Proglacial solute fluxes and chemical weathering rates

Solute fluxes from the proglacial zone at Finsterwalderbreen are dominated by HCO3-, SO42-, Ca2+ and Mg2+, of which the snow-pack contributes by ca. 7% in total (Table 15.1). The negative silica flux is within the error margin of calculations, and indicates that there is very little Si discharged from the proglacial zone. This proglacial solute flux represents an enhancement of ca. 30% over glacial solute fluxes. A chemical weathering rate three times that for the glacial part of the catchment also signifies the proglacial zone as highly geochemically reactive. The elevated rates of chemical weathering can be attributed to the relatively young age of proglacial material (<100 yr) and the close coupling between glacial bulk meltwaters and proglacial sediments, achieved by an extensive active layer groundwater system and associated ephemeral streams.

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