河西走廊民乐盆地晚更新世以来的气候变迁

Climate changes during the Late Pleistocene of Minle basin in Hexi corridor

研究区属于张掖民乐盆地,在河西走廊的中间位置,是北祁连地槽褶皱系的山前断陷盆地。本文以冰沟台黄土剖面为研究对象,通过对沉积物的光释光年代、粒度、磁化率等进行研究,揭示了该地区自晚更新世末次冰期以来的气候变化的四个阶段。研究结果表明该地区晚更新世末次冰期经历了湿暖-干冷三个气候旋回,全新世主要经历了干冷向暖湿的气候转变,与古里雅冰芯氧同位素的气候旋回特征吻合。本文相对完整地反映了民乐盆地末次冰期以来气候波动变化特征,特别是为本区晚更新世以来的气候环境变化的研究提供了依据。

The study area belongs to the Minle basin in Zhangye.It is the middle position of the Hexi corridor and it is a foreland basin of the northern Qilian geosyncline fold system.In this paper,the loess section in Binggoutai is taken as the research object.Based on the analyses of sediment,OSL dating,grain size,magnetic susceptibility of loess section in Binggoutai,this paper reconstructs the history of climate evolution during the Late Pleistocene.It is indicated that Minle basin experienced warm-wet and dry-cold climates in the Late Pleistocene.Moreover,it is accorded with climate characteristics of the Last glaciation.Meanwhile,it experienced the evolutions of climate the dry-cold and warm-wet in the Holocene.Therefore,this paper reflects the evolutions of climate in the Minle basin during the Late Pleistocene.Especially,it also provides the basis for Hexi corridor＇s climatic and environmental evolutions since the Late Pleistocene.