New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system
This paper presents the first assessment of the Uummannaq ice stream system (UISS) in West Greenland. The UISS drained ~6% of the Greenland ice sheet (GrIS) at the Last Glacial Maximum (LGM). The onset of the UISS is a function of a convergent network of fjords which feed a geologically controlled t...
Published in: | Journal of Geophysical Research: Earth Surface |
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American Geophysical Union
2013
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Online Access: | http://researchonline.ljmu.ac.uk/id/eprint/2502/ https://researchonline.ljmu.ac.uk/id/eprint/2502/3/Roberts_et_al-2013-Journal_of_Geophysical_Research-_Earth_Surface%20%281%29.pdf https://doi.org/10.1002/jgrf.20032 |
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ftliverpooljmu:oai:researchonline.ljmu.ac.uk:2502 2024-09-15T18:09:11+00:00 New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system Roberts, DH Rea, BR Lane, TP Schnabel, C Rodés, A 2013-10-01 text http://researchonline.ljmu.ac.uk/id/eprint/2502/ https://researchonline.ljmu.ac.uk/id/eprint/2502/3/Roberts_et_al-2013-Journal_of_Geophysical_Research-_Earth_Surface%20%281%29.pdf https://doi.org/10.1002/jgrf.20032 en eng American Geophysical Union https://researchonline.ljmu.ac.uk/id/eprint/2502/3/Roberts_et_al-2013-Journal_of_Geophysical_Research-_Earth_Surface%20%281%29.pdf Roberts, DH, Rea, BR, Lane, TP, Schnabel, C and Rodés, A (2013) New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system. Journal of Geophysical Research: Earth Surface, 118 (2). pp. 519-541. ISSN 2169-9011 doi:10.1002/jgrf.20032 GB Physical geography Article PeerReviewed 2013 ftliverpooljmu https://doi.org/10.1002/jgrf.20032 2024-07-11T03:12:58Z This paper presents the first assessment of the Uummannaq ice stream system (UISS) in West Greenland. The UISS drained ~6% of the Greenland ice sheet (GrIS) at the Last Glacial Maximum (LGM). The onset of the UISS is a function of a convergent network of fjords which feed a geologically controlled trough system running offshore to the shelf break. Mapping, cosmogenic radiogenic nuclide (CRN) dating, and model output reveal that glacially scoured surfaces up to 1266 m above sea level (asl) in fjord-head areas were produced by warm-based ice moving offshore during the LGM, with the elevation of warm-based ice dropping westwards to ~700 m asl as the ice stream trunk zone developed. Marginal plateaux with allochthonous blockfields suggest that warm-based ice produced till and erratics up to ~1200 m asl, but CRN ages and weathering pits suggest this was pre-LGM, with only cold-based ice operating during the LGM. Deglaciation began on the outer shelf at ~14.8 cal. kyrs B.P., with Ubekendt Ejland becoming ice free at ~12.4 ka. The UISS then collapsed with over 100 km of retreat by ~11.4 ka–10.8 cal. kyrs B.P., a rapid and complex response to bathymetric deepening, trough widening, and sea-level rise coinciding with rapidly increasing air temperatures and solar radiation, but which occurred prior to ocean warming at ~8.4 cal. kyrs B.P. Local fjord constriction temporarily stabilized the unzipped UISS margins at the start of the Holocene before ice retreat inland of the current margin at ~8.7 ka. Article in Journal/Newspaper Greenland Ice Sheet Uummannaq Liverpool John Moores University: LJMU Research Online Journal of Geophysical Research: Earth Surface 118 2 519 541 |
institution |
Open Polar |
collection |
Liverpool John Moores University: LJMU Research Online |
op_collection_id |
ftliverpooljmu |
language |
English |
topic |
GB Physical geography |
spellingShingle |
GB Physical geography Roberts, DH Rea, BR Lane, TP Schnabel, C Rodés, A New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system |
topic_facet |
GB Physical geography |
description |
This paper presents the first assessment of the Uummannaq ice stream system (UISS) in West Greenland. The UISS drained ~6% of the Greenland ice sheet (GrIS) at the Last Glacial Maximum (LGM). The onset of the UISS is a function of a convergent network of fjords which feed a geologically controlled trough system running offshore to the shelf break. Mapping, cosmogenic radiogenic nuclide (CRN) dating, and model output reveal that glacially scoured surfaces up to 1266 m above sea level (asl) in fjord-head areas were produced by warm-based ice moving offshore during the LGM, with the elevation of warm-based ice dropping westwards to ~700 m asl as the ice stream trunk zone developed. Marginal plateaux with allochthonous blockfields suggest that warm-based ice produced till and erratics up to ~1200 m asl, but CRN ages and weathering pits suggest this was pre-LGM, with only cold-based ice operating during the LGM. Deglaciation began on the outer shelf at ~14.8 cal. kyrs B.P., with Ubekendt Ejland becoming ice free at ~12.4 ka. The UISS then collapsed with over 100 km of retreat by ~11.4 ka–10.8 cal. kyrs B.P., a rapid and complex response to bathymetric deepening, trough widening, and sea-level rise coinciding with rapidly increasing air temperatures and solar radiation, but which occurred prior to ocean warming at ~8.4 cal. kyrs B.P. Local fjord constriction temporarily stabilized the unzipped UISS margins at the start of the Holocene before ice retreat inland of the current margin at ~8.7 ka. |
format |
Article in Journal/Newspaper |
author |
Roberts, DH Rea, BR Lane, TP Schnabel, C Rodés, A |
author_facet |
Roberts, DH Rea, BR Lane, TP Schnabel, C Rodés, A |
author_sort |
Roberts, DH |
title |
New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system |
title_short |
New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system |
title_full |
New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system |
title_fullStr |
New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system |
title_full_unstemmed |
New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system |
title_sort |
new constraints on greenland ice sheet dynamics during the last glacial cycle: evidence from the uummannaq ice stream system |
publisher |
American Geophysical Union |
publishDate |
2013 |
url |
http://researchonline.ljmu.ac.uk/id/eprint/2502/ https://researchonline.ljmu.ac.uk/id/eprint/2502/3/Roberts_et_al-2013-Journal_of_Geophysical_Research-_Earth_Surface%20%281%29.pdf https://doi.org/10.1002/jgrf.20032 |
genre |
Greenland Ice Sheet Uummannaq |
genre_facet |
Greenland Ice Sheet Uummannaq |
op_relation |
https://researchonline.ljmu.ac.uk/id/eprint/2502/3/Roberts_et_al-2013-Journal_of_Geophysical_Research-_Earth_Surface%20%281%29.pdf Roberts, DH, Rea, BR, Lane, TP, Schnabel, C and Rodés, A (2013) New constraints on Greenland ice sheet dynamics during the last glacial cycle: Evidence from the Uummannaq ice stream system. Journal of Geophysical Research: Earth Surface, 118 (2). pp. 519-541. ISSN 2169-9011 doi:10.1002/jgrf.20032 |
op_doi |
https://doi.org/10.1002/jgrf.20032 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
118 |
container_issue |
2 |
container_start_page |
519 |
op_container_end_page |
541 |
_version_ |
1810446612715012096 |