青藏高原东南部18ka以来气候与水文变化

青藏高原东南部众多封闭小湖的湖相沉积记录着重要的地理信息，是恢复当地晚更民以来古环境演变的理想材料。西藏海登湖和仁同分辨率的花粉组合，ＡＭＳ＾１４Ｃ测年及磁化率和有机质含量测定，揭示了研究区与鳊季风密切相关的古植被，古气候和古水文变化历史。高分辨率的花粉记录反映，在１６ｋａＢｍ，Ｐ，以前花粉组合以黎科（Ｃｈｅｎｏｐｏｄｉａｃｅａｅ）和蒿属（Ａｒｔｅｍｉｓｉａ）为主，花粉浓度很低，应为荒漠草原植被。

CLIMATIC AND HYDROLOGICAL CHANGES IN THE SOUTHEASTERN QINGHAI-TIBETAN PLATEAU DURING THE PAST 18 000 YEARS

The lakes in the southeastern Qinghai Tibetan Plateau contain exceptional information about the detailed history of Late Pleistocene climatic and hydrological evolutions. The high resolution and well dated records of pollen, magnetic susceptibility and organic content from Hidden Lake and Ren Co revealed the changes in regional flora, climate and hydrology linked by the Indian monsoon, contrasting with the records from the adjacent area. The climate during the Last Glacial Maximum was cold and dry. The flora was dominated by xerophitic plants, both the January temperature and July temperature were lower than today, and shrinked monsoon that maintained a low lake level. During the early Holocene (12 500- 9 200 yr B.P.), both the temperature and precipitation increased gradually. Some deciduous broad leaved trees and conifers such as Betula, Pinus and Abies began to grow in the region. The Hypsithermal Interval (9 200 -3 000 yr B.P.) was characterized by warm and humid climate. The enhanced monsoon leads to increase in the lake level and the region was preoccupied by the evergreen and deciduous forest consisting with the broad leaved trees and conifers such as Betula, Quercus, Pinus, Abies and Picea. After 3 000 yr B.P., the climate was cooling and drying. The proportion of deciduous trees in pollen taxa decreased and the herb pollen increased.