The Holocene loess-paleosol sequence features and its significance of Nansicun profile in Xianyang city

Through the analysis about soil layer,magnetic susceptibility,particle size,pH value,calcium carbonate content and some chemical element determination of Holocene NSC profile in the middle reaches of the Weihe River,it was found that the magnetic susceptibility and clay content of Malan loess layer L1 are the lowest in the whole section,and are the highest in paleosol S0.And they are moderate in transition layer Lt and modern soil layer L0.pH value,calcium carbonate content and some element parameters have a good relationship with magnetic susceptibility,and it suggested that in the early of Holocene,the climate was mild and dry,the rainfall was little,and the biochemical weathering was weak.Entering the Holocene warm period,the climate became warm and humid,the rainfall increased,Loess accumulation rate decreased,the chemical weathering enhanced and pedogenesis was distinct.In the late of Holocene,climate became deteriorating and drying,pedogenesis was abated and dust accumulation was enhanced.