LATE QUATERNARY VARIATION OF THE ARIDITY INDEX IN THE BADAIN JARAN DESERT,INNER MONGOLIA,CHINA─A DEDUCTION FROM LANDSCAPE EVOLUTIONS

Palaeoclitalologists have faced for decades the challenge to obtain quantitative palaeoclimatic parameters for the arid and semiarid environrnent The landscape conception in the sense of climatic geomorphology can be used to bridge this gap. In the Badain Jaran Desert, geomorphological studies show that there are clear evidences for the shifting of morphodyndric zones. Comparing the former and present-day formation of landscapes indicates that the precipitation during the less arid periods was much larger than that of previously thought. This is confirmed by lake level changes both in the dune fields and in the marinal regions. Decreased aridity indexes of ca. 30 ka B.P. and 20 ka B.P. signal that the influence of westerlies on the arid region of northwestem China was presumably intensified at these times