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芒硝和砂楔是冷干气候环境的典型标志。河西走廊砂楔主要形成在晚更新世冲洪积砾石层中 ,楔体内充填的风成砂14 C年龄证明其是末次冰期的产物 ,古砂楔所对应的年均气温为- 5 6℃左右。芒硝主要分布在内陆河终端的盐湖中 ,花海芒硝矿粘土夹层中的陆生树枝残条普通14 C和AMS14 C年龄分别为 (116 0 0± 2 80 )aB .P .和 (11181± 54)aB .P .,证明芒硝层为末次盛冰期 (LGM )和新仙女木期 (YD)异常冷干气候的产物。计算表明 ,该区LGM年均气温较现在低 11～ 15℃ ,YD年均气温比现代低约 6～ 8℃。这一降温幅度与中国北方根据孢粉、砂楔、冰芯等所推测的气温下降值大体一致 ,亦与最近有关北半球高、中纬度冰期降温幅度的研究相符合
Glauber salt and sand wedge are typical signs of cold and dry climate. The sand wedge of the Hexi Corridor was mainly formed in the late Pleistocene alluvial gravel layer. The 14 C age of the aeolian sand filled in the wedge proves to be the product of the last glacial period. The annual average temperature corresponding to the ancient sand wedge is about -56 ℃ . Glauber’s salt is mainly distributed in the salt lake at the end of inland river, and the average 14 C and AMS14 C terrestrial tree branches of the flower of sea mirabilite clay are (116 0 0 ± 2 80) aB .P. And (11181 ± 54) aB .P., Demonstrating that Glauber salt is the product of an unusually cold and dry climate in the LGM and YD. The calculation shows that the average annual temperature of LGM in this area is 11 ~ 15 ℃ lower than that of nowadays, and the YD average annual temperature is about 6 ~ 8 ℃ lower than the modern one. This rate of decrease is broadly in line with the estimated temperature drop in northern China based on sporopollen, sand wedge, ice core and so on, and is in line with the recent study on the temperature drop in high and mid-latitude glacials in the Northern Hemisphere