摘要
通过对西藏面积最大(1940km2)和海拔最高(4718m)的大湖—纳木错的调查,发现纳木错周缘有大面积分布的湖相沉积。U系法和14C法测年结果表明,纳木错沿岸湖相沉积的时代为晚更新世和全新世。根据纳木错周缘不同时代湖相沉积物的范围分布的变化,探讨了湖泊演化,计算出纳木错流域古降水量。研究结果,本区自晚更新世以来气候环境由湿润转向干旱,自全新世以来降雨量呈下降趋势。
Field surveys of the Nam Co—a large lake with the biggest area (1940 km^2) and highest elevation above sea level (4718 m) in Tibet show that there are extensive lacustrine sediment around the Nam Co.Uranium-series and ()^(14)C dating indicate that the lacustrine sediments along the shores of the Nam Co are late Pleistocene and Holocene in age.The lake evolution was studied according to the change in distribution of lacustrine sediments of different ages around the Nam Co and the paleo-precipitation in the Nam Co drainage area was calculated.The study indicates that the climate in the study area turned from wet to dry since the late Pleistocene and that the precipitation has had a tendency of decrease since the Holocene.
出处
《地质力学学报》
CSCD
2004年第4期337-343,共7页
Journal of Geomechanics
基金
国土资源大调查项目 "西藏纳木错地区第四纪环境演变调查研究"(编号DKD2001006)
"西藏当雄幅1:25万区域地质调查"(编号DKD9901001)的阶段性研究成果。
关键词
晚更新世
湖相沉积物
西藏纳木错
全新世
降水量
测年
演化
量变
面积
变化
Nam Co,Tibet
lacustrine sediments
isotopic age determination
late Pleistocene-Holocene
paleo-precipitation
