临汾盆地中更新世中晚期以来的演化历史及成因分析

第四纪中晚期以来临汾盆地中发育了五级冲湖积台地或阶地。地貌沉积阶段性发育的特点反映出临汾古湖在这一时期曾经历过多次收缩的变化。根据上覆冲湖积台地或阶地的最老黄土古土壤序列，我们发现在S8的早期（年龄0.75MaBP)，S5的早期（年龄0.50MaBP)和S1的早期（年龄0.13MaBP)，盆地中发生了三次大幅度的湖退；在L1SS开始发育时（年龄52kaBP),汾河发生了一次强烈下切，形成了T2阶地。从影响湖盆变化的因素分析，构造抬升是导致三次大幅度湖退的根本原因；气候变化是T2阶地的致因。

The Evolution and its Contributing Factors of Linfen Basin Since Middle Quaternary

Five steps of alluvial and lacustrine platforms or terraces have been developed in Linfen Basin since Middele Quaternary. This multi stage deposits during its development indicates that the ancient Linfen Lake has experienced several regressions since then. From the palaeosoil profile acquired from the overlying loess, the authors found that the forming of the layer S8 (date 0.75 MaBP), layer S5 (date MaBP) and layer S1 (date 0.13 MaBP) corresponds respectively with the three large scale regressions of the basin while L 1SS was developed at the time when the Fen River cut deeply and formed T2 terrace. We know that elimate was wet and warm when palaeo soil is developed, but dry and cold when loess accumulated. Therefore, the following conclusion can be drawed:It is the structural uplift that leads to the formation of the three lake teraces. The development of T2 is attributed to the change of palaeo climate during late pleistocene.