Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland.
Recent work has confirmed that grounded ice reached the shelf break in central West Greenland during the Last Glacial Maximum (LGM). Here we use a combination of marine sediment-core data, including glacimarine lithofacies and IRD proxy records, and geomorphological and acoustic facies evidence to e...
Published in: | Quaternary Science Reviews |
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Elsevier
2016
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Online Access: | http://dro.dur.ac.uk/18138/ http://dro.dur.ac.uk/18138/1/18138.pdf http://dro.dur.ac.uk/18138/2/18138.pdf http://dro.dur.ac.uk/18138/3/18138P.pdf https://doi.org/10.1016/j.quascirev.2016.01.018 |
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ftunivdurham:oai:dro.dur.ac.uk.OAI2:18138 2023-05-15T16:27:48+02:00 Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland. Hogan, K.A. Ó Cofaigh, C. Jennings, A.E. Dowdeswell, J.A. Hiemstra, J.F. 2016-09-01 application/pdf http://dro.dur.ac.uk/18138/ http://dro.dur.ac.uk/18138/1/18138.pdf http://dro.dur.ac.uk/18138/2/18138.pdf http://dro.dur.ac.uk/18138/3/18138P.pdf https://doi.org/10.1016/j.quascirev.2016.01.018 unknown Elsevier dro:18138 issn:0277-3791 doi:10.1016/j.quascirev.2016.01.018 http://dro.dur.ac.uk/18138/ http://dx.doi.org/10.1016/j.quascirev.2016.01.018 http://dro.dur.ac.uk/18138/1/18138.pdf http://dro.dur.ac.uk/18138/2/18138.pdf http://dro.dur.ac.uk/18138/3/18138P.pdf © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). CC-BY Quaternary science reviews, 2016, Vol.147, pp.5-26 [Peer Reviewed Journal] Article PeerReviewed 2016 ftunivdurham https://doi.org/10.1016/j.quascirev.2016.01.018 2020-05-28T22:34:31Z Recent work has confirmed that grounded ice reached the shelf break in central West Greenland during the Last Glacial Maximum (LGM). Here we use a combination of marine sediment-core data, including glacimarine lithofacies and IRD proxy records, and geomorphological and acoustic facies evidence to examine the nature of and controls on the retreat of a major outlet of the western sector of the Greenland Ice Sheet (GrIS) across the shelf. Retreat of this outlet, which contained the ancestral Jakobshavns Isbræ ice stream, from the outer shelf in Disko Trough was rapid and progressed predominantly through iceberg calving, however, minor pauses in retreat (tens of years) occurred on the middle shelf at a trough narrowing forming subtle grounding-zone wedges. By 12.1 cal kyr BP ice had retreated to a basalt escarpment and shallow banks on the inner continental shelf, where it was pinned and stabilised for at least 100 years. During this time the ice margin appears to have formed a calving bay over the trough and melting became an important mechanism of ice-mass loss. Fine-grained sediments (muds) were deposited alternately with IRD-rich sediments (diamictons) forming a characteristic deglacial lithofacies that may be related to seasonal climatic cycles. High influxes of subglacial meltwater, emanating from the nearby ice margins, deposited muddy sediments during the warmer summer months whereas winters were dominated by iceberg calving leading to the deposition of the diamictons. This is the first example of this glacimarine lithofacies from a continental-shelf setting and we suggest that the calving-bay configuration of the ice margin, plus the switching between calving and melting as ablation mechanisms, facilitated its deposition by channelling meltwater and icebergs through the inner trough. The occurrence of a major stillstand on the inner shelf in Disko Trough demonstrates that the ice-dynamical response to local topography was a crucial control on the behaviour of a major outlet in this sector of the GrIS during retreat. Article in Journal/Newspaper Greenland Ice Sheet Durham University: Durham Research Online Greenland Quaternary Science Reviews 147 5 26 |
institution |
Open Polar |
collection |
Durham University: Durham Research Online |
op_collection_id |
ftunivdurham |
language |
unknown |
description |
Recent work has confirmed that grounded ice reached the shelf break in central West Greenland during the Last Glacial Maximum (LGM). Here we use a combination of marine sediment-core data, including glacimarine lithofacies and IRD proxy records, and geomorphological and acoustic facies evidence to examine the nature of and controls on the retreat of a major outlet of the western sector of the Greenland Ice Sheet (GrIS) across the shelf. Retreat of this outlet, which contained the ancestral Jakobshavns Isbræ ice stream, from the outer shelf in Disko Trough was rapid and progressed predominantly through iceberg calving, however, minor pauses in retreat (tens of years) occurred on the middle shelf at a trough narrowing forming subtle grounding-zone wedges. By 12.1 cal kyr BP ice had retreated to a basalt escarpment and shallow banks on the inner continental shelf, where it was pinned and stabilised for at least 100 years. During this time the ice margin appears to have formed a calving bay over the trough and melting became an important mechanism of ice-mass loss. Fine-grained sediments (muds) were deposited alternately with IRD-rich sediments (diamictons) forming a characteristic deglacial lithofacies that may be related to seasonal climatic cycles. High influxes of subglacial meltwater, emanating from the nearby ice margins, deposited muddy sediments during the warmer summer months whereas winters were dominated by iceberg calving leading to the deposition of the diamictons. This is the first example of this glacimarine lithofacies from a continental-shelf setting and we suggest that the calving-bay configuration of the ice margin, plus the switching between calving and melting as ablation mechanisms, facilitated its deposition by channelling meltwater and icebergs through the inner trough. The occurrence of a major stillstand on the inner shelf in Disko Trough demonstrates that the ice-dynamical response to local topography was a crucial control on the behaviour of a major outlet in this sector of the GrIS during retreat. |
format |
Article in Journal/Newspaper |
author |
Hogan, K.A. Ó Cofaigh, C. Jennings, A.E. Dowdeswell, J.A. Hiemstra, J.F. |
spellingShingle |
Hogan, K.A. Ó Cofaigh, C. Jennings, A.E. Dowdeswell, J.A. Hiemstra, J.F. Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland. |
author_facet |
Hogan, K.A. Ó Cofaigh, C. Jennings, A.E. Dowdeswell, J.A. Hiemstra, J.F. |
author_sort |
Hogan, K.A. |
title |
Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland. |
title_short |
Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland. |
title_full |
Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland. |
title_fullStr |
Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland. |
title_full_unstemmed |
Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland. |
title_sort |
deglaciation of a major palaeo-ice stream in disko trough, west greenland. |
publisher |
Elsevier |
publishDate |
2016 |
url |
http://dro.dur.ac.uk/18138/ http://dro.dur.ac.uk/18138/1/18138.pdf http://dro.dur.ac.uk/18138/2/18138.pdf http://dro.dur.ac.uk/18138/3/18138P.pdf https://doi.org/10.1016/j.quascirev.2016.01.018 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_source |
Quaternary science reviews, 2016, Vol.147, pp.5-26 [Peer Reviewed Journal] |
op_relation |
dro:18138 issn:0277-3791 doi:10.1016/j.quascirev.2016.01.018 http://dro.dur.ac.uk/18138/ http://dx.doi.org/10.1016/j.quascirev.2016.01.018 http://dro.dur.ac.uk/18138/1/18138.pdf http://dro.dur.ac.uk/18138/2/18138.pdf http://dro.dur.ac.uk/18138/3/18138P.pdf |
op_rights |
© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.quascirev.2016.01.018 |
container_title |
Quaternary Science Reviews |
container_volume |
147 |
container_start_page |
5 |
op_container_end_page |
26 |
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1766017317713477632 |