| 湖泊沉积中的10Be含量变化--有助于识别第四纪古冰川的有无 |
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| 引用本文： | 张信宝.湖泊沉积中的10Be含量变化--有助于识别第四纪古冰川的有无[J].冰川冻土,2005,27(3):438-443. |
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| 作者姓名： | 张信宝 |
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| 作者单位： | 中国科学院、水利部,成都山地灾害与环境研究所,四川,成都,610041;中国科学院,地球环境研究所黄土与第四纪地质国家重点实验室,陕西,西安,710075 |
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| 基金项目： | 国家自然科学基金
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国家重点基础研究发展计划(973计划) |
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| 摘 要： | 20世纪50 -70年代核试验产生的137Cs 尘埃, 在现代冰川和非冰川湖泊沉积剖面中的深度分布存在明显差异. 同理, 大气宇宙射线成因的长半衰期 10Be尘埃, 在第四纪冰川和非冰川湖泊沉积剖面中的深度分布也应存在差异. 第四纪冰川湖泊, 冰期时流域内冰雪和10Be的累积量大于消融量, 间冰期时冰雪和10Be的消融量大于累积量. 因此, 冰川湖泊冰期的10Be入湖通量小于间冰期. 湖泊沉积剖面10Be浓度的波动, 很可能表征流域内冰雪消融与累积的变化. 非冰川湖泊, 不存在冰川的累积与消融对10Be入湖通量的影响. 开展第四纪冰川与非冰川湖泊沉积10Be含量变化的对比研究, 有可能为破译中国东部中低山区古冰川和青藏高原大冰盖的世纪之争提供新的证据.
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| 关 键 词： | 湖泊沉积 137Cs 现代冰川 10Be 古冰川 |
| 文章编号： | 1000-0240(2005)03-0438-06 |
| 修稿时间： | 2004年11月7日 |
Analyses of the 10Be Concentration Fluctuations in Lake Deposits for Identification of the Paleo-glaciers in Quaternary Period |
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| ZHANG Xin-bao.Analyses of the 10Be Concentration Fluctuations in Lake Deposits for Identification of the Paleo-glaciers in Quaternary Period[J].Journal of Glaciology and Geocryology,2005,27(3):438-443. |
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| Authors: | ZHANG Xin-bao |
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| Abstract: | The shapes of depth distribution profiles of fallout { { } 137 Cs }, which were produced by nuclear weapon testing during the period of 1950-1970, are different in the deposits between non-glacial and glacial lakes. As fallout { { } 137 Cs } with a short half life of 30 ^17 a in modern lake deposits, depth distribution shapes of cosmogenic radionuclide 10 Be with a long half of 1.5 Ma should be different in the deposits between glacial and non-glacial lakes during Quaternary period. For a glacial lake, the amounts of accumulated ice layers and the containing 10 Be radionuclide are greater than the delivering values by meltwater over the catchment in glacial periods, while the amounts are less the delivering values in inter-glacial period. The fluctuations of 10 Be concentrations in deposit profiles of glacial lakes may reflect the changes of ice accumulation and melting during the quaternary period. For non-glacial lakes, there are no such effects of ice accumulation and melting on the { { } 10 Be } delivering yields from the catchment exist during the Quaternary period. A comparative study on { { } 10 Be } in deposits between glacial and non-glacial lakes may have great potential for solving the century s debate on the paleo-glaciers in the eastern low-middle mountain regions and on the ice sheet in the Tibet Plateau of China. |
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| Keywords: | lake deposit { { } 137 Cs } modern glacier 10 Be ancient glacier |
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