Труды сотрудников ИЛ им. В.Н. Сукачева СО РАН

[Text] / M. L. Bagard [et al.] // Geochim. Cosmochim. Acta. - 2011. - Vol. 75, Is. 12. - P3335-3357, DOI 10.1016/j.gca.2011.03.024. - Cited References: 80. - This work benefited from fruitful discussions with S. Derenne, J. Templier, and T. Weber and from thorough reviews by S. Gislason, Ed Tipper and an anonymous reviewer. We also thank the associate Editor S. Hemming. B. Kieffel, Th. Perronne and E. Pelt are acknowledged for their help in measuring U and Sr isotope ratios. This work was financially supported by the French INSU-CNRS program "EC2CO-Cytrix", and CNRS program "GDRI Car-Wet-Sib". It was also supported by the funding from the Region Alsace, France, and the CPER 2003-2013 "REALISE". MLB benefited the funding of a Ph.D. scholarship from the French Ministry of National Education and Research. This is an EOST-LHyGeS contribution. . - 23. - ISSN 0016-7037РУБ Geochemistry & Geophysics

Аннотация: In order to constrain the origin and fluxes of elements carried by rivers of high latitude permafrost-dominated areas, major and trace element concentrations as well as Sr and U isotopic ratios were analyzed in the dissolved load of two Siberian rivers (Kochechum and Nizhnyaya Tunguska) regularly sampled over two hydrological cycles (2005-2007). Large water volumes of both rivers were also collected in spring 2008 in order to perform size separation through dialysis experiments. This study was completed by spatial sampling of the Kochechum watershed carried out during summer and by a detailed analysis of the main hydrological compartments of a small watershed. From element concentration variations along the hydrological cycle, different periods can be marked out, matching hydrological periods. During winter baseflow period (October to May) there is a concentration increase for major soluble cations and anions by an order of magnitude. The spring flood period (end of May-beginning of June) is marked by a sharp concentration decrease for soluble elements whereas dissolved organic carbon and insoluble element concentrations strongly increase. When the spring flood discharge occurs, the significant increase of aluminum and iron concentrations is related to the presence of organo-mineral colloids that mobilize insoluble elements. The study of colloidal REE reveals the occurrence of two colloid sources successively involved over time: spring colloids mainly originate from the uppermost organic-rich part of soils whereas summer colloids rather come from the deep mineral horizons. Furthermore, U and Sr isotopic ratios together with soluble cation budgets in the Kochechum river impose for soluble elements the existence of three distinct fluxes over the year: (a) at the spring flood a surface flux coming from the leaching of shallow organic soil levels and containing a significant colloidal component (b) a subsurface flux predominant during summer and fall mainly controlled by water-rock interactions within mineral soils and (c) a deep groundwater flux predominant during winter which enters large rivers through unfrozen permafrost-paths. Detailed study of the Kochechum watershed suggests that the contribution of this deep flux strongly depends on the depth and continuous nature of the permafrost. (C) 2011 Elsevier Ltd. All rights reserved.

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Держатели документа:
[Bagard, Marie-Laure
Chabaux, Francois
Stille, Peter
Rihs, Sophie] Univ Strasbourg, F-67084 Strasbourg, France
[Bagard, Marie-Laure
Chabaux, Francois
Stille, Peter
Rihs, Sophie] CNRS, EOST, LHyGeS, F-67084 Strasbourg, France
[Pokrovsky, Oleg S.
Viers, Jerome
Dupre, Bernard] Observ Midi Pyrenees, UMR 5563, CNRS, LMTG, Paris, France
[Prokushkin, Anatoly S.] SB RAS, VN Sukachev Inst Forest, Krasnoyarsk, Russia
[Schmitt, Anne-Desiree] Univ Franche Comte, CNRS, UMR 6249, F-25030 Besancon, France

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Bagard, M.L.; Chabaux, F...; Pokrovsky, O.S.; Viers, J...; Prokushkin, A.S.; Stille, P...; Rihs, S...; Schmitt, A.D.; Dupre, B...