| 西藏枪勇冰川冰下富碎屑化学沉淀特征与冰下过程 |
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| 引用本文： | 罗日升,曹峻,刘耕年,崔之久.西藏枪勇冰川冰下富碎屑化学沉淀特征与冰下过程[J].地理学报,2003,58(5):757-764. |
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| 作者姓名： | 罗日升 曹峻 刘耕年 崔之久 |
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| 作者单位： | 北京大学环境学院,北京,100871 |
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| 基金项目： | 国家自然科学基金项目(40271014，90102016)~~ |
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| 摘 要： | 西藏枪勇冰川是我国现代大陆性冰川之一，在其外缘冰床背冰面的基岩表面和节理裂隙中发现了富碎屑化学沉淀，为研究冰岩界面的物理、化学过程提供了良好载体。对该区富碎屑化学沉淀理化特征的研究表明：枪勇冰川冰下存在压力融水，冰下碎屑，特别是陆源气溶胶粉尘来源的碎屑，能与融水及其中溶解的CO2发生化学反应，释放出Ca^ ；Ca^ 随融水向下游方向迁移，在冰床背冰面，由于上覆压力减小，融水中的CO2逸出并发生复冰作用，使融水中的Ca^ 重新富集，形成CaCO3沉淀，并将融水中的粉砂粘粒碎屑胶结，形成富碎屑化学沉淀：枪勇冰川冰下融水的存在，证明其冰下存在温度接近融点的融区，有类似于温性冰川的滑动过程。
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| 关 键 词： | 冰下化学沉淀 冰下过程 大陆性冰川 西藏枪勇冰川 |
| 收稿时间： | 2003-02-25 |
| 修稿时间： | 2003年2月25日 |
Characteristics of the Subglacially-formed Debris-rich Chemical Deposits and Subglacial Processes of Qiangyong Glacier |
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| LUO Risheng,CAO Jun,LIU Gengnian,CUI Zhijiu.Characteristics of the Subglacially-formed Debris-rich Chemical Deposits and Subglacial Processes of Qiangyong Glacier[J].Acta Geographica Sinica,2003,58(5):757-764. |
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| Authors: | LUO Risheng CAO Jun LIU Gengnian CUI Zhijiu |
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| Institution: | College of Environmental Sciences, Peking University, Beijing 100871, China |
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| Abstract: | Subglacially-formed debris-rich chemical deposits were found both on bedrock surface and in bedrock crevice at the edge of Qiangyong Glacier, one of the continental glaciers in Tibet. Grain size distribution, internal structures and chemical components of the chemical deposits were analyzed. It can be inferred that the temperature of some parts of the ice-bedrock interface is close to melting point and there exists pressure melting water under Qiangyong Glacier. Debris, especially those from continental aerosols, can release Ca++ in the water. At the lee-side of obstacles on glacier bed the CO2 in the melted water might escape from the water and the melted water might refreeze due to the dramatically reduced pressure, making the enrichment and precipitation of CaCO3. The existence of subglacial melting water and the process of regelation under Qiangyong Glacier indicates that sliding could contribute some proportion to the total movement of Qiangyong glacier and it belongs to multiplex cold-temperate glaciers. |
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| Keywords: | Qiangyong Glacier subglacially-formed chemical deposit subglacial process continental glacier |
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