CGRG Bibliography of Canadian Geomorphology
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Author : Clarhall, A.
Date : 2002.
Title : Stoss-side moraines, a subglacial landform system. Examples from Baffin Island and northern Sweden.
Publication : Glacial Erosion Zonation - Perspectives on Topography, Landforms, Processes and Time. By: Anders Clarhall. Doctoral Dissertation. Department of Physical Geography and Quaternary Geology, Stockholm University.
Issue : Part IV.
Page(s) : 1-10.
Abstract
Landscapes with a perplexing co-occurrence of glacially eroded and non-eroded surfaces exist in central Baffin Island and northern Sweden. Lakeless, gently undulating areas lacking any significant glacial imprint from the latest period of ice coverage, here called relict surfaces. They occur in higher parts of the terrain and are interpreted to mark areas of sustained frozen bed characteristics. These relict surfaces are interspersed with eroded areas that mark the location of former subglacial melting patches. In zones that must have represented the transition between frozen- and warm-based conditions, a special landform suite occurs. Particular focus is given to the morphology and formation mechanisms of stoss-side moraines, which are deposits on proximal parts of relict surfaces. Geomorphological evidence suggests that redistribution of basal material occurred only within melting patches, which means that the sediment budget in such patches can be regarded as a closed system - entrainment in proximal parts of melting patches and inhibited transport and deposition down-ice where basal temperature changed to freezing. Stoss-side moraines formed where basal temperature changed from melting to freezing and the most plausible explanation for their formation appears to be that frozen basal debris became folded in a zone of longitudinal compression. The deposits are recognized as densely spaced arcuate moraine ridges. In order to preserve the subglacially produced stoss-side moraines and nearby relict surfaces until ice-free conditions existed, melting zone expansion must have ceased. Melting conditions started late during deglaciation as the two described sties. Hence, time for melting zone expansion was limited. Ice divide migration over the areas delayed the start of basal melting further.
Bibliography of Canadian Geomorphology