摘要
本文测定了柯西河流域中尼跨境河段23个河床表层沉积物样品的矿物组分及微量元素含量。结果表明,上、下游沉积物中长石/石英比分别为0.55和0.37,碳酸盐矿物分别以方解石(12%)和白云石(3%)为主,反映上游化学风化强度小于下游;上下游微量元素Zr、Hf、Cs、Li的分布差异与源岩及河流分选作用有关;与其他发源于青藏高原的河流相比,科西河沉积物中∑REE含量总体较高,主要受源区重矿物影响,其中上游∑REE低于下游,与河流分选造成的重矿物分布有关;LREE明显富集及δEu负异常(0.3~0.59)指示沉积物为长英质物源,结合微量元素图解和富集因子分析表明沉积物主要来源于花岗片麻岩,受人为影响较小。
The mineral and elemental characteristics of river sediments are helpful to explore the weathering process and material sources of the catchment. As an important tributary of the Ganges, the Koshi river is a typical cross-border river in South Asia, but little is known on the minerals and elements in the sediments of the Koshi river basin. In this study, 23 sediment samples from the Koshi river were analyzed to determine the mineral components and trace element concentrations. Results show that the ratio of feldspar/quartz of sediments from the upstream and downstream was 0.55 and 0.37, respectively, carbonate minerals were mainly as the form of calcite(12%) in upstream while dolomite(3%) in downstream, indicating a relatively lower chemical weathering intensity in the upper reaches. The distributions of Zr, Hf, Cs and Li are related to the source rock and river sediment sorting. ∑REE in the sediments of the Koshi river are higher than those of other rivers originating from the Tibetan Plateau, which is mainly affected by heavy minerals in the source area. ∑REE in the upstream are lower than those in the downstream, reflecting the uneven distribution of heavy minerals during transportation. The feature of LREE enrichment and negative Eu anomaly(0.3~0.59) indicated the felsic source. Combined with the trace element diagrams and the EF calculation, we suggested that the materials are mainly from the granitic gneiss in the source region with negligible contribution from human activities.
作者
李明月
孙学军
Kabita Karki
曾辰
张永利
张凡
李明慧
张强弓
LI Ming-yue;SUN Xue-jun;Kabita Karki;ZENG Chen;ZHANG Yong-li;ZHANG Fan;LI Ming-hui;ZHANG Qiang-gong(Key hiboralory of Tibetan Environment Changes and Land Surface Processes,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;Department of Geology,Northeastern University,Shenyang 110819,China;Center for Excellence in Tibetan Plateau Earth Sciences,Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2019年第5期989-997,共9页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金国际合作与交流项目(41761144078)
国家自然科学基金项目(41671074)
关键词
柯西河
沉积物
矿物
元素
风化作用
物源
Koshi River
sediments
minerals
elements
chemical weathering
provenance
