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| Titel |
Longitudinal surface structures (flowstripes) on Antarctic glaciers |
| VerfasserIn |
N. F. Glasser, G. H. Gudmundsson |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 6, no. 2 ; Nr. 6, no. 2 (2012-03-30), S.383-391 |
| Datensatznummer |
250003486
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| Publikation (Nr.) |
 copernicus.org/tc-6-383-2012.pdf |
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| Zusammenfassung |
| Longitudinal surface structures ("flowstripes") are common on many
glaciers but their origin and significance are poorly understood. In this
paper we present observations of the development of these longitudinal
structures from four different Antarctic glacier systems; the Lambert
Glacier/Amery Ice Shelf area, the Taylor and Ferrar Glaciers in the Ross Sea
sector, Crane and Jorum Glaciers (ice-shelf tributary glaciers) on the
Antarctic Peninsula, and the onset zone of a tributary to the Recovery
Glacier Ice Stream in the Filchner Ice Shelf area. Mapping from optical
satellite images demonstrates that longitudinal surface structures develop
in two main situations: (1) as relatively wide flow stripes within glacier
flow units and (2) as relatively narrow flow stripes where there is
convergent flow around nunataks or at glacier confluence zones. Our
observations indicate that the confluence features are narrower, sharper,
and more clearly defined features. They are characterised by linear troughs
or depressions on the ice surface and are much more common than the former
type. Longitudinal surface structures within glacier flow units have
previously been explained as the surface expression of localised bed
perturbations but a universal explanation for those forming at glacier
confluences is lacking. Here we propose that these features are formed at
zones of ice acceleration and extensional flow at glacier confluences. We
provide a schematic model for the development of longitudinal surface
structures based on extensional flow that can explain their ridge and trough
morphology as well as their down-ice persistence. |
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