收稿日期: 2005-03-10
修回日期: 2005-09-29
网络出版日期: 2006-03-15
基金资助
国家自然科学基金项目“恒河—布拉马普特拉河Sr同位素异常源岩追踪”（编号：40273003）；中国科学院广州地球化学研究所元素和同位素地球化学实验室资助.
The Current Situation and Advance of Research on the Source Rock for the Strontium Isotope in the Himalayan Rivers
Received date: 2005-03-10
Revised date: 2005-09-29
Online published: 2006-03-15
海洋Sr同位素的变化主要是由陆地河流注入的Sr同位素的变化所引起。在全球河流中，流经喜马拉雅山地河流（恒河—布拉马普特拉河）表现出与世界上其它河流明显不同的特点，具有高 87Sr/86Sr、高[Sr]的特征。恒河—布拉马普特拉河是世界上第四大河流，是当今世界海洋Sr的重要来源。国际上，目前人们对造成喜马拉雅河流Sr异常的原因（来源）的认识，仍存较大分歧。归纳起来，主要有3种认识：一是认为来源于硅酸盐岩；二是认为来源于碳酸盐岩的风化；三是认为来源于碳酸盐岩和硅酸盐岩的风化。近年来，作者对高喜马拉雅中央结晶岩系河流Sr同位素异常及其源岩进行的研究表明，高喜马拉雅河流Sr同位素受流域地质作用的强烈影响，呈现出高 87Sr/86Sr、低[Sr]的特点。对岩石和单矿物的研究表明，中央结晶岩系变质岩（片岩、片麻岩）和花岗岩黑云母中的 87Sr/86Sr与[Rb]成正比并具有高 87Sr/86Sr、低[Sr]的特征。黑云母矿物具有的易风化性，为高喜马拉雅河流放射性87Sr提供了主要来源。恒河—布拉马普特拉河的Sr异常（高 87Sr/86SrSr和高[Sr]）则可能是反映了流经整个喜马拉雅造山带河流Sr混合平衡后的特征。
沈敢富 , 秦建华 , 冉敬 , 杜谷 . 喜马拉雅河流Sr同位素异常源岩研究现状及研究进展[J]. 地球科学进展, 2006 , 21(03) : 262 -268 . DOI: 10.11867/j.issn.1001-8166.2006.03.0262
The variation of the marine Sr isotope is largely caused with the input of the river Sr isotope. In the global rivers, the rivers draining through the Himalayan (Ganga-Brahmaputra rivers) possess the typical Sr isotope character, i.e. high 87Sr/86Sr ratio and high [Sr] concentration, which obviously differentiates from other rivers. The Ganga- Brahmaputra, the fourth largest river in the world, is important source for the marine Sr. Currently, it is still controversial for the source rock resulting in the Sr isotope anomaly in the Ganga Brahmaputra rivers. Basically, there appear three opinions for the source rock, the first opinion advocates that the source rock is the silicate rock, the second the carbonate, and the third both the silicate and carbonate. In the recent years, our research has disclosed that the Sr in the High Himalayan rivers possesses the feature of the high 87Sr/86Sr ratio and low [Sr] concentration, which is intensely affected by the specific geology in the drainage. The study on the metamorphic rocks ( schist, gneiss ) and the granites and the minerals indicates that in the biotite in the Central Crystal Series, the 87Sr/86Sr has the positive relationship with [Rb], and that the biotite also has the high 87Sr/86Sr ratio and low [Sr] concentration. The biotite is readily weathered and should be the primary source to the radioactive 87Sr of the High Himalayan rivers. The Sr anomaly (high 87Sr/86Sr ratio and high [Sr]) in the Ganga- Brahmaputra is possibly attributed to the mixing balance of the rivers draining through the whole Himalayan.
Key words： Marine Sr isotope; Himalayan; River Sr abnormally; Source rock tracing.
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