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通过对西藏海拔最高、面积最大湖泊—纳木错周缘湖相沉积、湖岸堤的野外调查和湖岸阶地的水准测量,发现在纳木错沿岸拔湖48m以下,发育有6级湖岸阶地,拔湖48～139.2m发育有高位湖相沉积。湖相沉积物的同位素测年结果表明,纳木错湖泊发育与藏北高原东南部古大湖演化可划分为3个阶段:①116～37kaB.P.间的古大湖期;②37～30kaB.P.间的外流湖期;③30kaB.P.以来的纳木错期。根据纳木错晚更新世以来湖相沉积中粘土矿物的X光衍射分析结果,以及采用比值法、高岭石法和衍射峰法的研究,探讨了粘土矿物所显示的环境变化信息。粘土矿物成分变化表明,该区已具备了寒温带干旱、半干旱区的气候环境特征。为研究青藏高原的湖泊演化、气候变化、古地理变迁及其隆升过程等提供了新资料。
Through the survey of the lakes of the highest elevation, the largest lake in the country, the lake sediments of the Nam Co fault, the field survey of the lakeshore banks and the leveling survey of lakeshore terraces, it is found that there are 6 lakeshore terraces 48 ~ 139.2m Development of high lacustrine deposits. The isotopic dating of the lacustrine sediments shows that the development of the Nam Co Lake and the evolution of the Paleo-lakes in the southeastern Tibet Plateau can be divided into three stages: (1) the Great Paleo-lacustrine period between116 and 37 kaB.P; (ii) between37 and 30 kaB.P. Outflow lake period; ③30kaB.P. Since the Namtso period. According to the results of X-ray diffraction analysis of clay minerals in lacustrine sediments since the Late Pleistocene in Namco, and using the ratio method, kaolinite method and diffraction peak method, the information of environmental changes revealed by clay minerals is discussed. The change of clay mineral composition shows that the region has the climatic and environmental characteristics of arid and semi-arid regions in the cold temperate zone. It provides new information for studying the evolution of the lake in Qinghai-Tibet Plateau, climate change, palaeogeographic change and its uplifting process.