关键词: 热释光测年, 毛乌素沙漠, 干旱事件

Abstract: Thermoluminescence technique had been used to date the age of the sand-loess-palaeosol series of Yulin,Shanxi Province.Our results indicate that there are three sand layers intercalated in the last glacial sediments,suggesting the recurring of three arid episodes during the last glacial time.The latest arid period occurred between 12 and <27 ka B.P.,nearly coeval with the last glacial maximum,and could be correlated with stage 2 of marine oxygen isotope records.The second arid interval,with a TL age around 48 ka B.P.,could be correlated with part of stage 3.The earliest arid episode with TL age between 55 and <75 ka B.P.corresponds to stage 4.Our results also indicated that although the arid evidence,corresponding to stage 2 and stage 4,can be found in other regions of the world,the arid episode interbedded in stage 3 can be only well documented by the sand-loess-soil profiles of Yulin.Thus,it reflect the high sensitivity of the Chinese desert-loess transitional zone to the Quaternary climatic changes.In addition,the TL results suggest that the last glacial sediments consist of alternatively depositing of sand and loess,and the last interglacial sediments consist of loess beds and palaeosols,these do reflect the climate is not only characterized by the glacial/interglacial stages,but also the within stage climatic changes.The existence of sand-loess-soil sequence reflect in some way the mobile dune sands of Mu Us Desert were only restricted to some periods of Quaternary,the extension and stabilization of Mu Us Desert are the results of cyclical climatic changes.

Key words: Thermoluminescence dating, Mu Us Desert, Arid episode