The Vegetation Chenges in Ulan Buh Desert Since the Last GLACIAL:POLLEN Evidence from Core WL10ZK-1

The paleo-vegetation changes of the Ulan Buh Desert since last Glacial are discussed according to the lithology,chronology and pollen analyses of the drill core WL10ZK-1.The high content of Typha pollen(up to 12%),and a quantity of Picea(up to 22.5%),Poaceae and Cyperaceae pollen from the bottom of drill core indicate that there was a lacustrine environment with steppe vegetation in the Ulan Buh Desert before 90 ka.Since 90 ka,xerophytic/halophyte herbs or shrubs such as Chenopodiaceae,Artemisia coupled with Tamaricaceae and Zygophyllaceae dominated the pollen from the middle of the drill core which indicates a desert vegetation environment occurred during the last glacial.During the phase of 8~7 ka,the UBD is dune-pond environment with steppe vegetation characterized by high percentage of Pinus and Artemisia.