Mineralogy, major and trace element geochemistry of riverbed sediments in the headwaters of the Yangtze, Tongtian River and Jinsha River

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• 作者：Weihua Wu^a ; ^b ; ^{wuwh@nju.edu.cn} ; Shijun Xu^b ; Huayu Lu^a ; Jiedong Yang^c ; Hongwei Yin^b ; Wen Liu^d
• 关键词：The Yangtze River ; Riverbed sediments ; Mineral assemblage ; Major and trace elements ; Chemical weathering
• 刊名：Journal of Asian Earth Sciences
• 出版年：2011
• 出版时间：20 January 2011
• 年：2011
• 卷：40
• 期：2
• 页码：611-621
• 全文大小：1030 K

文摘

We collected riverbed sediments of the headwaters of the Yangtze River (Chumaer River, Tuotuo River, Gaerqu River and Buqu River), Tongtian River and Jinsha River (HTJR) flowing on the eastern Tibetan Plateau and analyzed their mineralogical features, major and trace element contents. The results show: (i) very poor correlations of Na₂O, K₂O, CaO, Ba, and Sr to SiO₂, LREE to Th, HREE to Hf, and Ta/La to Ti, and characteristics of Eu anomaly (the ratios of (Eu/Eu^*)_N range from 0.60 to 0.83 with an average value of 0.71) all indicate that the Jinsha River sediments have not undergone much mineralogical sorting; (ii) illite and chlorite are predominant clay minerals, and quartz, calcite, dolomite, albite, and K-feldspar are prevailing non-clay minerals. The characteristics of mineral assemblage indicate relatively weak chemical weathering degree in these river basins; (iii) very high contents of Fe₂O₃, MgO, TiO₂, Sc, V, Cr, Co, and Ni at Panzhihua mainly result from the huge-sized V–Ti magnetite deposits occurred in layered gabbroic intrusion; and (iv) the chemical alteration index (CIA) in the HTJR ranges from 46.5 to 69.2 and with an average value of 60.5 which indicates relatively weak weathering degree.