Geochemistry of groundwater in front of a warm‐based glacier in southeast greenland

Abstract

Groundwater in front of warm‐based glaciers is likely to become a more integrated part of the future proglacial hydrological system at high latitudes due to global warming. Here, we present the first monitoring results of shallow groundwater chemistry and geochemical fingerprinting of glacier meltwater in front of a warm‐based glacier in outheast reenland (ittivakkat letscher, 65° 41′ , 37° 48′ ). The groundwater temperature, electrical conductivity and pressure head were monitored from ugust 2009 to ugust 2011, and water samples were collected in 2009 and analyzed for major ions and water isotopes (δD, δ18O). The 2-yrs of monitoring revealed that major outbursts of glacier water during the ablation season flushed the proglacial aquifer and determined the groundwater quality for the next 2–8 weeks until stable chemical conditions were reached again. Water isotope composition shows that isotopic fractionation occurs in both groundwater and glacier meltwater, but fractionation due to evaporation from near‐surface soil moisture prior to infiltration has the most significant effect. This study shows that groundwater in ow rctic reenland is likely to possess a combined geochemical and isotopic composition, which is distinguishable from other water sources in the proglacial environment. However, the shallow groundwater composition at a given time is highly dependent on major outbursts of glacier water in the previous months.