SOLUTE PROVENANCE, TRANSPORT AND DENUDATION IN A HIGH ARCTIC GLACIERIZED CATCHMENT

Recent understanding of chemical weathering in glacierized catchments has been focused on mid-latitude, Alpine catchments; comparable studie s from the high latitudes are currently lacking. This paper attempts t o address this deficiency by examining solute provenance, transport an d denudation in a glacierized catchment at 78 degrees N in the Svalbar d High Arctic archipelago. Representative samples of snow, glacier ice , winter proglacial icing and glacier meltwater were obtained from the catchment during spring and summer 1993 and analysed for major ion ch emistry. Seasonal variations in the composition of glacier meltwater o ccur and are influenced by proglacial solute acquisition from the icin g at the very start of the melt season, and subsequently by a period o f discharge of concentrated snowmelt caused by snowpack elution; weath ering within the ice-marginal channels that drain the glacier, particu larly carbonation reactions, continues to furnish solute to meltwater when suspended sediment concentrations increase later in the melt seas on. Partitioning the solute flux into its various components (sea-salt , crustal, aerosol and atmospheric sources) shows that c. 25% of the t otal flux is sea salt derived, consistent with the maritime location o f the glacier, and c. 71% is crustally derived. Estimated chemical den udation, 160 meg m(-2) a(-1) sea salt-corrected cation equivalent weat hering rate, is somewhat low compared with other studied glacierized c atchments (estimates in the range 450-1000 meg m(-2) a(-1)), which is probably attributable to the relatively short melt season and low spec ific runoff in the High Arctic. A positive relationship was identified between discharge and CO2 drawdown owing to carbonation reactions in turbid meltwater. (C) 1997 John Wiley & Sons, Ltd.