晚更新世以来内蒙古哈素海钻孔地层记录及其年龄

“河套古大湖”对于研究区域环境及气候演化具有重要的意义，然而，其形成与消亡的时代仍存在争议。依托于哈素海西南岸边获取的HSH钻孔，采用AMS14C、OSL测年方法确定了沉积物年代，结合岩心的岩性、沉积结构等特征，分析了哈素海的演化历史，并探讨了河套古大湖存亡的时期。结果表明，哈素海地区晚更新世以来的沉积环境主要经历了以下转变过程：150~70 ka为较稳定的湖泊，70~55 ka湖泊水位下降，为滨湖相沉积，55~27 ka为湖沼沉积，27~0 ka为滨湖相沉积。根据哈素海的沉积演化历史，结合河套盆地相关研究成果，认为河套古大湖早在150~110 ka就已形成，其后水位下降，直至55 ka之后，萎缩消亡，河套盆地局部地区形成湖沼沉积，但已不再是统一的大湖。研究结果对于深入探讨河套盆地演化历史乃至黄河的变迁具有重要意义。

Stratigraphy and chronology of a Late Pleistocene sediment core from Hasuhai Lake in Inner Mongolia

The "mega-paleolake" in Hetao Basin has great significance for the study of the evolution of the local environment and climate, but its time of the formation and disappearance remains controversial.Based on the HSH drilling data obtained from the southwest coast of Hasuhai lake, the ages of the sediments were determined by AMS 14C and OSL dating methods.Combined with the zharacteristies of lithology and sedimentary structure, the evolution history of Hasuhai lake was analyzed, and the survival period of Hetao ancient lake was discussed.The results show that the sedimentary environment in the Hasuhai Lake area has undergone the following transformation since the Late Pleistocene.It was a relatively stable lake during 150~70 ka, and transformed into lakeside facies in 70~55 ka due to the decrease of the water level.It turned into swamp in 55~27 ka, and transformed into lakeside facies again during 27~0 ka with the rise of the water level.According to this study, combined with the other research results, it is believed that the "mega-paleolake"in Hetao Basin was formed as early as 150~110 ka.It shrank and even died out during 110~55 ka.After that, although some regions in Hetao Basin were lake or swamp, it was no longer a unified mega-lake.The result is significant for the further study of the environmental changes in Hetao Basin.