| 青藏高原苟鲁错湖泊沉积记录的小冰期气候变化 |
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| 引用本文： | 李世杰,王小天,夏威岚,李万春.青藏高原苟鲁错湖泊沉积记录的小冰期气候变化[J].第四纪研究,2004,24(4):578-584. |
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| 作者姓名： | 李世杰 王小天 夏威岚 李万春 |
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| 作者单位： | 中国科学院南京地理与湖泊研究所, 南京 210008 |
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| 基金项目： | 国家自然科学基金项目(批准号:40071001);中国科学院知识创新工程重要方向项目(批准号:KZCX2-SW-118)资助 |
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| 摘 要： | 文章对在青藏高原腹地可可西里地区的苟鲁错封闭湖盆中心部位获取深1m的湖底沉积岩芯进行137Cs,210Pb测年和高分辨率的碳酸盐含量、地球化学等方面的分析。结果表明:该湖泊沉积记录揭示出青藏高原腹地在近1000年时间尺度上气候变化的模式呈冷湿和温(暖)干组合为主。该岩芯覆盖了过去近1000年左右的时间尺度,其碳酸盐含量、元素地球化学的变化对中世纪暖期和小冰期的3次冷期和期间的多次暖期都有明显反映。从苟鲁错沉积记录来看,中世纪暖期的盛期处于公元1060～1140年;小冰期第1次冷期在公元1140～1340年,但在1250～1290年存在1次暖波动;第2次冷期在公元1510～1680年,但在1580～1590年和1610年左右存在暖波动;第3次冷期在公元1790～1900年;暖期主要在公元1340～1510年和1680～1790年间,但在公元1400年、1410年左右和1440～1480年间以及1710～1740年存在冷波动;20世纪暖期和全球记录相一致。该湖泊记录与古里雅冰芯记录和祁连山树轮记录以及我国东部气候历史记录都有较好的可对比性,只是在起迄年代上还存在一些差异有待深入研究。
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| 关 键 词： | 青藏高原 小冰期 湖泊沉积记录 苟鲁错 |
| 收稿时间： | 2004-01-02 |
| 修稿时间： | 2004-07-10 |
THE LITTLE ICE AGE CLIMATE FLUCTUATIONS DERIVED FROM LAKE SEDIMENTS OF GOULUCUO, QINGHAI-XIZANG PLATEAU |
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| Institution: | Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 |
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| Abstract: | The enclosed Lake Goulucuo is located in the Hoh Xil region, hinterland of Qinghai Xizang Plateau, with an drainage area of 534km 2 and an altitude of about 4 666m a.s.l., surrounded by low mountains and hills. Lake water is mainly supplied with precipitation because of no any glaciers in the lake catchment. Through the author's field research in the region in 1990 summer, the lake water surface was of 23.5km 2 in area and 1.3m in mean water depth. However, the lake was dried up and covered by a thin salt layer in 1998 summer, which is accordance with the climate record of being drier and warmer in Qinghai Xizang Plateau during this decade. The sediment core of about 1m in length was obtained at the centre of the lake, sampling with 0.5cm intervals in the upper part and 1cm in the lower part in laboratory. The top part was dated by 137 Cs and 210 Pb, which shows that lake accumulation rate is about 0.14g/cm 2·a. According to the 137 Cs peak, the depth of 6.5cm is estimated as 1963A.D. The carbonate content and geochemical elements were analysed for all samples of the core, which could be taken as an indicator of lake water concentration or desalination due to the lake water balance caused mainly by precipitation and evaporation. The result shows that this sediment core covers developed through the last 1 000 years and the change of carbonate content and geochemical elements clearly show three cold and warm stages in the Little Ice Age, which the main cold periods are 1140～1340A.D., 1510～1680A.D., 1790～1900A.D., and the main warm periods 1060～1140A.D.which may be the summit of the medieval warm stage, 1340～1510A.D., 1740～1780A.D.and the 20 century, separately. But in each main cold and warm stage, some warm events and cold events had been revealed, which means not always low or high temperature in cold or warm stage. Abrupt climate change events were happened frequently during the last 1 000 years. According to the lake record, the Little Ice Age in the central part of the Qinghai Xizang Plateau would be started from the late half of the twelve century. The results suggest that the Goulucuo Lake is a sensitive response lake to climate changes, which may provide strong evidence for the Little Ice Age climate construction on the Qinghai Xizang Plateau. |
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| Keywords: | Qinghai Xizang Plateau the Little Ice Age lake sediment record Goulucuo Lake |
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