posted on 2023-05-18, 10:40authored byBradley, SL, Hindmarsh, RCA, Whitehouse, PL, Bentley, MJ, Matt KingMatt King
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.
Funding
Australian Research Council
History
Publication title
Earth and Planetary Science Letters
Volume
413
Pagination
79-89
ISSN
0012-821X
Department/School
School of Geography, Planning and Spatial Sciences
Publisher
Elsevier Science Bv
Place of publication
Po Box 211, Amsterdam, Netherlands, 1000 Ae
Rights statement
Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) https://creativecommons.org/licenses/by-nc-nd/4.0/