Chemical and isotopic characteristics of a glacier-derived naled in front of Austre Gr nfjordbreen, Svalbard

The chemical and stable isotope composition of a glacier-derived naled in front of the glacier Austre Gr nfjordbreen, Svalbard, is examined to elucidate how secondary processes such as preferential retention and leaching affect naled chemistry. Internal candle ice layers have a chemical composition almost similar to that of the lower stratified granular ice layer, whereas the upper granular ice layer has a significantly different composition, which resembles the composition found in glacier meltwater. Grey, platy cryogenic calcite precipitates are found in clusters on the surface of the naled assemblage, indicating preferential retention of Ca2 + and HCO3 . This process is particular pronounced in the distal part of the naled. The isotopic composition in the naled is in accordance with the local meteoric water line and without indications of kinetic fractionation during freezing. The ability to form ice-marginal naled indicates that Austre Gr nfjordbreen has the high meltwater storage potential required for triggering a glacier surge event.