PLEISTOCENE ENVIRONMENTAL MEGAEVOLUTION AS INDICATED BY THE SPOROPOLLEN FLORAS IN CHINA

By an analysis of the sporopllen time sequences from samples of 38 sections, a discussion of the vegetational and environmental megaevolution in China during the time of 1.6MaBP~0.8MaBP was made, with the result that we have 2 zones of the sporopollen assemblages and 2 palynoclimate events. It is pointed out that it was the period of the worst environment in the pleistocene, during which vegetation was very sparse, with dominantly forest-steppe and steppe in northern China, desert or desert-steppe in northwestern China and forest and shrub-steppe in southern China. It has been shown that the climate was then cold and dry, with a of 15~17℃ temperature drop and decrease En precipitation of 300~500mm. As a result no reappearance of subtropical plant has since occurrred in North China and further north, but an initial form of the present vegetation cover. There after there was a more frequent and larger flora fluctuation. The change of spruce pollen in Qaidam Basin shows that the Qinghai-Tibetan Plateau had then been uplifted to a height that could cause a transformation of the vegetation.