CLIMATE VARIABILITY AND EOLIAN DEPOSITS SINCE ABOUT 8 500 YEARS AGO IN XI'AN

According to field investigation, soil thickness determination, indoor grain size analysis, CaCO₃ content analysis and rnicrostructure identification, we know changes in climate and eolian deposits since about 8 500 years ago in Xi'an. The data show that Holocene climate,compared with that in the first stage of last interglacial, had more frequent changes and variations. Compared with the last glacial which was 75 000-10 000 years ago, eolian deposits and sand storm activity since 3 100 aBP have been much stron-ger. The reason for this is the strong dry climate. The analysis of the development of loess in Holocene indicates that the loess in the Loess Plateau can develop under different climate conditions such as in glaci-ation, in interglacial stage, in winter monsoon and in summer monsoon whose activities were as strong as the winter monsoon behavior. According to the climate change forecast, future sand storm activity should be strengthened. Holocene climate variability will bring uncertainty to the long-term climate change pre-diction in future. Furthur study about the characteristics of climate variability in Holocene is of very important significance for long-term climate change prediction in future.