Holocene aeolian loess and pedogenic environmental change in the upper-reaches of the Huaihe River

On the basis of field exploration and research,the content and changes of constant element oxides have been measured by XRF at the YPC loess-paleosol profile,Yuzhou County,Henan Province.Comparing with magnetic susceptibility,the content of clay grain and CaCO3,we found that the content of Al2O3,Fe2O3,K2O and MgO varied regularly in the Holocene Aeolian loess-paleosol profile,that is,the content of these oxides reached the highest in the paleosol(S0),moderate in the topsoil(MS),and the lowest in the loess(L1、Lt、L0).Na2O eluviated in the paleosol but congregated relatively in the loess.The content of these oxides correlated with magnetic susceptibility remarkably,which showed that the transference of these constant elements was controlled mainly by the Holocene climate.Deep analysis showed that the Holocene loess in the upper reaches of Huaihe River was wind blown dust sediment which came from the Yellow River inundant alluvial deposition and then reconstructed by Aeolian sand and dust storms aggradations.It indicated that the climate was warm and humid in the stage of the paleosol and the modern topsoil formation,the pedogenesis and secondary argillification was stronger although dust storms still occurred occasionally.In the stage of the loess accumulation,the climate was arid and cold,the vegetation was sparse in the lower-reaches of Yellow River inundant plain,the intensity of wind power and dust-fall was stronger,so the efflorescent pedogenic effect was exceedingly weak.The above revealed the Holocene pedogenic environmental change in the upper reaches of the Huaihe River.The results would help to understand the regional response to global change in the upper reaches of the Huaihe River in semi-humid zone.