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87Sr/86Sr as an indicator of flowpaths and weathering rates in the Plynlimon experimental catchments, Wales, U.K

Shand, P.; Darbyshire, Fiona; Gooddy, Daren; Haria, A. H.. 2007 87Sr/86Sr as an indicator of flowpaths and weathering rates in the Plynlimon experimental catchments, Wales, U.K. Chemical Geology, 236 (3-4). 247-265. 10.1016/j.chemgeo.2006.09.012

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Abstract/Summary

A knowledge of the processes involved in streamflow generation are critical to an understanding of solute transport and weathering rates in upland catchments. The determination of specific flow pathways and the formulation of process-based models have proved difficult in such terrains, largely due to the heterogeneous nature of catchments and the necessary limitations of bulked parameter models. Natural geochemical tracers have proved invaluable in developing conceptual models of catchment functioning and for constraining weathering processes and geochemical cycling. Strontium isotopes have been used as a natural tracer to calculate weathering rates for Sr and Ca, and to constrain the dominant flow pathways in two upland forested sub-catchments (Afon Hafren and Afon Hore) of the River Severn at Plynlimon in Central Wales. The dominant source of Sr in the catchments is considered to be from the weathering of silicate minerals. Weathering rates for Sr and Ca in the Afon Hafren, calculated using Sr isotopes, were similar to those derived from mass balance studies. The rates for the Afon Hore were similar for Ca, but significantly different for Sr. The reason for the difference is unclear, but may be due to additional sources (calcite) in the catchment. Strontium isotope ratios for different input sources and compartments within the catchment were characterised and helped to identify potential flow pathways. The data suggest an important role for groundwater inputs in contrast to previous models which indicated a dominant role for soil waters.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1016/j.chemgeo.2006.09.012
Programmes: BGS Programmes > Groundwater Management
CEH Programmes pre-2009 publications > Water > WA03 Developing strategic data and knowledge at a catchment scale to enable the wiser management of the water environment
CEH Sections: _ Water Quality
ISSN: 0009-3541
Additional Keywords: Weathering, Wales, River basins, GroundwaterBGS, Groundwater, Environmental tracers
NORA Subject Terms: Earth Sciences
Related URLs:
Date made live: 17 Nov 2008 15:35
URI: http://nora.nerc.ac.uk/id/eprint/3475

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