Off The Central And Western Holocene Environmental Changes

In the west part of Guanzhong Basin, there are some Holocene loess profiles with several layers of paleosol. It provides detailed information about environment change. So we select one profile with three paleosol in Co. Fufeng, west of Guanzhong Basin and another profile with one paleosol in Xi'an, middle of Guanzhong Basin.Pollen-analysis is often used in the research of pale-vegetation and pale-environment. The high resolving-ratio pollen analysis in Fufeng Profile reveals that the deciduous broad-leaved forest grew in the region of Guanzhong Basin during the Holocene Megathermal. The deciduous forest was mainly composed of Quercus,Curpressaceae and Anacardiaceae. According to pollen analysis, the vegetation succession during the Hobocene was reconstructed: desert steppe-deciduous forest of warm temperate zone-deciduous shrubs-deciduous forest of warm temperate zone-forest steppe.On the other hand, it is found that the Holocene paleosol(So) is really a kind of forest soil from the study of magnetic susceptibility, grain size, chemical components and soil micromorphology in Fufeng Profile and Xi'an Profile. Its type is luvic cinnamon soil without CaCO, illuvial horizon. Specially, Xi'an Pofile's section configuration is A-Bk-Cl(eluvial bess horizon)-Ck-C.On the basis of multiple analysis of vegetation, soil type, chemical components et.al, Hobocene environment change in the west region of Guanzhong Basin may be divided five stages.