末次盛冰期新疆的湖泊记录及其气候环境意义

以新疆地区所开展的湖泊研究工作为基础,结合黄土和冰川记录,讨论了新疆地区末次盛冰期气候环境状况。迄今为止,新疆具有LGM记录的湖泊并不多。乌伦古湖、博斯腾湖和巴里坤湖等湖泊钻孔岩心的地层显示,在末次盛冰期期间,这些湖泊岩心的岩性普遍出现砂-粉砂质沉积类型特征、粒度相对较粗;巴里坤湖的孢粉组合以黎科和代表极端环境的菊科为主,孢粉总量较低。结果表明:在末次盛冰期期间新疆地区湖面较低、湖泊萎缩、气候环境极端干旱,不存在之前研究所认为的末次盛冰期期间气候冷湿、湖面上升的状况。对新疆末次盛冰期气候环境的状况及其机制需要重新认识。

LAKE RECORDS DURING THE LAST GLACIAL MAXIMUM FROM XINJIANG,NW CHINA AND THEIR CLIMATIC IMPLICATIONS

This study deals with the climate changes during the Last Glacial Maximum(LGM)upon the latest work in Xinjiang. Possible mechanisms driving the climate change are discussed. With the study of the lacustrine cores from the Wulungu, Bosten and Balikun lakes, it is found that, during the period of LGM, the samples from these lakes are characterized by sandy and/or silty deposits with a low content of organic matters. The pollen assemblage of the Balikun lake shows that this area was dominated by Chenopodiaceae and Asteraceae during the LGM,and characterized by the lowest pollen abundance in the whole cores. It is inferred that the water level of the lakes in Xinjing area were low or close to drying up during the LGM, implying that the climate of this area were dramatically dry. This result does not support the interpretation of an extremely humid LGM in Central Asia.