CGRG Bibliography of Canadian Geomorphology
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Author : De Angelis, H.; and Kleman, J
Date : 2005.
Title : Palaeo-ice streams in the Foxe/Baffin sector of the Laurentide ice sheet.
Publication : Nordic Glaciology. Extended Abstracts of the International Glaciological Society Nordic Branch Meeting. 2-5 November 2005. Edited by Ahlstrøm, A.P. and Bøggild, C.E. Geological Survey of Denmark and Greenland Report
Issue : 2005/67:
Page(s) : 7.
Abstract
Ice streams are essential components of ice sheets. Observations on present ice sheets indicate that the bulk of ice is exported off through networks of ice streams and palaeoglaciological evidence shows that ancient ice sheets behaved in a similar manner. Furthermore, ice stream networks are prone to changes and reorganization which may lead to variations in the ice export rate of ice sheets, affecting the oceanic circulation and ultimately the climate. In fact, major reorganizations of the ice streams of the Laurentide Ice Sheet (LIS) have been invoked to explain the existence of ice-rafted debris layers in the North Atlantic and Arctic Oceans and the associated climate excursions. Accurate and complete palaeoglaciological reconstructions of the LIS are therefore important for a better understanding of these events and to evaluate the consequences of possible future scenarios. The Palaeoglaciology Group at Stockholm University is actively working to produce a complete palaeoglaciological picture of the LIS, focusing in particular to the accurate depiction of palaeo-ice stream networks and their changes. In the framework of this activity, we here present mapping of palaeo-ice streams in the portion of the Canadian Arctic formerly covered by the Foxe/Baffin sector of the LIS. The Foxe/Baffin was a dynamically important portion because of its critical location at the north Atlantic side of the ice sheet. In this region, several palaeo-ice streams have been described but a comprehensive palaeo-ice stream map was never constructed. Our work is largely based on the geomorphological interpretation of 68 Landsat ETM+ scenes, in combination with digital elevation models, multibeam sonar surveys and published reconstructions. The interpretation of the resulting map of glacial landforms was guided by a glaciological inversion scheme, i.e. a model which formalizes the procedure of using the landform record for the reconstruction of palaeo-ice sheets. The location and geometry of palaeo-ice streams and palaeo-frozen bed zones were interpreted according to published criteria for their recognition in the landform record. Our results show that the Foxe/Baffin sector was drained by a system of outlet glaciers and ice streams that underwent marked changes during deglaciation. One of the most remarkable aspects of this is the occurrence of transient ice streams in topographically defined corridors, in particular in northern Baffin Island. Large areas of Melville Peninsula and central Baffin Island were subject to cold-based conditions, leading to preservation of ancient landscapes. In other sectors, mosaics of such preserved patches, and patches suggesting basal sliding and thawed-bed conditions, can be deciphered to reconstruct local histories of changing basal thermal conditions. Finally, we found that the landform archive along the Hudson Strait does not conclusively support the existence of an ice stream in that location. In our opinion, considering the relevance of this topographic through as a potential ice export channel, a thorough reanalysis of the evidence for an ice stream along the Hudson Strait is urgently needed.
Bibliography of Canadian Geomorphology