AEOLIAN DEPOSIT EVIDENCE FOR FORMATION AND EVOLUTION OF THE TENGGER DESERT IN THE NORTH OF CHINA SINCE EARLY PLEISTOCENE

Analyses of paleomagnetic polarity reversals, magnetic susceptibility and grain size on the loess-paleosol sequence of Duanxian section, about 223 m thick, at a pediment of Longxi basin lying to the west of Liupan Mountain,show that this sequence contains most of the stratigraphic units recorded in the standard loess-paleosol section in the China Loess Plateau over the past 1.8 MaBP. Using sand particle percentage (>63 μm%) of the eolian sequence as a proxy indicator of desert extent and aridity in the dust source regions,the authors preliminarily found that during the past 1.8 Ma, there were two important climatic events indicating the advance of the Tengger Desert. The events occurred around 1.1 and 0.8 MaBP, respectively. The stepwise advance and changes of the Tengger Desert may have a close relation with the increase in global ice volume and monsoon change and uplift of the Tibetan Plateau in the late Cenozoic.