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对腾格里沙漠古湖泊沉积和地貌的考察及对典型代表剖面初步研究结果表明，一个连续而巨大的淡水湖泊高水位形成于距今３．９～３．６万年前．在距今３．３～２．３万年期间，腾格里沙漠西北部曾存在一面积至少达１６２００ｋｍ２、水深２５ｍ（白碱湖，最大水深超过６０ｍ，分布于大海子一带）的淡水湖泊．大量的瓣鳃类、腹足类化石及介形类化石组合的存在表明该时期湖泊水温不低于１０℃，由此把该时期的湖泊暂且称“腾格里大湖”（ＭｅｇａｌａｋｅＴｅｎｇｇｅｒ）
The investigation of the sedimentation and topography of the ancient lakes in the Tengger Desert and the preliminary study of the typical representative sections show that a continuous and huge freshwater lake formed at a height of 3.9 to 36,000 years ago. In the period of 3.3 ~ 2.3 million years ago, there existed a freshwater lake in the northwestern Tengger Desert with an area of at least 16200km2 and a water depth of 25m (Baekji Lake, the maximum depth of more than 60m, distributed in the Dahaizi area). The existence of a large number of flap gill, gastropod fossil and ostracod assemblages indicates that the lake water temperature during this period is not lower than 10 ℃, thus the lake in this period is called “Megalake Tengger”