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dc.contributor.authorPatton, Henry
dc.contributor.authorSwift, D.A.
dc.contributor.authorClark, C.D.
dc.contributor.authorLivingstone, Stephen J.
dc.contributor.authorCook, S.J.
dc.date.accessioned2017-03-09T13:48:25Z
dc.date.available2017-03-09T13:48:25Z
dc.date.issued2016-09-15
dc.description.abstractGlacier bed overdeepenings are ubiquitous in glacier systems and likely exert significant influence on ice dynamics, subglacial hydrology, and ice stability. Understanding of overdeepening formation and evolution has been hampered by an absence of quantitative empirical studies of their distribution and morphology, with process insights having been drawn largely from theoretical or numerical studies. To address this shortcoming, we first map the distribution of potential overdeepenings beneath the Antarctic and Greenland ice sheets using a GIS-based algorithm that identifies closed-contours in the bed topography and then describe and analyse the characteristics and metrics of a subset of overdeepenings that pass further quality control criteria. Overdeepenings are found to be widespread, but are particularly associated with areas of topographically laterally constrained ice flow, notably near the ice sheet margins where outlet systems follow deeply incised troughs. Overdeepenings also occur in regions of topographically unconstrained ice flow (for example, beneath the Siple Coast ice streams and on the Greenland continental shelf). Metrics indicate that overdeepening growth is generally allometric and that topographic confinement of ice flow in general enhances overdeepening depth. However, overdeepening depth is skewed towards shallow values – typically 200–300 m – indicating that the rate of deepening slows with overdeepening age. This is reflected in a decline in adverse slope steepness with increasing overdeepening planform size. Finally, overdeepening long-profiles are found to support headward quarrying as the primary factor in overdeepening development. These observations support proposed negative feedbacks related to hydrology and sediment transport that stabilise overdeepening growth through sedimentation on the adverse slope but permit continued overdeepening planform enlargement by processes of headward erosion.en_US
dc.description.sponsorshipDAS thanks the National Cooperative for the Disposal of Radioactive Waste (Nagra), Switzerland, for their role in stimulating new research on the topic of focused glacial erosion, and DAS and HP further thank Nagra for funding the quantitative study of overdeepening morphology on which this paper is based (grant 11’716 Fcu/bys). HP also acknowledges support by the Research Council of Norway through its Centres of Excellence funding scheme (grant 223259) and the PetroMaks project “Glaciations in the Barents Sea area (GlaciBar)” (grant 200672). Jen_US
dc.descriptionPublished version at <a href=http://doi.org/10.1016/j.quascirev.2016.07.012>http://doi.org/10.1016/j.quascirev.2016.07.012</a>. License <a href=http://creativecommons.org/licenses/by-nc-nd/4.0/>CC BY-NC-ND 4.0</a>.en_US
dc.identifier.citationPatton H, Swift, Clark C, Livingstone SJ, Cook. Distribution and characteristics of overdeepenings beneath the Greenland and Antarctic ice sheets: Implications for overdeepening origin and evolution. Quaternary Science Reviews. 2016;148:128-145en_US
dc.identifier.issn0277-3791
dc.identifier.issn1873-457X
dc.identifier.otherFRIDAID 1369102
dc.identifier.other10.1016/j.quascirev.2016.07.012
dc.identifier.urihttp://hdl.handle.net/10037/10521
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalQuaternary Science Reviews
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN//200672/Norway/PetroMaks/GlaciBar/en_US
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN//223259/Norway///en_US
dc.rights.accessRightsopenAccessen_US
dc.subjectGlacial erosionen_US
dc.subjectLandscape evolutionen_US
dc.subjectOverdeepeningen_US
dc.subjectGeomorphologyen_US
dc.subjectIce sheeten_US
dc.subjectVDP::Mathematics and natural science: 400::Geosciences: 450en_US
dc.titleDistribution and characteristics of overdeepenings beneath the Greenland and Antarctic ice sheets: Implications for overdeepening origin and evolutionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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