchang City During the Last Glacial Period

作　　者：孙丽 李志文 詹江振[3] 张慧娟 杜丁丁 李向洁 Sun Li;Li Zhiwen;Zhan Jiangzhen;Zhang Huijuan;Du Dingding;Li Xiangjie(School of Environmental and Chemical Engineering,Foshan University,Foshan 528000,Guangdong,China;State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,Shaanxi,China;School of Earth Sciences,East China University of Technology,Nanchang 330013,Jiangxi,China)

机构地区：[1]佛山科学技术学院环境与化学工程学院,广东佛山528000 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,陕西西安710061 [3]东华理工大学地球科学学院,江西南昌330013

出　　处：《地理科学》2022年第12期2218-2228,共11页Scientia Geographica Sinica

基　　金：国家自然科学基金项目(41571007、41201006);黄土与第四纪地质国家重点实验室开放基金(SKLLQG1212)资助。

摘　　要：以鄱阳湖南部的厚田剖面为例,构建了OSL年代框架,采用端元模型分析粒度组成,得出EM1代表粉砂端元组分,峰值对应于砂质古土壤;EM2与EM3代表中砂-粗砂端元组分,峰值对应于沙丘砂,其峰谷交替特征揭示了末次冰期万年尺度的季风演变规律。HTS4(77.0—57.1 ka B.P.)、HTS3b(49.7—36.8 ka B.P.)、HTS2(26.5—14.9 ka B.P.)主要发育沙丘砂,EM1和磁化率为谷值,EM2、EM3和CaCO3质量分数为峰值,指示了寒冷干燥大风的冬季风强盛期,分别对应于MIS4、MIS3b和MIS2阶段。HTS3c(57.1—49.7 ka B.P.)、HTS3a(36.8—26.5 ka B.P.)主要发育砂质古土壤,EM1和磁化率为峰值,EM2、EM3和CaCO3质量分数为谷值,指示了温暖湿润的冬季风减弱期,分别对应于MIS3c和MIS3a,这些事件同步于亚热带石笋、黄土高原黄土等载体揭示的变化规律,外在驱动因素是太阳辐射量变化,内部因素是季风强度和河水涨落引起的物源变化。Taking Houtian section(HTS)in the south of Poyang Lake as example,we construct the OSL chronological framework,and analyze the grain-size by the endmember model.Results show that endmember 1(EM1)represents the silt endmember component,its peak value corresponds to the sandy paleosols,EM2 and EM3 represent the medium sand-coarse sand endmember components,its peak value corresponds to the dune sand.These peak-valley alternating characteristics reveal the monsoon evolution and climate fluctuation law during the Last Glacial period on the ten-thousand-year scale.During the periods of HTS4(77.0-57.1 ka B.P.),HTS3b(49.7-36.8 ka B.P.),and HTS2(26.5-14.9 ka B.P.),which mainly developed dune sand,with the peak of EM2,EM3 and CaCO3 content,and valley of EM1 and magnetic susceptibility(MS),indicating a cold and strong winter-monsoon period,corresponding to Marine Isotope stage 4(MIS4),MIS3b and MIS2,respectively.During the periods of HTS3c(57.1-49.7 ka B.P.)and HTS3a(36.8-26.5 ka B.P.),which mainly developed sandy paleosols,with the valley of EM2,EM3 and CaCO3 content,and peak of EM1 and MS,indicating a warm and weakening winter-monsoon period,corresponding to MIS3c and MIS3a,respectively.These events are basically synchronized with climate changes recorded in the carriers such as cave stalagmites of subtropical China,loess from the Chinese Loess Plateau,etc.It is believed that the external driving factor is from the changes of solar radiation,and the internal factor is from the combined effect of monsoon intensity changes and the provenance changes caused by river-level fluctuation.

关 键 词：厚田剖面 末次冰期风沙沉积 粒度端元模型分析 季风演变 湖水涨落 

分 类 号：P532[天文地球—古生物学与地层学]