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Palynological investigations on lacustrine sediment samples revealed a general dominance of open Artemisia-Chenopodiaceae vegetation in the Palaeo-Gaxun-Nur-Basin (Inner Mongolia) between 5250 and 3500 cal. aBP. Riverside woods (Hippophae, Populus) developed between 3500-3250 cal. aBP and reflect moister growing conditions. During the following moist-dry transition pronounced cooling occurred around 3000 cal. aBP, in upper elevations favouring the spread of montane woods (Picea, Betula). Aridity strongly increased from 2900 to 2700 cal. aBP. The recorded vegetational and environmental changes after 3500 cal. aBP can be correlated with glacier advances in the mountains and with a humid phase in the Tengger Shamo followed by desertification.