Towards modelling of corrugation ridges at ice-sheet grounding lines
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 obs...
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2023
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ftucl:oai:eprints.ucl.ac.uk.OAI2:10174763 2023-12-24T10:11:29+01:00 Towards modelling of corrugation ridges at ice-sheet grounding lines Hogan, Kelly A Warburton, Katarzyna LP Graham, Alastair GC Neufeld, Jerome A Hewitt, Duncan R Dowdeswell, Julian A Larter, Robert D 2023-07-11 text https://discovery.ucl.ac.uk/id/eprint/10174763/1/tc-17-2645-2023.pdf https://discovery.ucl.ac.uk/id/eprint/10174763/ eng eng COPERNICUS GESELLSCHAFT MBH https://discovery.ucl.ac.uk/id/eprint/10174763/1/tc-17-2645-2023.pdf https://discovery.ucl.ac.uk/id/eprint/10174763/ open The Cryosphere , 17 (7) pp. 2645-2664. (2023) Article 2023 ftucl 2023-11-27T13:07:38Z 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. Article in Journal/Newspaper Antarc* Antarctica Ice Sheet Ice Shelf The Cryosphere Thwaites Glacier West Antarctica University College London: UCL Discovery West Antarctica Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
description |
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. |
format |
Article in Journal/Newspaper |
author |
Hogan, Kelly A Warburton, Katarzyna LP Graham, Alastair GC Neufeld, Jerome A Hewitt, Duncan R Dowdeswell, Julian A Larter, Robert D |
spellingShingle |
Hogan, Kelly A Warburton, Katarzyna LP Graham, Alastair GC Neufeld, Jerome A Hewitt, Duncan R Dowdeswell, Julian A Larter, Robert D Towards modelling of corrugation ridges at ice-sheet grounding lines |
author_facet |
Hogan, Kelly A Warburton, Katarzyna LP Graham, Alastair GC Neufeld, Jerome A Hewitt, Duncan R Dowdeswell, Julian A Larter, Robert D |
author_sort |
Hogan, Kelly A |
title |
Towards modelling of corrugation ridges at ice-sheet grounding lines |
title_short |
Towards modelling of corrugation ridges at ice-sheet grounding lines |
title_full |
Towards modelling of corrugation ridges at ice-sheet grounding lines |
title_fullStr |
Towards modelling of corrugation ridges at ice-sheet grounding lines |
title_full_unstemmed |
Towards modelling of corrugation ridges at ice-sheet grounding lines |
title_sort |
towards modelling of corrugation ridges at ice-sheet grounding lines |
publisher |
COPERNICUS GESELLSCHAFT MBH |
publishDate |
2023 |
url |
https://discovery.ucl.ac.uk/id/eprint/10174763/1/tc-17-2645-2023.pdf https://discovery.ucl.ac.uk/id/eprint/10174763/ |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
West Antarctica Thwaites Glacier |
geographic_facet |
West Antarctica Thwaites Glacier |
genre |
Antarc* Antarctica Ice Sheet Ice Shelf The Cryosphere Thwaites Glacier West Antarctica |
genre_facet |
Antarc* Antarctica Ice Sheet Ice Shelf The Cryosphere Thwaites Glacier West Antarctica |
op_source |
The Cryosphere , 17 (7) pp. 2645-2664. (2023) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/10174763/1/tc-17-2645-2023.pdf https://discovery.ucl.ac.uk/id/eprint/10174763/ |
op_rights |
open |
_version_ |
1786165738885611520 |