Chemical characteristics and origin of clear basal ice facies in dry-based glaciers, South Victoria Land, Antarctica

This paper describes a reconnaissance investigation of the solute chemistry of a clear basal ice facies that previous studies have suggested is the product of accretion of proglacial lake water. Clear basal ice, adjacent englacial ice, lake surface ice and lake water were sampled at six locations in the Taylor and Wright valleys. Ice from each sample location was split into five aliquots and the concentrations of sodium, potassium, calcium, magnesium and chlorides were determined using atomic absorption spectrophotometry. The clear basal ice samples can be divided into three groups on the basis of solute concentrations. Group 1 consists of six samples which have solute concentrations very similar to englacial ice, Group 2 consists of seven samples that have concentrations that are significantly greater than englacial ice and Group 3 consists of one sample which has a solute concentration that is 10 times greater than adjacent englacial ice. Four mechanisms to explain the solute enrichment are examined and it is concluded that although the chemical analysis suggests that some basal ice may have been accreted from proglacial lakes, water chemistry alone is not a reliable indicator of the origin of the clear basal ice.