Show simple item record Maarten en_US Neil Franklin en_US 2011-10-25T11:57:18Z 2011-10-25T11:57:18Z 2011-07 en_US
dc.identifier en_US
dc.identifier.citation Krabbendam , M & Glasser , N F 2011 , ' Glacial erosion and bedrock properties in NW Scotland: Abrasion and plucking, hardness and joint spacing ' Geomorphology , vol 130 , no. 3-4 , pp. 374-383 . , 10.1016/j.geomorph.2011.04.022 en_US
dc.identifier.other PURE: 172048 en_US
dc.identifier.other dspace: 2160/7618 en_US
dc.description.abstract Subglacial erosion beneath glaciers occurs predominantly by abrasion and plucking, producing distinct erosional forms. The controls on the relative importance of abrasion vs. plucking are poorly understood. On the one hand, glacial conditions that favour or suppress cavity formation (ice velocity, ice thickness, and water pressure) are thought to favour plucking or abrasion, respectively. Conversely, bedrock properties are also known to control landforms, but this has rarely been analysed quantitatively. In this study we compare landforms and bedrock properties of sandstone and quartzite at the bed of a palaeo-ice stream near Ullapool in NW Scotland. The boundary between the rock types is at right angles to the westward palaeo-ice flow, and palaeoglacial conditions on both rock types were similar. We report quantitative parameters for bedrock properties (Schmidt hammer hardness and joint spacing) and use morphometric parameters to analyse the landforms. Torridon sandstone is soft but thick-bedded and with a wide joint spacing. Erosional bedforms include roche moutonnees with smoothed tops and concave stoss sides, whalebacks, and elongate p-forms, indicating a high proportion of abrasion over plucking. Cambrian quartzite is hard but thin-bedded with narrow joint spacing. Erosional landforms are angular to subangular with abundant plucked lee faces, suggesting a high proportion of plucking over abrasion. Hardness and joint spacing thus exert a strong control on subglacial erosional landforms and the mechanisms that formed them. Thus glacial conditions (ice velocity, ice thickness) can only be inferred from glacial erosional landforms if the effects of bedrock properties of the substrate are considered. (C) 2011 Published by Elsevier B.V. en_US
dc.format.extent 10 en_US
dc.relation.ispartof Geomorphology en_US
dc.subject Glacial erosion en_US
dc.subject Bedrock en_US
dc.subject Abrasion en_US
dc.subject Plucking en_US
dc.subject Whaleback en_US
dc.title Glacial erosion and bedrock properties in NW Scotland: Abrasion and plucking, hardness and joint spacing en_US
dc.contributor.pbl Centre for Glaciology en_US
dc.contributor.pbl Institute of Geography & Earth Sciences en_US

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