A Preliminary investigation on the Vegetational and Climatic Changes Since 11, 000 Years in Qinghai Lake An Analysis Based on Palynology in Core QH85-14C MIS3b vegetation and climate changes based on pollen and charcoal on Qianxi Plateau New High Resolution Pollen Records from Two Lakes in Xizang (Tibet) Implication of Paleovegetational Changes in Diaojiao Lake, Inner Mongolia