Ice-stream demise dynamically conditioned by trough shape and bed strength
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In: Science Advances, Vol. 5, No. 4, eaau1380, 24.04.2019, p. eaau1380.
Research output: Contribution to journal › Article › peer-review
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T1 - Ice-stream demise dynamically conditioned by trough shape and bed strength
AU - Bradwell, Tom
AU - Small, David
AU - Fabel, Derek
AU - Smedley, Rachel
AU - Clark, Chris
AU - Saher, Margot
AU - Callard, Louise
AU - Chiverrell, Richard
AU - Dove, Dayton
AU - Moreton, Steven
AU - Roberts, David
AU - Duller, Geoff
AU - O'Cofaigh, Colm
PY - 2019/4/24
Y1 - 2019/4/24
N2 - Ice sheet mass loss is currently dominated by fast-flowing glaciers (ice streams) terminating in the ocean as ice shelves and resting on beds below sea level. The factors controlling ice-stream flow and retreat over longer time scales (>100 years), especially the role of three-dimensional bed shape and bed strength, remain major uncertainties. We focus on a former ice stream where trough shape and bed substrate are known, or can be defined, to reconstruct ice-stream retreat history and grounding-line movements over 15 millennia since the Last Glacial Maximum. We identify a major behavioral step change around 18,500 to 16,000 years ago—out of tune with external forcing factors—associated with the collapse of floating ice sectors and rapid ice-front retreat. We attribute this step change to a marked geological transition from a soft/weak bed to a hard/strong bed coincident with a change in trough geometry. Both these factors conditioned and ultimately hastened ice-stream demise.
AB - Ice sheet mass loss is currently dominated by fast-flowing glaciers (ice streams) terminating in the ocean as ice shelves and resting on beds below sea level. The factors controlling ice-stream flow and retreat over longer time scales (>100 years), especially the role of three-dimensional bed shape and bed strength, remain major uncertainties. We focus on a former ice stream where trough shape and bed substrate are known, or can be defined, to reconstruct ice-stream retreat history and grounding-line movements over 15 millennia since the Last Glacial Maximum. We identify a major behavioral step change around 18,500 to 16,000 years ago—out of tune with external forcing factors—associated with the collapse of floating ice sectors and rapid ice-front retreat. We attribute this step change to a marked geological transition from a soft/weak bed to a hard/strong bed coincident with a change in trough geometry. Both these factors conditioned and ultimately hastened ice-stream demise.
U2 - 10.1126/sciadv.aau1380
DO - 10.1126/sciadv.aau1380
M3 - Article
VL - 5
SP - eaau1380
JO - Science Advances
JF - Science Advances
SN - 2375-2548
IS - 4
M1 - eaau1380
ER -