GEOCHEMICAL AND ISOTOPIC CHARACTERIZATION OF SURFACE AND GROUND WATER FROM AN AREA OF CONTINUOUS PERMAFROST ADJACENT TO THE GREENLAND ICE SHEET, KANGERLUSSUAQ, GREENLAND

Surface waters in the Kangerlussuaq region, Western Greenland, were characterized using chemical and isotopic data based on samples acquired in the summers of 2008 and 2009. The objective was to establish a basic concept of water chemistry and geochemical processes in the permafrost impacted region. This surface water study was preliminary work for a larger drilling project aimed to further understanding of hydrogeochemistry and groundwater flow beneath ice sheets. Field studies of the interaction between ice sheets and groundwater are essential for resolving some of the uncertainties in current ice sheet models developed for radioactive waste disposal programs. Samples collected from lakes, glacial meltwater, a borehole drilled into a talik and a spring were analyzed for ¹⁸O, ²H and ³H and a smaller subset of samples analyzed for ^87/86Sr, ³⁴S/¹⁸O (SO₄), and ³⁷Cl.

Based on these data surface water chemistries were observed to be influenced by a variety of factors including evaporation, sea salt aerosols, elevation, geology, groundwater and freezing processes. ¹⁸O and ²H showed most samples falling along a local meteoric water line with modern tritium values, the most notable exceptions being the heavily depleted glacial meltwater and the depleted spring water. The presence of pressurized, meltwater systems operating along fault lines was examined based on chemical and isotopic data.

Of special interest was the warm, mineralized spring located in front of the ice sheet. The chemistry of this pro-glacial spring has remained stable since it was previously sampled by Scholz and Baumann (1997). Tritium values and depleted ¹⁸O and ²H suggest a component of glacial meltwater. ³⁴S¹⁸O₄ suggests the possibility of bacterial reduction.

References

Herbert Scholz and Manfred Baumann, 1997. An ‘open system pingo’ near Kangerlussuaq (Sondre Stromfjord), West Greenland. Geology of Greenland Survey Bulletin, (176), 104-108.