Geochemistry and provenance of bed sediments of the large rivers in the Tibetan Plateau and Himalayan region
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- 作者：Weihua Wu (12) wuwh@nju.edu.cn
Hongbo Zheng (1)
Shijun Xu (3)
Jiedong Yang (4)
Hongwei Yin (3) - 关键词：The Tibetan Plateau – ; Riverbed sediments – ; Major and trace elements – ; Sr– ; Nd isotopes – ; Chemical weathering
- 刊名：International Journal of Earth Sciences
- 出版年：2012
- 出版时间：July 2012
- 年：2012
- 卷：101
- 期：5
- 页码：1357-1370
- 全文大小：649.8 KB
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- 刊物类别：Earth and Environmental Science
- 刊物主题：Earth sciences
Geology
Geophysics and Geodesy - 出版者：Springer Berlin / Heidelberg
- ISSN：1437-3262
文摘
We investigated the geochemical characteristics of major, trace and rare earth elements and Sr–Nd isotope patterns of bed sediments from the headwaters and upper reaches of the six large rivers draining the Tibetan Plateau (the Jinsha River—Yangtze, Lancang River—Mekong, Nujiang River—Salween, Huang He—Yellow, Indus, and Yarlung Tsangpo—Brahmaputra). By using Ca/Al versus Mg/Al, La/Sc versus Co/Th, and 87Sr/86Sr versus εNd (0) binary differentiation diagrams of provenance, some typical contributors to the different catchment sediments can be identified. In the Three-River (the Jinsha, Lancang, and Nujiang Rivers) tectonomagmatic belt, acidic–intermediate-acidic volcanic rocks are very important provenance of sediments. Carbonate rocks and Permian Emeishan basalts are dominant in the Jinsha River. The Yellow River sediments have similar geochemical characteristics with loess in catchments. The Indus and Yarlung Tsangpo Rivers sediments are mainly from ultra-K volcanic rocks and Cenozoic granitoids widely distributed in the Indus–Yarlung suture. The intensity of chemical weathering in these river catchments is evaluated by calculating the chemical indices of alteration (CIA) of sediments and comparing them with bedrocks. The CIA values of the six river sediments are from 46.5 to 69.6, closing to those of bedrocks in the corresponding catchment, which indicates relatively weak chemical weathering intensity. Lithology, climate, and topography affect the chemical weathering intensity in these river catchments.