Show simple item record Simon J. en_US David J. en_US Darrel A. en_US Nicholas G. en_US William G. en_US 2011-05-10T15:28:08Z 2011-05-10T15:28:08Z 2011-01-01 en_US
dc.identifier en_US
dc.identifier.citation Cook , S J , Graham , D J , Swift , D A , Midgley , N G & Adam , W G 2011 , ' Sedimentary signatures of basal ice formation and their preservation in ice-marginal sediments ' Geomorphology , vol 125 , no. 1 , pp. 122-131 . , 10.1016/j.geomorph.2010.08.018 en_US
dc.identifier.other PURE: 159394 en_US
dc.identifier.other dspace: 2160/6717 en_US
dc.description.abstract Reconstruction of subglacial processes from sedimentological evidence is central to our understanding of glaciological conditions beneath former ice masses. At Svínafellsjökull, southeast Iceland, we assess the extent to which two different processes of basal ice formation (regelation and glaciohydraulic supercooling) can be identified from ice-marginal sediments. Our results indicate that the sedimentary characteristics of deposits produced by these two processes can be distinguished from one another and that it may be possible to recognise evidence of these processes in Quaternary sediments and to reconstruct their spatial pervasiveness. Sediments derived from the melting of regelation basal ice have (i) a massive structure; (ii) a sediment matrix (0 to 10Ф) dominated by coarse sand; and (iii) a higher proportion of angular clasts than supercool basal ice and associated sediments. Sediments derived from “supercool” basal ice (i) can be either massive or layered; (ii) tend to have a silt-dominated matrix; and (iii) contain a slightly higher proportion of rounded and well-rounded clasts than regelation basal ice and sediments. Previous studies indicate that the dominance of silt within supercool basal ice may be unique to this process, and hence, supercooling should leave a readily recognisable signature in the sedimentary record. Our results from Svínafellsjökull lend support to that idea, although we suggest that further work is required to assess whether silt dominance is a process signature diagnostic of supercooling, and in particular, the extent to which subglacial sediment supply determines the sedimentary character of basal ice facies and associated sediments en_US
dc.format.extent 10 en_US
dc.relation.ispartof Geomorphology en_US
dc.subject basal ice en_US
dc.subject glaciohydraulic supercooling en_US
dc.subject ice-marginal sediments en_US
dc.subject melt-out till en_US
dc.subject quaternary en_US
dc.subject regelation en_US
dc.subject subglacial sediment en_US
dc.title Sedimentary signatures of basal ice formation and their preservation in ice-marginal sediments en_US
dc.contributor.pbl Institute of Geography & Earth Sciences en_US
dc.contributor.pbl Centre for Glaciology en_US

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