运城盆地洪积平原全新世环境演变与侵蚀阶段研究

根据山西运城盆地中条山洪积扇全新世剖面的磁化率、粒度分析研究,揭示了全新世以来运城盆地的环境演变和面状流水侵蚀堆积阶段。研究结果表明运城盆地全新世早期气候较温和干燥;全新世中期气候温暖湿润;而全新世晚期气候比较干旱。由于全新世气候的波动变化,以及人类活动的影响,运城盆地洪积扇地表出现过4个比较明显的面状流水侵蚀-堆积作用阶段,时间分别在11500-11000a B.P.、3850~3300a B.P.、2200~2000a B.P和1300-800a B.P.。其中,11500-11000a B.P.间的侵蚀-搬运阶段是由气候变化引起,后三个阶段则是由气候变化和人类活动共同作用的结果,这为探索黄土高原侵蚀历史演变提供了新的途径。

Holocene Environment Change of Pedogenesis and Erosion phases on Pluvial-alluvial Fan in Yuncheng Basin, Shanxi Province

A Holocene soil profile was investigated on the Zhongtiaoshan Mountain pluvial-alluvial fan in Yuncheng basin,Shanxi province.From the analysis of soil magnetic susceptibility and grain size,the Holocene environmental change and erosional-depositional phases were revealed.In the early stage of Holocene,the climate became warm,the biological weathering pedogensis was beginning;in the middle stage of Holocene,the climate became warmer and wetter,the Holocene paleosoil(S_(0)) was formed,and in the late period of Holocene,the climate became dryer,the dust storms happened frequently,the aeolian loess(L_(0)) was accumulated and covered on the paleosoil(S_(0)).Because of the fluctuation and change of the Holocene climate the four sheet rainwash erosional-depositional phases happened approximately in 11500-11000a B.P.,3850~3300a B.P.,2200~2000a B.P.and 1300-800a B.P.in Yuncheng basin,which provided a new approach to study erosion history of Loess Plateau.