Towards modelling of corrugation ridges at ice-sheet grounding lines

Hogan, Kelly A., Warburton, Katarzyna L. P., Graham, Alastair G. C., Neufeld, Jerome A., Hewitt, Duncan R., Dowdeswell, Julian A. and Larter, Robert D. 2023. Towards modelling of corrugation ridges at ice-sheet grounding lines. The Cryosphere 17 (7) , 2645–2664. 10.5194/tc-17-2645-2023

PDF - Published Version Available under License Creative Commons Attribution. Download (6MB)

Abstract

Improvements in the resolution of sea-floor mapping techniques have revealed extremely regular, sub-metre-scale ridge landforms produced by the tidal flexure of ice-shelf grounding lines as they retreated very rapidly (i.e. at rates of several kilometres per year). Guided by such novel sea-floor observations from Thwaites Glacier, West Antarctica, we present three mathematical models for the formation of these corrugation ridges at a tidally migrating grounding line (that is retreating at a constant rate), where each ridge is formed by either constant till flux to the grounding line, till extrusion from the grounding line, or the resuspension and transport of grains from the grounding-zone bed. We find that both till extrusion (squeezing out till like toothpaste as the ice sheet re-settles on the sea floor) and resuspension and transport of material can qualitatively reproduce regular, delicate ridges at a retreating grounding line, as described by sea-floor observations. By considering the known properties of subglacial sediments, we agree with existing schematic models that the most likely mechanism for ridge formation is till extrusion at each low-tide position, essentially preserving an imprint of the ice-sheet grounding line as it retreated. However, when realistic (shallow) bed slopes are used in the simulations, ridges start to overprint one another, suggesting that, to preserve the regular ridges that have been observed, grounding line retreat rates (driven by dynamic thinning?) may be even higher than previously thought.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Publisher:	Copernicus Publications
ISSN:	1994-0424
Funders:	NERC
Date of First Compliant Deposit:	19 February 2024
Date of Acceptance:	21 April 2023
Last Modified:	19 Feb 2024 10:15
URI:	https://orca.cardiff.ac.uk/id/eprint/165943

Actions (repository staff only)

Edit Item