Low post-glacial rebound rates in the Weddell Sea due to Late Holocene ice- sheet readvance

Bradley, S.L.; Hindmarsh, R.C.A.; Whitehouse, P.L.; Bentley, M.J.; King, M.A.

Abstract

Many ice-sheet reconstructions assume monotonic Holocene retreat for the West Antarctic Ice Sheet, but an increasing number of glaciological observations infer that some portions of the ice sheet may be readvancing, following retreat behind the present-day margin. A readvance in the Weddell Sea region can reconcile two outstanding problems: (i) the present-day widespread occurrence of seemingly stable ice streams grounded on beds that deepen inland; and (ii) the inability of models of glacial isostatic adjustment to match present-day uplift rates. By combining a suite of ice loading histories that include a readvance with a model of glacial isostatic adjustment we report substantial improvements to predictions of present-day uplift rates, including reconciling one problematic observation of land sinking. We suggest retreat behind present grounding lines occurred when the bed was lower, and isostatic recovery has since led to shallowing, ice sheet re-grounding and readvance. The paradoxical existence of grounding lines in apparently unstable configurations on reverse bed slopes may be resolved by invoking the process of unstable advance, in accordance with our load modelling.

Citation

Bradley, S., Hindmarsh, R., Whitehouse, P., Bentley, M., & King, M. (2015). Low post-glacial rebound rates in the Weddell Sea due to Late Holocene ice- sheet readvance. Earth and Planetary Science Letters, 413, 79-89. https://doi.org/10.1016/j.epsl.2014.12.039

• Journal Article Type: Article
• Acceptance Date: Dec 17, 2014
• Online Publication Date: Jan 16, 2015
• Publication Date: Mar 1, 2015
• Deposit Date: Dec 17, 2014
• Publicly Available Date: Jan 15, 2015
• Journal: Earth and Planetary Science Letters
• Print ISSN: 0012-821X
• Electronic ISSN: 1385-013X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 413
• Pages: 79-89
• DOI: https://doi.org/10.1016/j.epsl.2014.12.039
• Keywords: Grounding line stability, Antarctic Ice sheet, Glacial isostatic adjustment, Uplift rate, Weddell Sea, Deglaciation.
• Public URL: https://durham-repository.worktribe.com/output/1447989