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Glacial landscape evolution in the Uummannaq region, West Greenland


Lane, Timothy P; Roberts, David H; Ó Cofaigh, Colm; Rea, Brice R; Vieli, Andreas (2016). Glacial landscape evolution in the Uummannaq region, West Greenland. Boreas, 45(2):220-234.

Abstract

The Uummannaq region is a mosaic of glacial landsystems, consistent with hypothesized landscape distributionresulting from variations in subglacial thermal regime. The region is dominated by selective linear erosion that hasspatially and altitudinally partitioned the landscape. Low altitude areas are dominated by glacial scour and higherelevations are dominated by plateaux or mountain valley and cirque glaciers. The appearance and nature of eachlandscape type varies locally with altitude and latitude, as a function of bedrock geology and average glacial con-ditions. Selective linear erosion has been a primary control on landscape distribution throughout Uummannaq,leading to plateau formation and the growth of a coalescent fjord system in the Uummannaq region. This hasallowed the development of the Uummannaq ice stream’s (UIS) onset zone during glacial periods. Fjord develop-ment has been enhanced by a downstream change in geology to less-resistant lithologies, increasing erosional effi-ciency and allowing a single glacial channel to develop, encouraging glacier convergence and the initiation of icestreaming. The landscape has been affected by several periods of regional uplift from 33 Ma to present, and hasbeen subject to subsequent fluvial and glacial erosion. Uplift has removed surfaces from the impact of widespreadwarm-based glaciation, leaving them as relict landsurfaces. The result of this is a regional altitude-dependent con-tinuum of glacial modification, with extreme differences in erosion between high and low elevation surfaces. Thisstudy indicates that processes of long-term uplift, glacial erosion/protection and spatial variability in erosionintensity have produced a highly partitioned landscape.

Abstract

The Uummannaq region is a mosaic of glacial landsystems, consistent with hypothesized landscape distributionresulting from variations in subglacial thermal regime. The region is dominated by selective linear erosion that hasspatially and altitudinally partitioned the landscape. Low altitude areas are dominated by glacial scour and higherelevations are dominated by plateaux or mountain valley and cirque glaciers. The appearance and nature of eachlandscape type varies locally with altitude and latitude, as a function of bedrock geology and average glacial con-ditions. Selective linear erosion has been a primary control on landscape distribution throughout Uummannaq,leading to plateau formation and the growth of a coalescent fjord system in the Uummannaq region. This hasallowed the development of the Uummannaq ice stream’s (UIS) onset zone during glacial periods. Fjord develop-ment has been enhanced by a downstream change in geology to less-resistant lithologies, increasing erosional effi-ciency and allowing a single glacial channel to develop, encouraging glacier convergence and the initiation of icestreaming. The landscape has been affected by several periods of regional uplift from 33 Ma to present, and hasbeen subject to subsequent fluvial and glacial erosion. Uplift has removed surfaces from the impact of widespreadwarm-based glaciation, leaving them as relict landsurfaces. The result of this is a regional altitude-dependent con-tinuum of glacial modification, with extreme differences in erosion between high and low elevation surfaces. Thisstudy indicates that processes of long-term uplift, glacial erosion/protection and spatial variability in erosionintensity have produced a highly partitioned landscape.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Date:2016
Deposited On:11 Jan 2017 15:37
Last Modified:11 Jan 2017 15:38
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0300-9483
Publisher DOI:https://doi.org/10.1111/bor.12150

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