Conclusions

In studying the hydrological features and imaging the subsurface of Stagnation Glacier with GPR, it has been shown that there is active englacial flow. It was also revealed that the ice core of the east lateral moraine is still connected to the main ice body of the glacier. Englacial conduits extend beyond the edge of the glacier into the buried ice in the surrounding moraines. A spring carrying subglacial water to the surface of the glacier indicates that high hydraulic heads are generated within the glacier.

The presence of caves in the lateral moraine are indicative of preserved relict englacial conduits from periods when the glacier was larger; they have been preserved in the lateral moraine and are occasionally reactivated. The thermal properties of water and the structural and thermal properties of the surrounding ice enable the conduits to be preserved for extended periods of time, depending on the nature of the water flow regime within the conduit. It is also suggested that the routing and preservation of the englacial hydrological system is largely a function of the complex thermal and hydrological setting in polythermal glaciers and the surrounding permafrost. The three dominant controls in conduit preservation within buried ice are their depth beneath the surface, the temperature of the permafrost, and the time since burial. The insulating effect of sediment covering buried ice causes buried ice close to the surface to cool, slowing the rate of creep. Thus the preservation of subsurface conduits is enhanced by the transition from glacial to permafrost terrain.

This research would not have been possible without the field and laboratory assistance of M. Elver, D. Kliza, L. Moorman, C. Deacock, A. Lyttle, J. Williams, F. Walter and T. Irvine-Fynn. The Polar Continental Shelf Project provided logistical assistance for this project. The Northern Science Training Program and the Natural Sciences and Engineering Council of Canada provided financial assistance for field work. The Hamlet of Pond Inlet is acknowledged for their support. Critical review of the manuscript by T. Irvine-Fynn, R. Koerner and an anonymous referee is also very much appreciated and led to the improvement of the text. Finally, the advice, knowledge, friendship and field assistance of F. Michel is very greatly appreciated.

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