Palaeohydrology of Kangerlussuaq (Søndre Strømfjord), West Greenland during the last ~8000 years

Abstract

Major fluctuations of hydroclimate in West Greenland are recorded in palaeoshoreline terraces that encircle several lakes near Kangerlussuaq, Greenland (67°01′N, 50°40′W). Geomorphic and stratigraphic analyses were used to construct a lake-level curve for Hunde Sø, a large closed-basin lake in this region. Changes in lake volume associated with lake-level fluctuations were calculated, and a water-balance model was used to determine the primary factors influencing lake volume and the changes in those factors necessary to affect reconstructed lake-level change. Sensitivity tests suggest that mean annual precipitation and the relative proportion of summer versus winter precipitation are the primary climate drivers of lake-level change. Temperature effects are less important unless coupled with changes in one of the other variables. Two pluvial periods occurred centred around 4600 and 2000 cal. yr BP, with mean annual precipitation estimated at 130 mm and 70 mm higher than modern, respectively. In contrast, a low-stand prior to 6070 cal. yr BP with water levels as much as 18 m below modern was a result of summer temperatures ~ 2—3° above modern, coupled with a 14 day increase in the length of the ice-off period and a reduction in mean annual precipitation of ~80 mm relative to modern.