Rapid Holocene thinning of an East Antarctic outlet glacier driven by marine ice sheet instability

Jones, R.S.; Mackintosh, A.N.; Norton, K.P.; Golledge, N.R.; Fogwill, C.J.; Kubik, P.W.; Christl, M.; Greenwood, S.L.

Abstract

Outlet glaciers grounded on a bed that deepens inland and extends below sea level are potentially vulnerable to ‘marine ice sheet instability’. This instability, which may lead to runaway ice loss, has been simulated in models, but its consequences have not been directly observed in geological records. Here we provide new surface-exposure ages from an outlet of the East Antarctic Ice Sheet that reveal rapid glacier thinning occurred approximately 7,000 years ago, in the absence of large environmental changes. Glacier thinning persisted for more than two and a half centuries, resulting in hundreds of metres of ice loss. Numerical simulations indicate that ice surface drawdown accelerated when the otherwise steadily retreating glacier encountered a bedrock trough. Together, the geological reconstruction and numerical simulations suggest that centennial-scale glacier thinning arose from unstable grounding line retreat. Capturing these instability processes in ice sheet models is important for predicting Antarctica’s future contribution to sea level change.

Citation

Jones, R., Mackintosh, A., Norton, K., Golledge, N., Fogwill, C., Kubik, P., …Greenwood, S. (2015). Rapid Holocene thinning of an East Antarctic outlet glacier driven by marine ice sheet instability. Nature Communications, 6, Article 8910. https://doi.org/10.1038/ncomms9910

• Journal Article Type: Article
• Acceptance Date: Oct 15, 2015
• Online Publication Date: Nov 26, 2015
• Publication Date: Nov 26, 2015
• Deposit Date: Nov 4, 2016
• Publicly Available Date: Nov 10, 2016
• Journal: Nature Communications
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 6
• Article Number: 8910
• DOI: https://doi.org/10.1038/ncomms9910
• Public URL: https://durham-repository.worktribe.com/output/1372960