Possible groundwater dominance in the subglacial hydrology of ice sheet interiors: example at Dome C, East Antarctica

Abstract

We hypothesize that groundwater systems may be the main water transport mechanism over (distributed, inefficient) water sheets at large scales in the interiors of ice sheets where melt rates are very low. We compare melt rate magnitudes to potential groundwater volume fluxes and also calculate the theoretical transmissivity ranges of subglacial water sheet and groundwater flow systems. Theoretical groundwater systems are on par with or are more transmissive than water sheets for the upper half of the permeability spectrum. In addition, we develop a 2D cross-sectional subglacial flow path model that connects subglacial lakes near Dome C, East Antarctica. This model integrates subglacial water sheet flux and hypothetical groundwater flow forcing, better bridging two historically disparate modeling frameworks – subglacial hydrology and ice sheet hydrogeology. Our model results suggest that the water sheet thickness can be highly dependent on groundwater flux and that the water sheet transmissivity is within the total range of the modeled groundwater system transmissivity. We infer from these results that subglacial lake stability and basal radar reflections underneath the interior of East Antarctica may possibly be affected by groundwater flow.