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晚更新世晚期 ,柴达木盆地达参 1井井深 4 6m以下的沉积物内 ,水生生物化石有很高的丰度和分异度。介形类为Cyprideistorosa- Ilyocyprisinermis组合 ,伴生有轮藻类、腹足类、双壳类、植物和鱼类等化石。井深 4 6～ 10m ,为全球末次冰期盛冰阶 (2 5～ 10kaB P )沉积 ,当时气候极端干冷 ,出现干盐湖地质事件 ,沉积物由湖相泥岩迅速演变为石盐层 ,生物化石罕见 ,几近绝迹。平均 4 0m厚的石盐沉积遍及三湖 (台吉乃尔湖、达布逊湖和霍布逊湖 )地区 ,形成了该区天然气赖以保存的最后一道屏障———天然气藏的盖层。井深约10m以上 ,为全新世暖期或称现代间冰期沉积物 ,渐变为浅湖相泥岩和粉砂岩夹膏盐沉积。当时处于氧同位素阶段 1,湖水盐度逐渐降低 ,水生生物丰度和分异度再度增高 ,介形类更替为半咸水—淡水Candonaneglecta- Candoniellalactea组合 ,伴生有丰富的轮藻、腹足类、双壳类等。直到现代 ,台吉乃尔湖、达布逊湖和霍布逊湖以南由于受昆仑山充足的淡水补给影响 ,水生生物丰富。三湖以北 ,远离主要淡水补给区 ,水体较咸 ,介形类则为典型的盐湖介形类Eucyprisinflata所替代 ,膏盐沉积比三湖以南明显增多。
In the late Late Pleistocene, the fossils of aquatic fossils in the sediments below the depth of 46m in the Dashen 1 well of the Qaidam Basin have high abundance and differentiation. The orthopedic class is a combination of Cyprideistorosa-Ilyocyprisinermis associated with fossils of the order of the round algae, gastropods, bivalves, plants and fish. Well depth 4 6 ~ 10m, for the last ice age Shengping (2 5 ~ 10kaB P) deposition, when the climate was extremely dry and cold, dry salt lake geological events, the rapid evolution of sediments from lake mudstone to rock salt, rare biological fossils, near Extinct. An average of 40m of rock salt is deposited throughout the three lakes (Tajine Lake, Dabson Lake and Hobson Lake), forming the last barrier of natural gas in the area - the cap of natural gas reservoirs. Well depth of about 10m or more, for the Holocene warm or modern interglacial sediments, gradually changed into shallow lacustrine mudstone and siltstone sandwiches. At that time, in the stage of oxygen isotope 1, the salinity of the lake gradually decreased and the abundance and differentiation of aquatic organisms increased again. The replacement of the ostracods with the combination of brackish water and freshwater Candonaneglecta-Candoniellalactea was accompanied by abundance of Chaetoceros, Gastropods, Bivalve and so on. Until modern times, the south of Tajine Lake, Dabson Lake and Hobson Lake were rich in aquatic organisms due to the abundant supply of freshwater from the Kunlun Mountains. North of the Three Lakes, away from the main freshwater recharge area, the water body is salty, and the Ostracoda is replaced by the typical salt lake Eucyprisinflata. The deposition of gypsum salt is obviously more than the south of the Three Lakes.