Ice-stream demise dynamically conditioned by trough shape and bed strength

Bradwell, T. et al. (2019) Ice-stream demise dynamically conditioned by trough shape and bed strength. Science Advances, 5(4), eaau1380. (doi: 10.1126/sciadv.aau1380) (PMID:31058217) (PMCID:PMC6498188)

Abstract

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.

• Item Type: Articles
• Additional Information: This research wassupported by a NERC UK consortium grant (BRITICE-CHRONO NE/J008672/1).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fabel, Dr Derek
• Authors: Bradwell, T., Small, D., Fabel, D., Smedley, R. K., Clark, C. D., Saher, M. H., Callard, S. L., Chiverrell, R. C., Dove, D., Moreton, S. G., Roberts, D. H., Duller, G. A.T., and Ó Cofaigh, C.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Science Advances
• Publisher: American Association for the Advancement of Science
• ISSN: 2375-2548
• ISSN (Online): 2375-2548
• Copyright Holders: Copyright © 2019 The Authors
• First Published: First published in Science Advances 5(4):eaau1380
• Publisher Policy: Reproduced under a Creative Commons License