Research of Mid Holocene environment in Xi′an region

Holocene paleosol have been called as loessial soil since its existence was determined. Recently, some researchers determined Holocene paleosol around Xi′an as luvic phaeozem or brown earth. However, these opinion about the type of paleosol are not uniform. In this paper, the author discusses Holocene paleosol, vegetation type and climate by the materials of contents of CaCO 3, Fe 2O 3 and Al 2O 3, soil micro morphology and sporo pollen analysis. These materials reveal that Holocene paleosol around Xi′an formed during Megathermal is luvic cinnamon soil developing in warm and humid climate but not developing in subarid climate. During the forming time of Holocene paleosol, vegetation type of this area would be deciduous broad leaved forest which mainly consist of Quercus according to pollen analysis and the existence of dense root cavity at the bottom of Holocene paleosol of which depth of distribution is more than 2m. At that time mean annual rainfall in Xi′an would be 750 mm or more and mean annual temperature would be about 14℃.