Transient nature of Arctic spring systems driven by subglacial meltwater

Abstract

[1] 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.Citation: Scheidegger, J. M., V. F. Bense, and S. E. Grasby (2012), Transient nature of Arctic spring systems driven by subglacial meltwater, Geophys. Res. Lett., 39, L12405,

Metagenomic evidence for sulfur lithotrophy by Epsilonproteobacteria as the major energy source for primary productivity in a sub-aerial arctic glacial deposit, Borup Fiord Pass

“…The surface of the ice around the spring, and alongside its course, is covered with an elemental sulfur varnish. There is no volcanic or hydrothermal activity in the area that would explain the presence of the sulfur (Grasby et al, 2003) and evidence suggests that the spring is the result of a glacially-driven groundwater system (Grasby et al, 2012; Scheidegger et al, 2012). …”

Impacts of glacially recharged groundwater flow systems on talik evolution

“…Nowadays, a number of numerical modeling codes are capable of considering the impact of ice/water phase changes on groundwater flow. These include, for example, SUTRA‐ICE [ McKenzie et al , ; Ge et al , ], ARCHY [ Rowland et al , ], and FlexPDE [ Bense and Person , ; Bense et al , , ; Scheidegger et al , ]. In this study FlexPDE is used, which is a flexible numerical solution environment for partial differential equations using a scripting language [ PDE Solutions , ].…”

“…Bense et al [] suggest that recharge in a thawing permafrost environment is not sufficient for advective heat flow to have a significant impact on permafrost degradation in a nested groundwater flow system. In contrast, advective heat flow can influence transient taliks, where geothermal heat flow anomalies occur, where flow is strongly focused, or where the recharge is not limited by effective rainfall, such as glacial recharge [ Bense et al , ; Scheidegger et al , ].…”

“…Proglacial areas in front of a wet‐based glacier or an ice sheet could be influenced by groundwater, where subpermafrost groundwater flow is driven by high hydraulic head gradients at the base of the ice sheet. Subglacial‐recharged groundwater flow paths can extend into the proglacial area, where upwelling to the surface can potentially occur via localized high permeability zones [ Boulton et al , ; Piotrowski , ; Grasby et al , ], as observed in springs found in Svalbard [ Haldorsen et al , ] or on Ellesmere Island in the Canadian High Arctic [ Grasby et al , ; Scheidegger et al , ]. The presence of an ice sheet and the ice sheet history influences the hydrogeology, the thermal regime, and isostatic rebound.…”

Geological controls on the present temperature field of the western Sverdrup Basin, Canadian Arctic Archipelago

“…e), subglacial meltwater recharge through the boundary faults or exposed aquifers could have entered the formation pore medium, thus not only lowing the temperature, but also diluting formation water salinity. The existence of modern spring systems in the Sverdrup Basin demonstrates that despite thick permafrost active deep circulation of meteoric water is feasible (Pollard et al ., ; Grasby et al ., , ; Scheidegger et al ., ). Lerche et al .…”