THE RESPONSE OF THE DEVELOPMENT OF FEN RIVER TO NEOTECTONIC MOVEMENT AND PALEOCLIMATE CHANGES SINCE LAST NON-GLACIATION STAGE

There have existed three accumulation terraces (T₃,T₂ and T₁) and an erosional one in Linfen Basin since last non glaciation stage (MIS₅).By the means of loess paleosol series and TL,we make out that these terraces occurred in 130kaBP,130kaBP~52kaBP,52kaBP and 9kaBP respectively.Normally,neotectonic movement and paleoclimate changes are two important factors influencing the development of the alluvial landform.Analyzing the characteristics of the sedimental structures of some sections in these terraces,we draw some conclusions:①It was the neotectonic uplift occurring in 130kaBP that resulted in the formation of T₃.②Because the weather became wet and warm during L₁ SS and S₀,and down erosion of Fen River strenghtened,the changes of paleoclimate during late Pleiocene contributed to the development of T₂ and T₁.③The occurrence of the erosional terrace shows there probably had some big landslides taking place in 130kaBP~52kaBP in Sanmeng Gorge,which blocked the Yellow River for a long time.