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Quantification of dead-ice melting in ice-cored moraines at the high-Arctic glacier Holmströmbreen, Svalbard.
- Source :
-
Boreas . May2008, Vol. 37 Issue 2, p211-225. 15p. 4 Color Photographs, 1 Black and White Photograph, 1 Diagram, 3 Graphs, 2 Maps. - Publication Year :
- 2008
-
Abstract
- An extensive dead-ice area has developed at the stagnant snout of the Holmströmbreen glacier, Svalbard, following its last advance during the Little Ice Age (LIA). The most common landform is ice-cored slopes hosting sediment gravity flows. Dead-ice melting is described and quantified through field studies and analyses of high-resolution, multi-temporal aerial photographs and QuickBird 2 satellite imagery. Field measurements of backwasting of ice-cored slopes indicate melting rates of 9.2 cm/day. Downwasting rates reveal a dead-ice surface lowering of 0.9 m/yr from 1984 to 2004. The volume of melted dead-ice in the marginal zone since the LIA is estimated at 2.72 km3. Most prominently, dead-ice melting causes the growth of an ice-walled lake with an area increasing near-exponentially over the last 40 years. Despite the high-Arctic setting, dead-ice melting progresses with similar rates as in humid sub-polar climates, stressing that melt rates are governed by processes and topography rather than climate. We suggest that the permafrost and lack of glacier karst prevent meltwater percolation, thus maintaining a liquefied debris-cover where new dead-ice is continuously exposed to melting. As long as backwasting and mass movement processes prevent build-up of an insulating debris-cover, the de-icing continues despite the continuous permafrost. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 03009483
- Volume :
- 37
- Issue :
- 2
- Database :
- Academic Search Index
- Journal :
- Boreas
- Publication Type :
- Academic Journal
- Accession number :
- 34185251
- Full Text :
- https://doi.org/10.1111/j.1502-3885.2007.00014.x