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本文采用遥感影像分析和差分GPS方法精确测量各级湖岸堤高程,通过OSL定年技术对湖滨沉积物进行年代测定,重建湖泊演化的时空分布格局和环境变化历史。通过大范围的野外调查和测试,结果表明:在吉兰泰盐湖周围存在海拔高度1080~1070m,1060m,1050m,1044m和1035m的5级湖岸堤。在吉兰泰东北70km处乌兰布和沙漠腹地贺日木西尼也存在1080m的古湖岸堤和海拔高度1052m到1035m的长达11km的古沙嘴。各级湖岸堤沉积物由湖滨砂或湖滨砂砾石组成,含有蓝蚬等贝壳体,这些证据是吉兰泰古湖存在和湖面波动的重要标志。通过1080m湖岸堤沉积物的OSL年代测定,确认在MIS 3阶段的60ka B.P.前后发育吉兰泰古大湖,此时湖水向东延伸至乌兰布和沙漠腹地,水深达到60m。根据贺日木西尼湖岸堤高程和分布特征来推断,此时的吉兰泰古湖可能与河套古湖产生水源联系。吉兰泰古大湖形成和演化过程,受到区域气候、黄河(内蒙古段)演化和河套古湖的演变以及区域构造运动等诸多因素的影响,需要进一步研究。
In this paper, remote sensing image analysis and differential GPS method are used to accurately measure the elevation of lake bank embankments. The sediment ages of lakeside are determined by OSL dating technique, and the temporal and spatial distribution of lake evolution and the history of environmental changes are reconstructed. Through a large field investigation and testing, the results show that there are 5-level lake banks with 1080 ~ 1070m, 1060m, 1050m, 1044m and 1035m above the Jilantai salt lake. At about 70km northeast of Jutairi, in Helanmuhe, the hinterland of Ulanbuh Desert, 1080m ancient lake bank and an 11km long Gushazui at an altitude of 1052m to 1035m are also present. Sediments at all levels of the lake bank are composed of lakeshore sand or lakeshore sand and gravel, containing shells such as bluegrass. These evidences are an important indicator of the existence of the ancient Jilantai Lake and the fluctuation of the lake surface. Based on the OSL dating of 1080m lakebank sediments, it was confirmed that the ancient Gujarat Lake was developed before and after 60ka B.P. in MIS 3, and the lake water extends eastward to the hinterland of Ulan Buh and the desert at a depth of 60m. According to the Hexi Mui Nei dike embankment elevation and distribution characteristics to infer that the ancient Jilantai Lake at this time may be associated with the ancient river lacustrine source. The formation and evolution of the Great Great Lake in the Jilantai area need further study due to the influences of the regional climate, the evolution of the Yellow River (Inner Mongolia) and the evolution of the Hetao Ancient Lake, as well as regional tectonic movements.