Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow
The land-terminating margin of the Greenland Ice Sheet has slowed down in recent decades, although the causes and implications for future ice flow are unclear. Explained originally by a self-regulating mechanism where basal slip reduces as drainage evolves from low to high efficiency, recent numeric...
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Uppsala universitet, Luft-, vatten- och landskapslära
2017
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ftuppsalauniv:oai:DiVA.org:uu-336647 2023-05-15T16:27:11+02:00 Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow Kulessa, Bernd Hubbard, Alun L. Booth, Adam D. Bougamont, Marion Dow, Christine F. Doyle, Samuel H. Christoffersen, Poul Lindback, Katrin Pettersson, Rickard Fitzpatrick, Andrew A. W. Jones, Glenn A. 2017 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-336647 https://doi.org/10.1126/sciadv.1603071 eng eng Uppsala universitet, Luft-, vatten- och landskapslära Swansea Univ, Glaciol Grp, Coll of Sci UiT Arctic Univ Norway, Ctr Arctic Gas Hydrate Environm & Climate, Dept Geosci.; Aberystwyth Univ, Ctr Glaciol, Dept Geog & Earth Sci Univ Leeds, Inst Appl Geosci, Sch Earth & Environm Univ Cambridge, Scott Polar Res Inst, Dept Geog Swansea Univ, Glaciol Grp, Coll Sci, Singleton Pk.; Univ Waterloo, Dept Geog & Environm Management Aberystwyth Univ, Ctr Glaciol, Dept Geog & Earth Sci Norwegian Polar Res Inst, Fram Ctr Swansea Univ, Glaciol Grp, Coll of Sci.; Aberystwyth Univ, Ctr Glaciol, Dept Geog & Earth Sci Science Advances, 2017, 3:8, http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-336647 doi:10.1126/sciadv.1603071 ISI:000411589900043 info:eu-repo/semantics/openAccess Earth and Related Environmental Sciences Geovetenskap och miljövetenskap Physical Geography Naturgeografi Oceanography Hydrology and Water Resources Oceanografi hydrologi och vattenresurser Article in journal info:eu-repo/semantics/article text 2017 ftuppsalauniv https://doi.org/10.1126/sciadv.1603071 2023-02-23T21:52:24Z The land-terminating margin of the Greenland Ice Sheet has slowed down in recent decades, although the causes and implications for future ice flow are unclear. Explained originally by a self-regulating mechanism where basal slip reduces as drainage evolves from low to high efficiency, recent numerical modeling invokes a sedimentary control of ice sheet flow as an alternative hypothesis. Although both hypotheses can explain the recent slowdown, their respective forecasts of a long-term deceleration versus an acceleration of ice flow are contradictory. We present amplitude-versus-angle seismic data as the first observational test of the alternative hypothesis. We document transient modifications of basal sediment strengths by rapid subglacial drainages of supraglacial lakes, the primary current control on summer ice sheet flow according to our numerical model. Our observations agree with simulations of initial postdrainage sediment weakening and ice flow accelerations, and subsequent sediment restrengthening and ice flow decelerations, and thus confirm the alternative hypothesis. Although simulated melt season acceleration of ice flow due to weakening of subglacial sediments does not currently outweigh winter slowdown forced by self regulation, they could dominate over the longer term. Subglacial sediments beneath the Greenland Ice Sheet must therefore be mapped and characterized, and a sedimentary control of ice flow must be evaluated against competing self-regulation mechanisms. Article in Journal/Newspaper Greenland Ice Sheet Uppsala University: Publications (DiVA) Greenland Science Advances 3 8 e1603071 |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Earth and Related Environmental Sciences Geovetenskap och miljövetenskap Physical Geography Naturgeografi Oceanography Hydrology and Water Resources Oceanografi hydrologi och vattenresurser |
spellingShingle |
Earth and Related Environmental Sciences Geovetenskap och miljövetenskap Physical Geography Naturgeografi Oceanography Hydrology and Water Resources Oceanografi hydrologi och vattenresurser Kulessa, Bernd Hubbard, Alun L. Booth, Adam D. Bougamont, Marion Dow, Christine F. Doyle, Samuel H. Christoffersen, Poul Lindback, Katrin Pettersson, Rickard Fitzpatrick, Andrew A. W. Jones, Glenn A. Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow |
topic_facet |
Earth and Related Environmental Sciences Geovetenskap och miljövetenskap Physical Geography Naturgeografi Oceanography Hydrology and Water Resources Oceanografi hydrologi och vattenresurser |
description |
The land-terminating margin of the Greenland Ice Sheet has slowed down in recent decades, although the causes and implications for future ice flow are unclear. Explained originally by a self-regulating mechanism where basal slip reduces as drainage evolves from low to high efficiency, recent numerical modeling invokes a sedimentary control of ice sheet flow as an alternative hypothesis. Although both hypotheses can explain the recent slowdown, their respective forecasts of a long-term deceleration versus an acceleration of ice flow are contradictory. We present amplitude-versus-angle seismic data as the first observational test of the alternative hypothesis. We document transient modifications of basal sediment strengths by rapid subglacial drainages of supraglacial lakes, the primary current control on summer ice sheet flow according to our numerical model. Our observations agree with simulations of initial postdrainage sediment weakening and ice flow accelerations, and subsequent sediment restrengthening and ice flow decelerations, and thus confirm the alternative hypothesis. Although simulated melt season acceleration of ice flow due to weakening of subglacial sediments does not currently outweigh winter slowdown forced by self regulation, they could dominate over the longer term. Subglacial sediments beneath the Greenland Ice Sheet must therefore be mapped and characterized, and a sedimentary control of ice flow must be evaluated against competing self-regulation mechanisms. |
format |
Article in Journal/Newspaper |
author |
Kulessa, Bernd Hubbard, Alun L. Booth, Adam D. Bougamont, Marion Dow, Christine F. Doyle, Samuel H. Christoffersen, Poul Lindback, Katrin Pettersson, Rickard Fitzpatrick, Andrew A. W. Jones, Glenn A. |
author_facet |
Kulessa, Bernd Hubbard, Alun L. Booth, Adam D. Bougamont, Marion Dow, Christine F. Doyle, Samuel H. Christoffersen, Poul Lindback, Katrin Pettersson, Rickard Fitzpatrick, Andrew A. W. Jones, Glenn A. |
author_sort |
Kulessa, Bernd |
title |
Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow |
title_short |
Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow |
title_full |
Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow |
title_fullStr |
Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow |
title_full_unstemmed |
Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow |
title_sort |
seismic evidence for complex sedimentary control of greenland ice sheet flow |
publisher |
Uppsala universitet, Luft-, vatten- och landskapslära |
publishDate |
2017 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-336647 https://doi.org/10.1126/sciadv.1603071 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_relation |
Science Advances, 2017, 3:8, http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-336647 doi:10.1126/sciadv.1603071 ISI:000411589900043 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1126/sciadv.1603071 |
container_title |
Science Advances |
container_volume |
3 |
container_issue |
8 |
container_start_page |
e1603071 |
_version_ |
1766016273059151872 |