| 希门错2000多年来气候变化的湖泊记录 |
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| 引用本文： | 王苏民,薛滨,夏威岚.希门错2000多年来气候变化的湖泊记录[J].第四纪研究,1997,17(1):62-69. |
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| 作者姓名： | 王苏民 薛滨 夏威岚 |
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| 作者单位： | 中国科学院南京地理与湖泊研究所湖泊沉积与环境开放研究实验室!南京，210008，中国科学院南京地理与湖泊研究所湖泊沉积与环境开放研究实验室!南京，210008，中国科学院南京地理与湖泊研究所湖泊沉积与环境开放研究实验室!南京，210008 |
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| 摘 要： | 本文根据青藏高原东部希门错短柱岩芯XM9201沉积物的物理、化学和生物指标的综合分析，讨论了该区2000多年来的气候变化过程。结果表明，2000多年来希门错地区总体表现出变暖的趋势，可以区分出4个阶段，即780～430B．C，480～1460A．D．的暖期和430B．C．～480A.D，1460～1900A．D．的冷期。另外，还对比我国东西部历史气候记载及冰芯研究，探讨了不同气候事件的特点。
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| 关 键 词： | 希门错 气候变化 湖泊记录 |
| 收稿时间： | 1996-10-08 |
| 修稿时间： | 1996-10-31 |
LAKE RECORD OF CLIMATIC CHANGE IN THE PAST 2000 YEARS OF XIMEN CUO(LAKE) |
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| Wang Sumin, Xue Bin, Xia Weilan.LAKE RECORD OF CLIMATIC CHANGE IN THE PAST 2000 YEARS OF XIMEN CUO(LAKE)[J].Quaternary Sciences,1997,17(1):62-69. |
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| Authors: | Wang Sumin Xue Bin Xia Weilan |
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| Institution: | Lake Sediment and Environment Laboratory. Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 |
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| Abstract: | The climate in the last 2000 years has been highlighted in the field of global change' It is a very important time stream in PAGES to link the geological record with instrumental--gauge data' The past study in China for the climatic change of this time stream is concentrated in the historical record and ice core, because they all have very good resolution' The study on lake sediments is also a good tool for this purpose' With the support by lake drilling session of CCP project "Study on the Tibetan Plateau uplifting, environmental change and ecological system", the authors choose the Ximen Cuo, which is of little human impact, for the study of the palaeoclimate in the past 2 000 years.Ximen Cuo （33° 23' N, 101°08'E） is a modern glacial lake. It is semi-closed lake and infilled by melt water. The lake has a mean water depth of 40m, and covers an area of 3.8 km2. The catchment area is only 50 km2 and the lake has an altitude of 4020 a. s. l. The core site is at the lake bay, and the core （XM9201） has a depth of 1.47m.The AMS radiocarbon located at the organic mud of 1.4m deep is dated at 2 600±120 a B. P. Meanwhile the radionuclide measurement suggest that the sedimentary rate is about 0.68 mm /a, coinciding with the depositional rate inferred from 14C data. Therefore, the sample at the interval of 2 cm has a resolution of 30 ~40 yr.The experimental measurement are concentrated on magnetic susceptibility （x1f,.xhf, xfd）, sedimentary pigment （CD, TC, Osc, Myx） and stable carbon isotope （δ13Corg）.The high x1f value is consistent with more debris inflow, i. e. much melt water during the warm climate and vise versa. The content of pigment is depended on warm extent of the climate. The variation of the content of 13Corg is attributed to the type of sedimentary organic matter. When the input organic matter is of C3way in photosynthesis, the high value coincides with kryoclimathem.According to the synthetic analysis in physics, chemistry and biology, the proxies have suggested that the Ximen Cuo （lake）, which lies in the eastern Tibetan Plateau, has undergone a climatic change something like that of historical record in eastern China, especially the climatic events, such as "Medieval Warm Period", "little Glacial" etc', unlike the ice core record in western Tibetan Plateau' However, both lake record and ice core research suggest the same characteristics, i' e', the climate has a warm tendency in the last 2000 years' ms could be a kind of regional feature for Tibetan area.The detail core study indicates that the climate in the last 2000 years has generally undergone 4 obvious stages, i. e. the thermoclimathem of 780~430 B. C. and 480~1460A. D., and the kryoclimathem of 430 B. C.~480 A. D. and 1460~1900 A. D. The climate began to get warmer since 1930's from the record.This paper has also probed into the subordinate oscillations of the different stages. It seems that the so--called "Medieval Warm Period" in Ximen Cuo is characteristic of distinct unstability, which is obviously different from the historical record in eastern China. In addition, the two kryoclimathems are geomorphicaly consistent with the two tilts of modern Ximen glacial lake, i. e. 3 kin and 1 km distant from modern edge of glacial respectively.The study indicates that limnological study is also an effective tool for studying the historical climate, especially in the areas where there are no good materials such as historical records, tree--ring, ice--core etc. Sedimentary pigment and susceptibility proxies are very effective indicators for historical climate reconstruction, especially for this land of glacial lake. However, the great disadvantage lies in the resolution rate and dating control. Only if this is improved that more historical events and sub tie characteristics could be found. |
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| Keywords: | Ximen Cuo climatic change lake record |
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