| 青海湖全新世以来古环境参数的研究 |
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| 引用本文： | 张彭熹,张保珍,钱桂敏,李海军,徐黎明.青海湖全新世以来古环境参数的研究[J].第四纪研究,1994,14(3):225-238. |
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| 作者姓名： | 张彭熹 张保珍 钱桂敏 李海军 徐黎明 |
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| 作者单位： | 中国科学院盐湖研究所 |
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| 摘 要： | 作者根据青海湖水下近代沉积物岩芯中胖真星介(Ｅｕｃｙｐｒｉｓｉｎｆｌａｔａ)壳微量碳酸盐占δ１８Ｏ、δ１３Ｃ以及单体介壳的微量元素分析，重建了青海湖区冰后期以来的古气候环境演化序列，并在此基础上通过对全湖湖水水温、盐度、同位素以及现生胖真星介的δ１８Ｏ和微量元素分析，定量地求取了１２０００ａＢ．Ｐ．以来各时段的古湖盐度、水位和水温变化数据。研究结果表明：古青海湖在全新世早期湖水含盐量在２０ｇ／Ｌ上下波动，进入大西洋期湖水盐度才波动下降，５Ｏ００—２５００ａＢ．Ｐ．年间湖水含盐量在５ｇ／Ｌ以下，此后湖水盐度才缓慢上升，达到今日的１４．１３４ｇ／Ｌ；全新世早期古青海湖处于浅湖环境其平均水位比现代低约８ｍ，全新世高湖面出现在６５００、５１００和３９００—３１００ａＢ．Ｐ．年间，水位比现今仅高１７—１８ｍ；全新世大暖期的时限为９３００—５３００ａＢ．Ｐ．，该时段古湖平均水温比现代高１．８℃。
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| 关 键 词： | 环境参数 全新世 青海湖 |
THE STUDY OF PALEOCLIMATIC PARAMETER OF QINGHAI LAKE SINCE HOLOCENE |
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| Institution: | Institute of Salt Lakes, Chinese Academy of Sciences |
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| Abstract: | Abstract:Qinghai Lake is the largest inland saline lake in China. Its sediments containlarge amount of information on paleoclimate environment cLanges. fossils of ostracodal in the sediments have been taken as the ideal samples for getting such information, because of its enrichment in the sediments, sample type, the compositionof CaCO3 in its shell is only aragonite and no recrystallization was found.The analyse of δ(18)O, δ(13)C of trace carbonates and the analyse of trace elementsin single shell of Eucypris inflata in Core QH-16-A (deep: 5.22m) of Qinghai Lakehave provided useful information in recovering the evolution sequence of paleoclimate since 12 000a B.P. The study of δ(18)O, Sr/Ca, δ(13)C value at different salinityand trace elements analyse made it possible to calculate the ancient water temperature, ancient salinity, with the following results obtained:1. In early Holocene, the salinity of Qinghai Lake water was relatively high,although it varied greatly but the salt content in the water was still higher than inthe present. The highest value reached up to 29g/L at about 8 400aB.P. From 7 700-5 100a B.P. the salt content decreased greatly and began to increase from 3 200aB.P. to present.2. Qinghai Lake in Holocene was a shallow lake, the water depth varied around10m. It became deeper in Atlantic Period. The high lake level occurred in6 400, 5 000, 3 500a B.P. and was 17.5m higher than the present lake level. Thedrop of the water level occurred only in the past 2 500 years.3. The variation of ancient water temperature (in July) of Qinghai Lake inHolocene was within 3to. The average lake water temperature in the Most WarmPeriod is 1.8℃ higher than the present lake water temperature. The highest watertemperature is only 2.2℃ higher than that of present. The water temperature inYounger Dryas Period in 10 000 years is still 0.2-0.5℃ higher than that of present,and is 1℃ lower compared with lake water temperature in 10 000a B.P. The frequent variations of temperature occuved in the past 2 500 years. It still needs to bestudied whether it suggests that the climate will become warmer.4. The frequent changes of water level, occurred in temperature increasingperiod, suggest that the unstability of climate environment parameters. If the climatewill become warmer in the future, with the coming of our expected optimum climate period, we must take a sharp eye on the frequent variations of climate parameter during that time, for it will bring more disasters to human beings. Thus theprediction and the prevention of natural disaster has become the focus of environment science research |
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