THE RESPONSE OF THE DEVELOPMENT OF FEN RIVER TO NEOTECTONIC MOVEMENT AND PALEOCLIMATE CHANGES SINCE LAST NON-GLACIATION STAGE
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摘要: 野外调查发现,末次间冰期(MIS5)以来临汾盆地普遍发育了一级冲湖积台地(T3)、一级湖蚀台地、两级堆积阶地(T2、T1).利用黄土磁化率地层定年法、TL测年法,确定这些台地或阶地的年龄分别为130kaBP、130kaBP~52kaBP、52kaBP和9kaBP.分析构造和气候因素对河湖地貌发育的影响规律,得出T3台地的形成是130kaBP的区域构造抬升的结果;T2、T1阶地的出现是河流响应晚更新世以来气候变化的产物;湖蚀台地的存在反映了汾河下游黄河三门峡河段可能曾因古崩塌滑坡而被堵塞过。Abstract: 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.
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Key words:
- Linfen Basin /
- TL /
- aging by susceptibility /
- climatic terrace /
- tectonic terrace
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