GEOSCAN, résultats de la recherche


TitreTransient nature of Arctic spring systems driven by subglacial meltwater
AuteurScheidegger, J M; Bense, V F; Grasby, S E
SourceGeophysical Research Letters vol. 39, L12405, 2012 p. 1-6,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20120129
Documentpublication en série
Mediapapier; en ligne; numérique
Lat/Long OENS-88.0000 -80.0000 81.0000 80.0000
Sujetschenaux d'eau de fonte; glaciation; glaciers; eau souterraine; mouvement des eaux souterraines; pergélisol; établissement de modèles; géologie des dépôts meubles/géomorphologie; hydrogéologie
Illustrationsmodels; plots
ProgrammeBassin sédimentaire Sverdrup, GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
In the High Arctic, supra- and proglacial springs occur at Borup Fiord Pass, Ellesmere Island. Spring waters are sulfur bearing and isotope analysis suggests springs are fed by deeply circulating glacial meltwater. However, the mechanism maintaining spring flow is unclear in these areas of thick permafrost which would hamper the discharge of deep groundwater to the surface. It has been hypothesized that fracture zones along faults focus groundwater which discharges initially underneath wet-based parts of the ice. With thinning ice, the spring head is exposed to surface temperatures, tens of degrees lower than temperatures of pressure melting, and permafrost starts to develop. Numerical modeling of coupled heat and fluid flow suggest that focused groundwater discharge should eventually be cut off by permafrost encroaching into the feeding channel of the spring. Nevertheless, our model simulations show that these springs can remain flowing for millennia depending on the initial flow rate and ambient surface temperature. These systems might provide a terrestrial analog for the possible occurrence of Martian springs recharged by polar ice caps.