Glacier-permafrost hydrology interactions, Bylot Island, Canada

A temporal study of perennial groundwater springs, icings, lee caves and subsurface tunnels demonstrates the complex interactions between glacial and terrestrial hydrology on Bylot Island, Canada. Thermal and ground-penetrating radar analysis show that the portions of the island not covered by glaciers are underlain by continuous permafrost, while some of the glaciers appear to be polythermal with subglacial taliks. Hydrological observations indicate that taliks generated beneath glaciers can extend beyond the glacial limits, thus modifying the surrounding terrestrial hydrological system. An icing that varies in size annually was found to result from the draining of a large tunnel complex that extended from within a glacier out into the surrounding lateral moraine. Nearby, a large perennial icing grew from water flow through a subglacial talik originating beneath an ice-dammed lake. In both these cases it was found that the subsurface hydrological system was a continuum between the glacial and periglacial environments.