Aeolian Deposits on the Southeastern Margin of Tengger Desert and Desert Evolution during the Last 60 000 Years

The ancient aeolian sand and dust has been thought of as the indicator that can indicate the formation and evolution of the desert within the past time. The signals of the desert evolution were well preserved in the aeolian deposits on the margin of desert,so these records are effective to reconstruct the desert evolution pattern. Moreover,the variation of grain size of the aeolian deposits may be caused by the strength of the wind which might result in the extension of the desert. Hence,the particle distrbution of the different layers can reflect the desert extension during the different periods. \;The typical stratum profile, named Zhongwei Nanshan section,can stand for the facie of aeolian deposits on the southeastern margin of Tengger Desert. Through TL and \{\}\+\{14\}C dating samples and grain size analyses, the temporal sequence of Tengger Desert evolution was established, which combined with the particle distribution, the temporal and spatial pattern of the desert evolution over the past \{60 000\} years can be reached. Namely, The extent of Tengger Desert did not reach its current position during the period of 60~20 ka B.P., however, it seriously extended southeastward within 20~11 ka B.P.. The southeastern desert was fixed and its extent shrank from 8\^1 ka B.P. to 5\^2 ka B.P.. During the periods of 11~8\^1 ka B.P. and 5\^2~0 ka B.P., the desert extent was similar to the current.