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dc.contributor.authorKulessa, Bernd
dc.contributor.authorHubbard, Alun Lloyd
dc.contributor.authorBooth, Adam D.
dc.contributor.authorBougamont, Marion
dc.contributor.authorDow, Christine F.
dc.contributor.authorDoyle, Samuel H.
dc.contributor.authorChristoffersen, Poul
dc.contributor.authorLindbäck, Katrin
dc.contributor.authorPettersson, Rickard
dc.contributor.authorFitzpatrick, Andrew A.W.
dc.contributor.authorJones, Glenn A.
dc.date.accessioned2018-04-03T09:25:30Z
dc.date.available2018-04-03T09:25:30Z
dc.date.issued2017-08-16
dc.description.abstractThe 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 selfregulation, 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.en_US
dc.descriptionSource at: <a href=http://doi.org/10.1126/sciadv.1603071> http://doi.org/10.1126/sciadv.1603071 </a>en_US
dc.identifier.citationKulessa, B., Hubbard, A. L., Booth, A. D., Bougamont, M., Dow, C. F., Doyle, S. H., Christoffersen, P., ... Jones, G. A. (2017). Seismic evidence for complex sedimentary control of Greenland Ice Sheet flow. Science Advances, 3(8), 1-9. http://doi.org/10.1126/sciadv.1603071en_US
dc.identifier.cristinIDFRIDAID 1487549
dc.identifier.doi10.1126/sciadv.1603071
dc.identifier.issn2375-2548
dc.identifier.urihttps://hdl.handle.net/10037/12459
dc.language.isoengen_US
dc.publisherAmerican Association for the Advancement of Science: Science Advancesen_US
dc.relation.journalScience Advances
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/en_US
dc.rights.accessRightsopenAccessen_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Kvartærgeologi, glasiologi: 465en_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450::Quaternary geology, glaciology: 465en_US
dc.titleSeismic evidence for complex sedimentary control of Greenland Ice Sheet flowen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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