Abstract
A small watershed (160 km2) located in the Massif Central (France) has been chemically, isotopically and hydrologically studied through its dissolved load, bed sediments and soils. This watershed is underlain by basaltic bedrock and associated soils in which the vegetation is dominated mainly by meadows.
Dissolved concentrations of major ions (Cl, SO4, NO3, HCO3, Ca, Na, Mg, K, Al and Si), trace elements (Rb and Sr) and strontium isotopes have been determined for two different hydrologic periods on the main stream of the Allanche river and its tributaries.
The major objectives of this study were to characterize the chemical and isotopic signatures of each reservoir occurring in the watershed. Changes in chemical and isotopic signatures are interpreted in terms of fluctuations of the different components inputs: rainwater, weathering products, anthropogenic addition.
Water quality may be influenced by natural inputs (rainwater, weathering processes) and anthropogenic additions (fertilizers, road salts, etc.). Precipitation serves as a major vehicle for dissolved chemical species in addition to the hydrosystem and, in order to constrain rain inputs, a systematic study of rainwaters is carried out over a one year period using an automatic collector. Corrections of rainwater addition using chloride as an atmospheric input reference were computed for selected elements and the “Sr/”Sr ratio. After such corrections, the geochemical budget of the watershed was determined and the role of anthropogenic additions evaluated through the relationship between strontium isotopes and major and trace element ratios. Thus, 10% of Ca and Na originate in rainwater input, 40 to 80% in fertilizer additions and 15 to 50% in rock weathering
The cationic denudation rates for this watershed are around 0.3 g s−1 km2 during low water discharge and 0.6 g s−1 km2 in high water stage. This led to a chemical denudation rate of 5.3 mm/1000 years.
For solid matter, the normalization of chemical species relative to parent rocks shows the depletion or enrichment in soils and sediments. The use of K and Ca as mobile reference illustrates the weathering state of soils and sediments relative to parent rocks. This weathering state for bed sediments range from 15 to 45% for the K normalization and from 2 to 50% for the Ca normalization. For the soils, the weathering state ranges from 15 to 57% for the K normalization and from 17 to 90% for the Ca normalization.
Article PDF
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
References
Berner-Kay, E. and Berner, R. A. (1987) The Global Water Cycle. Geochemistry and Environment, Prentice Hall, 396 pp.
Boust, D., Jouanneau, J. M. and Latouche, C. (1981) Methodologies d'interprétation des teneurs totales en métaux traces contenues dans les sediments estuariens et littoraux. Bull. Inst. Géol. Bassin d Aquitaine, Bordeaux 30, 71–86.
Brousse, R. and Lefevre, C. (1990) in Masson (ed.), Le Volcanisme en France et en Europe Limitrophe, 262 pp.
Chauvel, C. (1982) Géochimie isotopique (Nd, Sr) et géochimie des elements traces des basaltes alcalins du Massif Central français: Contraintes pétrogéné et arguments en faveur du métasomatisme mantellique, These Université de Rennes I, 180 pp.
Cullers, R. L., Basu, A. and Sutmer, L. J. (1988) Geochemical signature of provenance in sand size material in soils, stream sediments near the Tobacco Root batholith, Montana, U.S.A. Chemical Geology 70, 335–348.
Dennen, W. H. and Anderson, P. J. (1962) Chemical changes in incipient rock weathering. Geol. Soc. Amer. Bull. 73, 375–384.
De Goer de Herve, A. (1972a) La planeze de Saint-Flour, stucture et stratigraphie, Vol. I. Ann. Sci. de l'Univ de Clermont-Ferrand, Fascicule 22(47), 240.
De Goer de Herve, A. (1972b) La planeze de Saint-Flour, forme et dépôts glaciaires, Vol. II. Ann. Scien. de l'Univ de Clermont-Ferrand, Fascicule 23(48), 203.
De Goer de Herve, A. and Tempier, P. (1988) Notice explicative de la feuille Saint-Flour (1150 000). BRGM ed. 92 pp.
Drever, J. I. 1988. The Geochemistry of Natural Waters, Prentice-Hall, 2nd edition, 437 pp.
Drever, J. I. and Hurcomb, D. R. (1986) Neutralization of atmospheric acidity by chemical weathering in an alpine drainage basin in the North Cascade Mountains. Geology 14, 221–224.
Drever, J. I. and Zobrist, J.A (1992) Chemical weathering of silicate rocks as a function of elevation in the Southern Swiss Alps. Geochim. Cosmochim. Acta 56, 3209–3216.
Edwards, A. M. C. (1973a) Dissolved load and tentative solute budgets of some Norfolk catchments. J. Hydrol. 18, 201–217.
Edwards, A. M. C. (1973b) The variation of dissolved constituents with discharge in some Norfolk rivers. J. Hydrol. 18, 219–242.
Etchanchu, D. and Probst, J. L. (1988) Evolution of the chemical composition of the Garonne River water during the period 1971–1984. Hydrological Sci. 33, 3.
Faure, G. (1988). Principles of Isotope Geology, Wiley, 589 pp.
Flegal, A. R., Nriagu, J. O., Niemeyer, S. and Coale, K. H. (1989) Isotopic tracers of lead contamination in the Great Lakes. Nature 339, 455–458.
Gaillardet, J., Dupre, B. and Allegre, C. J. (1995) A global geochemical mass budget applied to the Congo Basin Rivers. Erosion rates and continental crust composition. Geochemica et Cosmochimica Acta, in press.
Garrels, R. M. and McEnzie, F. T. (1971) Evolution of Sedimentary Rocks, Norton, New York, 251 PP.
Likens, E. G., Bormann, F. H., Pierce, R. S. Eaton, J. S. and Johnson, N. M. (1977) Biogeochemistry of a Forested Ecosystem, Springer-Verlag, New York, Berlin, 147 pp.
Mast, M. A. and Drever, J. I. (1990). Chemical weathering in the Loch Vale Watershed, Rocky Mountain National Park, Colorado. Water Resour Res. 26(12), 2971–2978.
Meybeck, M. (1979) Concentrations des eaux fluviales en elements majeurs et apports en solution aux oceans. Revue de Géologie Dynamique et de Géographie Physique 21, 215–246.
Meybeck, M. (1983) Atmospheric inputs and river transport of dissolved substances. IAHSPubl. 141, 173–192.
Meybeck, M. (1987) Global chemical weathering of surficial rocks estimated from river dissolved loads. J. Sci. 287(5), 401–428.
Michell, S. J. (1970) Fluid and Particle Mechanics, Pergamon Press, 342 pp.
Middleburg, J. J., van der Weilden, C. H. and Woittiez, J. R. W. (1988) Chemical processes affecting the mobility of major, minor and trace elements during weathering of granitic rocks. Chemical Geology 68, 253–273.
Miller, W. R. and J. I. Drever (1977) Chemical weathering and related controls on surface water chemistry in the Absaroka Mountains, Wyoming. Geochim. Cosmochim. Acta. 41, 1693–1702.
Miller, E. K. and Friendland, A. J. (1994) Lead migration in forest soils: Response to changing atmospheric inputs. Environ. Sci. Technol. 28(4), 662–669.
Négrel, Ph., Allegre, C. J., Dupre, B. and Lewin, E. (1993) Erosion sources determined from inversion of major, trace element ratios and strontium isotopic ratio in riverwater: the Congo Basin case. Earth Planet. Sci. Lett. 120, 59–76.
Négrel, Ph. (1996) Multi elements chemistry of Loire estuary sediments: Anthropogenic versus natural sources. Estuarine, Coastal and Shelf Sciences, in press.
Négrel, Ph. and Roy, S. (1996) Rain chemistry in the Massif Central (France). A strontium isotopic and major elements study. Submitted to Earth Planet. Sci. Lett.
Nesbitt, H. W. (1979) Mobility and fractionation of REE during weathering of a granodiorite. Nature 279, 206–210.
Nesbitt, H. W., Markovics, G. and Price, R. C. (1980) Chemical processes affecting alkalis and alkaline earths during continental weathering. Geochim. Cosmochim. Acta. 44, 1659–1666.
Sarin, M. M., Krishnaswami, S., Dilli, K., Somayajulu, B. L. and Moore, W. S. (1989) Major ion chemistry of the Ganga-Brahmaputra river system: Weathering processes and fluxes to the Bay of Bengal. Geochim. Cosmochim. Acta. 53, 997–1009.
Sherwood, W. C. (1989) Chloride loading in the South Fork of the Shenandoah river, Virginia, U.S.A. Environ. Geol. Water Sci. 14(2), 99–106.
Stauffer, R. E. (1990) Granite weathering and the sensitivity of alpine lakes to acid deposition. Limnol. Oceanogr. 35(5), 1112–1134.
Summerfield, M. A. and Hulton, N. J. (1994) Natural controls of fluvial denudation rates in major world drainage basins. J. Geophys. Res. 99(13), 871–883.
Velbel, M. A. (1985) Geochemical mass balances and weathering rates in forested watersheds of the southern blue ridge. J. Sci. 285, 901–930.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Négrel, P., Deschamps, P. Natural and anthropogenic budgets of a small watershed in the massif central (France): Chemical and strontium isotopic characterization of water and sediments. Aquat Geochem 2, 1–27 (1996). https://doi.org/10.1007/BF00240851
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00240851