| Summary: | Continental scale glaciations, such as those that covered much of Canada and Northern Europe during the last glacial maximum (26,000 to 19,000 y BP), can be expected to cause large disturbances to both the surficial and subsurface environments. The Greenland Ice Sheet (GrIS) provides a modern, natural analogue for past continental scale glaciations, allowing the extent and nature of the impact on ground and surface waters in the vicinity of the ice sheet to be studied. Currently, geochemical and isotopic information concerning groundwater chemistry and movement adjacent to a continental scale ice sheet is very limited. In areas of continuous permafrost, available knowledge is based on springs, open pingos and fluids from underground openings such as mines. Properly instrumented boreholes can provide additional insight into geochemical processes affecting groundwaters in cryogenic environments next to ice sheets. As part of the Greenland Analogue Project (GAP), three deep, inclined boreholes were drilled in crystalline bedrock in the Kangerlussuaq Region of southwest Greenland and two of these were successfully instrumented with sampling systems: i) Borehole DH-GAP01 intercepting a talik beneath a lake located less than 2 km from the Greenland ice sheet; and ii) Borehole DH-GAP04 was completed adjacent to the ice sheet in order to sample groundwaters from the bedrock below the ice. Drill core from the GAP boreholes was used to study fracture mineralogy, matrix pore fluids and whole rock chemistry. Geochemical studies were conducted on the borehole groundwaters and aimed to determine the depth of meltwater penetration beneath the ice sheet and the relative impact of cryogenic processes such as in-situ freeze out versus water-rock interaction on groundwater salinity. Surface water studies, including lakes and meltwaters in the Kangerlussuaq region, were also undertaken. Understanding the role of taliks, unfrozen conduits through the permafrost, in the groundwater system was an important goal of both surface and ...
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