Climatic changes documented by stable isotopes of sedimentary carbonate in Lake Sugan,northeastern Tibetan Plateau of China,since 2 kaBP

查看全文 作　　者：QIANG [1,2]Mingrui;CHEN [2]Fahu;ZHANG [2]Jiawu;GAO Shang-[1]yu;ZHOU [2]Aifeng 机构地区：[1]China Center of Desert Research at Beijing Normal University and Key Laboratory of Environmental Changes and Natural Disaster, Ministry of Education of China, Beijing Normal University, Beijing 100875, China;[2]Center for Arid Environment and Paleoclimate Research (CAEP), Natiunal Laboratory of Western China's Environmental System, Ministry of Education of China, Lanzhou University, Lanzhou 730000, China 出　　处：《Chinese Science Bulletin》索引2005年第50卷第17期,共10页 基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.401 25001,40301051,40301050 and 40421101). 摘　　要：Lake Sugan at the northern edge of the Qaidam Basin was selected as the research object. The temporal se-quence of sedimentary cores retrieved from Lake Sugan since 2 kaBP was reconstructed using the 210Pb, AMS 14C and conventional 14C dating methods. Carbon and oxygen iso-topes of carbonate in the fine-grained lake sediments were analysed. Combined with the changes of δ 18O values of sur-face water and air temperature observation data in the study area, it might be thought that the δ 18O value of the carbon-ate indicates effective moisture, and the changes in δ 13C val-ues are related to annual freeze-up duration of the lake and indirectly indicate air temperature changes in winter half year. From the above, the sequence of climatic changes in the region since 2 kaBP was established. The climatic changes experienced five stages: Warm-dry climate during 0-190 AD; cold-dry climate during 190-580 AD; warm-dry cli-mate during 580-1200 AD (MWP); cold-wet climate during 1200-1880 AD (LIA); cold-dry climate during 1880-1950 AD; and climate warming since 1950s. The air temperature changes in winter half year reflected by carbon isotope since 2 kaBP are in good agreement with the historical literature records and other geologic records, which shows that the climate changes recorded by the stable isotopes from Lake Sugan since 2 kaBP are of universal significance. 关 键 词：气候变化 同位素 稳定性 碳酸盐 沉积作用 青藏高原