Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates
The Greenland Ice Sheet is a key contributor to contemporary global sea level rise, but its long-term history and response to episodes of warming in Earth’s geological past remain uncertain. The terrain covered by the ice sheet comprises ~79 % of Greenland and ~1.1 % of the Earth’s land surface and...
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Copernicus Publications
2023
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00069718 2023-12-10T09:48:16+01:00 Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates Paxman, Guy J. G. Jamieson, Stewart S. R. Dolan, Aisling M. Bentley, Michael J. 2023-11 electronic https://doi.org/10.5194/egusphere-2023-2502 https://noa.gwlb.de/receive/cop_mods_00069718 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068093/egusphere-2023-2502.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2502/egusphere-2023-2502.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2023-2502 https://noa.gwlb.de/receive/cop_mods_00069718 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068093/egusphere-2023-2502.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2502/egusphere-2023-2502.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2023 ftnonlinearchiv https://doi.org/10.5194/egusphere-2023-2502 2023-11-13T00:22:47Z The Greenland Ice Sheet is a key contributor to contemporary global sea level rise, but its long-term history and response to episodes of warming in Earth’s geological past remain uncertain. The terrain covered by the ice sheet comprises ~79 % of Greenland and ~1.1 % of the Earth’s land surface and contains geomorphological records that may provide valuable insights into past ice-sheet behaviour. Here we use ice surface morphology and radio-echo sounding data to identify ice-covered valleys within the highlands of southern and eastern Greenland and use numerical ice-sheet modelling to constrain the climatological and glaciological conditions responsible for valley incision. Our mapping reveals intricate subglacial valley networks with morphologies that are indicative of substantial glacial modification of an inherited fluvial landscape, yet many of these valleys are presently situated beneath cold-based, slow-moving (i.e., non-erosive) ice. We use the morphology of the valleys and our simple ice-sheet model experiments to infer that incision likely occurred beneath erosive mountain valley glaciers during one or more phases of Greenland’s glacial history when ice was restricted to the southern and eastern highlands, and Greenland’s contribution to barystatic sea level was up to +7 metres relative to today. We infer that this valley incision primarily occurred prior to the growth of a continental-scale ice sheet, most likely during the late Miocene (ca. 7–5 Ma) and/or late Pliocene (ca. 3.6–2.6 Ma). Our findings therefore provide new data-based constraints on early Greenland Ice Sheet extent and dynamics that can serve as valuable boundary conditions in models of regional and global palaeoclimate during past warm periods that are important analogues for the 21st Century and beyond. Article in Journal/Newspaper East Greenland Greenland Ice Sheet Niedersächsisches Online-Archiv NOA Greenland |
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Open Polar |
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Niedersächsisches Online-Archiv NOA |
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ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Paxman, Guy J. G. Jamieson, Stewart S. R. Dolan, Aisling M. Bentley, Michael J. Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates |
topic_facet |
article Verlagsveröffentlichung |
description |
The Greenland Ice Sheet is a key contributor to contemporary global sea level rise, but its long-term history and response to episodes of warming in Earth’s geological past remain uncertain. The terrain covered by the ice sheet comprises ~79 % of Greenland and ~1.1 % of the Earth’s land surface and contains geomorphological records that may provide valuable insights into past ice-sheet behaviour. Here we use ice surface morphology and radio-echo sounding data to identify ice-covered valleys within the highlands of southern and eastern Greenland and use numerical ice-sheet modelling to constrain the climatological and glaciological conditions responsible for valley incision. Our mapping reveals intricate subglacial valley networks with morphologies that are indicative of substantial glacial modification of an inherited fluvial landscape, yet many of these valleys are presently situated beneath cold-based, slow-moving (i.e., non-erosive) ice. We use the morphology of the valleys and our simple ice-sheet model experiments to infer that incision likely occurred beneath erosive mountain valley glaciers during one or more phases of Greenland’s glacial history when ice was restricted to the southern and eastern highlands, and Greenland’s contribution to barystatic sea level was up to +7 metres relative to today. We infer that this valley incision primarily occurred prior to the growth of a continental-scale ice sheet, most likely during the late Miocene (ca. 7–5 Ma) and/or late Pliocene (ca. 3.6–2.6 Ma). Our findings therefore provide new data-based constraints on early Greenland Ice Sheet extent and dynamics that can serve as valuable boundary conditions in models of regional and global palaeoclimate during past warm periods that are important analogues for the 21st Century and beyond. |
format |
Article in Journal/Newspaper |
author |
Paxman, Guy J. G. Jamieson, Stewart S. R. Dolan, Aisling M. Bentley, Michael J. |
author_facet |
Paxman, Guy J. G. Jamieson, Stewart S. R. Dolan, Aisling M. Bentley, Michael J. |
author_sort |
Paxman, Guy J. G. |
title |
Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates |
title_short |
Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates |
title_full |
Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates |
title_fullStr |
Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates |
title_full_unstemmed |
Subglacial valleys preserved in the highlands of south and east Greenland record restricted ice extent during past warmer climates |
title_sort |
subglacial valleys preserved in the highlands of south and east greenland record restricted ice extent during past warmer climates |
publisher |
Copernicus Publications |
publishDate |
2023 |
url |
https://doi.org/10.5194/egusphere-2023-2502 https://noa.gwlb.de/receive/cop_mods_00069718 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068093/egusphere-2023-2502.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2502/egusphere-2023-2502.pdf |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
East Greenland Greenland Ice Sheet |
genre_facet |
East Greenland Greenland Ice Sheet |
op_relation |
https://doi.org/10.5194/egusphere-2023-2502 https://noa.gwlb.de/receive/cop_mods_00069718 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00068093/egusphere-2023-2502.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2502/egusphere-2023-2502.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/egusphere-2023-2502 |
_version_ |
1784892201551003648 |