Meltwater routing in a high arctic glacier, Hannabreen, northern Spitsbergen

Abstract

Electrical conductivity and chemistry of meltwaters draining glaciers have been used to study spatial differences and seasonal variations in melwater routing (e.g. Collins 1977, 1979 Tranter et al. 1993, Hodgkins et al. 1995). Collins (1977,1979) suggested a model to separate bulk runoff into a rapid englacial flow component and a delayd subglacial flow component. The model is based on the higher electrical conductivity of the subglacial component than the englacial component, assuming the conductivity of each component to be relatively constant throughout the ablation season. Tranter et al. (1993) argues that althrough such a model describes many features of the subglacial drainage system, it is unlikely that the chemical composition of each component is constant over the ablation season. The anionic composition of meltwater seems to provide a diagnostic basis for determining the flow routing of meltwater. SO₄ ^2- is particularly useful, because sulphide oxidation is a rapid reaction which commonly goes to completion in a distributed drainage system, exhausting sources of reactive sulphates before meltwater enters the channelized system (Tranter et al. 1993). SO₄ ^2- is therefore regarded as a trace element for the delayed subglacial flow component.