Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams

<p>Ice streams are corridors of fast-flowing ice that control mass transfers from continental ice sheets to oceans. Their flow speeds are known to accelerate and decelerate, their activity can switch on and off, and even their locations can shift entirely. Our analogue physical experiments...

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Main Authors: T. Lelandais, É. Ravier, S. Pochat, O. Bourgeois, C. Clark, R. Mourgues, P. Strzerzynski
Format: Article
Language:English
Published: Copernicus Publications 2018-08-01
Series:The Cryosphere
Online Access:https://www.the-cryosphere.net/12/2759/2018/tc-12-2759-2018.pdf
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author T. Lelandais
É. Ravier
S. Pochat
O. Bourgeois
C. Clark
R. Mourgues
P. Strzerzynski
author_facet T. Lelandais
É. Ravier
S. Pochat
O. Bourgeois
C. Clark
R. Mourgues
P. Strzerzynski
author_sort T. Lelandais
collection DOAJ
description <p>Ice streams are corridors of fast-flowing ice that control mass transfers from continental ice sheets to oceans. Their flow speeds are known to accelerate and decelerate, their activity can switch on and off, and even their locations can shift entirely. Our analogue physical experiments reveal that a life cycle incorporating evolving subglacial meltwater routing and bed erosion can govern this complex transitory behaviour. The modelled ice streams switch on and accelerate when subglacial water pockets drain as marginal outburst floods (basal decoupling). Then they decelerate when the lubricating water drainage system spontaneously organizes itself into channels that create tunnel valleys (partial basal recoupling). The ice streams surge or jump in location when these water drainage systems maintain low discharge but they ultimately switch off when tunnel valleys have expanded to develop efficient drainage systems. Beyond reconciling previously disconnected observations of modern and ancient ice streams into a single life cycle, the modelling suggests that tunnel valley development may be crucial in stabilizing portions of ice sheets during periods of climate change.</p>
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spelling doaj.art-80cce5937f1347daaeef3c111235782a2022-12-21T20:01:52ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242018-08-01122759277210.5194/tc-12-2759-2018Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streamsT. Lelandais0É. Ravier1S. Pochat2O. Bourgeois3C. Clark4R. Mourgues5P. Strzerzynski6Laboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans CEDEX 9, FranceLaboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans CEDEX 9, FranceLaboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322 Nantes CEDEX 3, FranceLaboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322 Nantes CEDEX 3, FranceDepartment of Geography, University of Sheffield, Sheffield, UKLaboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans CEDEX 9, FranceLaboratoire de Planétologie et Géodynamique, UMR 6112, CNRS, Le Mans Université, Avenue Olivier Messiaen, 72085 Le Mans CEDEX 9, France<p>Ice streams are corridors of fast-flowing ice that control mass transfers from continental ice sheets to oceans. Their flow speeds are known to accelerate and decelerate, their activity can switch on and off, and even their locations can shift entirely. Our analogue physical experiments reveal that a life cycle incorporating evolving subglacial meltwater routing and bed erosion can govern this complex transitory behaviour. The modelled ice streams switch on and accelerate when subglacial water pockets drain as marginal outburst floods (basal decoupling). Then they decelerate when the lubricating water drainage system spontaneously organizes itself into channels that create tunnel valleys (partial basal recoupling). The ice streams surge or jump in location when these water drainage systems maintain low discharge but they ultimately switch off when tunnel valleys have expanded to develop efficient drainage systems. Beyond reconciling previously disconnected observations of modern and ancient ice streams into a single life cycle, the modelling suggests that tunnel valley development may be crucial in stabilizing portions of ice sheets during periods of climate change.</p>https://www.the-cryosphere.net/12/2759/2018/tc-12-2759-2018.pdf
spellingShingle T. Lelandais
É. Ravier
S. Pochat
O. Bourgeois
C. Clark
R. Mourgues
P. Strzerzynski
Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams
The Cryosphere
title Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams
title_full Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams
title_fullStr Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams
title_full_unstemmed Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams
title_short Modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams
title_sort modelled subglacial floods and tunnel valleys control the life cycle of transitory ice streams
url https://www.the-cryosphere.net/12/2759/2018/tc-12-2759-2018.pdf
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