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Geochemical investigation of weathering processes in a forested headwater catchment: mass-balance weathering fluxes

Published online by Cambridge University Press:  05 July 2018

B. F. Jones  and
J. S. Herman
B. F. Jones*
Affiliation:
432 National Center, US Geological Survey, 12201 Sunrise Valley Dr., Reston, VA 20192, USA
J. S. Herman
Affiliation:
Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904-4123, USA
*
*E-mail: bfjones@usgs.gov
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Abstract

Geochemical research on natural weathering has often been directed towards explanations of the chemical composition of surface water and ground water resulting from subsurface water-rock interactions. These interactions are often defined as the incongruent dissolution of primary silicates, such as feldspar, producing secondary weathering products, such as clay minerals and oxyhydroxides, and solute fluxes (Meunier and Velde, 1979). The chemical composition of the clay-mineral product is often ignored. However, in earlier investigations, the saprolitic weathering profile at the South Fork Brokenback Run (SFBR) watershed, Shenandoah National Park, Virginia, was characterized extensively in terms of its mineralogical and chemical composition (Piccoli, 1987; Pochatila et al., 2006; Jones et al., 2007) and its basichydrology. O’Brien et al. (1997) attempted to determine the contribution of primary mineral weathering to observed stream chemistry at SFBR. Mass-balance model results, however, could provide only a rough estimate of the weathering reactions because idealized mineral compositions were utilized in the calculations. Making use of detailed information on the mineral occurrence in the regolith, the objective of the present study was to evaluate the effects of compositional variation on mineral-solute mass-balance modelling and to generate plausible quantitative weathering reactions that support both the chemical evolution of the surface water and ground water in the catchment, as well as the mineralogical evolution of the weathering profile.

Type
Research Article
Information
Mineralogical Magazine , Volume 72 , Issue 1 , February 2008 , pp. 65 - 69
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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References

Bowser, CJ. and Jones, B.F. (2002) Mineralogic controls on the composition of natural waters dominated by silicate hydrolysis. American Journal of Science, 302, 582–662.CrossRefGoogle Scholar
Bricker, O.P., Jones, B.F. and Bowser, CJ. (2003) Mass-balance approach to interpreting weathering reactions in watershed systems. Pp. 119–132 in: Treatise on Geochemistr. (Drever, J.I., editor). Vol. 5, Elsevier, New York.Google Scholar
Jones, B.F., Pochatila, J., Conko, K.M. and Webster, D.M. (2007) Chemical and mineralogical composition of saprolite from South Fork Brokenbaek Run Watershed, Shenandoah National Park, Virginia. 12th International Symposium on Water-Rock Interactions, Guilin, China.Google Scholar
Meunier, A. and Velde, B. (1979) Weathering mineral facies in altered granites: the importance of local small-scale equilibria. Mineralogical Magazin. 43, 261–268.CrossRefGoogle Scholar
Meunier, A., Sardini, P., Robinet, J. C. and Pret, D. (2007) The petrography of weathering processes: facts and outlooks. Clay Minerals, 42, 415–435.CrossRefGoogle Scholar
O'Brien, A.K., Rice, K.C., Bricker, O.P., Kennedy, M.M. and Anderson, R.T. (1997) Use of geochem-ical mass balance modelling to evaluate the role of weathering in determining stream chemistry in five mid-Atlantic watersheds on different lithologies. Hydrological Processes, 11, 719–744.3.0.CO;2-2>CrossRefGoogle Scholar
Piccoli, P.M. (1987) Petrology and geochemistry of the Old Rag Granite on Old Rag Mountain, Central Virginia. Masters thesis, University of Pittsburgh, USA.Google Scholar
Plummer, L.N. and Back, W. (1980) The mass balance approach: Applications to interpreting the chemical evolution of hydrologic systems. American Journal of Science, 280, 130–142.CrossRefGoogle Scholar
Pochatila, J. (2000) Geochemical Investigation of Weathering Processes in a Forested-Headwater Catchment: A Mass-Balance Approach. Masters thesis, University of Virginia, USA.Google Scholar
Pochatila, J., Jones, B.F., Conko, K.M. and Webster, D.M. (2006) Chemical and Mineralogical Composition of Saprolite from South Fork Brokenbaek Run Watershed, Shenandoah National Park, Virginia. US Geological Survey, Open-File Report 2006–1366, 20 pp.Google Scholar
Scanlon, T.M. (1999) Modeling Stream Discharge and Dissolved Silica Variations in a Forested Headwater Catchment: A Hydrological Pathway Approach. Masters thesis, University of Virginia, USA.Google Scholar
Velbel, MA. and Price, J.R. (2007) Solute geochemical mass-balances and mineral weathering rates in small watersheds: Methodology, recent advances, and future directions. Applied Geochemistry, 22, 1682–1700.CrossRefGoogle Scholar