Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks
Marine ice-cliff instability (MICI) processes could accelerate future retreat of the Antarctic Ice Sheet if ice shelves that buttress grounding lines more than 800 metres below sea level are lost1, 2. The present-day grounding zones of the Pine Island and Thwaites glaciers in West Antarctica need to...
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ftnerc:oai:nora.nerc.ac.uk:514800 2023-05-15T13:49:33+02:00 Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks Wise, Matthew G. Dowdeswell, Julian A. Jakobsson, Martin Larter, Robert D. 2017-10-26 text http://nora.nerc.ac.uk/id/eprint/514800/ https://nora.nerc.ac.uk/id/eprint/514800/1/Nature_final_accepted_ms.pdf https://www.nature.com/nature/journal/v550/n7677/full/nature24458.html en eng Nature Publishing Group https://nora.nerc.ac.uk/id/eprint/514800/1/Nature_final_accepted_ms.pdf Wise, Matthew G.; Dowdeswell, Julian A.; Jakobsson, Martin; Larter, Robert D. orcid:0000-0002-8414-7389 . 2017 Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks. Nature, 550. 506-510. https://doi.org/10.1038/nature24458 <https://doi.org/10.1038/nature24458> Publication - Article PeerReviewed 2017 ftnerc https://doi.org/10.1038/nature24458 2023-02-04T19:43:44Z Marine ice-cliff instability (MICI) processes could accelerate future retreat of the Antarctic Ice Sheet if ice shelves that buttress grounding lines more than 800 metres below sea level are lost1, 2. The present-day grounding zones of the Pine Island and Thwaites glaciers in West Antarctica need to retreat only short distances before they reach extensive retrograde slopes3, 4. When grounding zones of glaciers retreat onto such slopes, theoretical considerations and modelling results indicate that the retreat becomes unstable (marine ice-sheet instability) and thus accelerates5. It is thought1, 2 that MICI is triggered when this retreat produces ice cliffs above the water line with heights approaching about 90 metres. However, observational evidence confirming the action of MICI has not previously been reported. Here we present observational evidence that rapid deglacial ice-sheet retreat into Pine Island Bay proceeded in a similar manner to that simulated in a recent modelling study1, driven by MICI. Iceberg-keel plough marks on the sea-floor provide geological evidence of past and present iceberg morphology, keel depth6 and drift direction7. From the planform shape and cross-sectional morphologies of iceberg-keel plough marks, we find that iceberg calving during the most recent deglaciation was not characterized by small numbers of large, tabular icebergs as is observed today8, 9, which would produce wide, flat-based plough marks10 or toothcomb-like multi-keeled plough marks11, 12. Instead, it was characterized by large numbers of smaller icebergs with V-shaped keels. Geological evidence of the form and water-depth distribution of the plough marks indicates calving-margin thicknesses equivalent to the threshold that is predicted to trigger ice-cliff structural collapse as a result of MICI13. We infer rapid and sustained ice-sheet retreat driven by MICI, commencing around 12,300 years ago and terminating before about 11,200 years ago, which produced large numbers of icebergs smaller than the typical tabular ... Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Ice Shelves Iceberg* Pine Island Pine Island Bay West Antarctica Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic West Antarctica Island Bay ENVELOPE(-109.085,-109.085,59.534,59.534) Pine Island Bay ENVELOPE(-102.000,-102.000,-74.750,-74.750) Buttress ENVELOPE(-57.083,-57.083,-63.550,-63.550) Nature 550 7677 506 510 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
language |
English |
description |
Marine ice-cliff instability (MICI) processes could accelerate future retreat of the Antarctic Ice Sheet if ice shelves that buttress grounding lines more than 800 metres below sea level are lost1, 2. The present-day grounding zones of the Pine Island and Thwaites glaciers in West Antarctica need to retreat only short distances before they reach extensive retrograde slopes3, 4. When grounding zones of glaciers retreat onto such slopes, theoretical considerations and modelling results indicate that the retreat becomes unstable (marine ice-sheet instability) and thus accelerates5. It is thought1, 2 that MICI is triggered when this retreat produces ice cliffs above the water line with heights approaching about 90 metres. However, observational evidence confirming the action of MICI has not previously been reported. Here we present observational evidence that rapid deglacial ice-sheet retreat into Pine Island Bay proceeded in a similar manner to that simulated in a recent modelling study1, driven by MICI. Iceberg-keel plough marks on the sea-floor provide geological evidence of past and present iceberg morphology, keel depth6 and drift direction7. From the planform shape and cross-sectional morphologies of iceberg-keel plough marks, we find that iceberg calving during the most recent deglaciation was not characterized by small numbers of large, tabular icebergs as is observed today8, 9, which would produce wide, flat-based plough marks10 or toothcomb-like multi-keeled plough marks11, 12. Instead, it was characterized by large numbers of smaller icebergs with V-shaped keels. Geological evidence of the form and water-depth distribution of the plough marks indicates calving-margin thicknesses equivalent to the threshold that is predicted to trigger ice-cliff structural collapse as a result of MICI13. We infer rapid and sustained ice-sheet retreat driven by MICI, commencing around 12,300 years ago and terminating before about 11,200 years ago, which produced large numbers of icebergs smaller than the typical tabular ... |
format |
Article in Journal/Newspaper |
author |
Wise, Matthew G. Dowdeswell, Julian A. Jakobsson, Martin Larter, Robert D. |
spellingShingle |
Wise, Matthew G. Dowdeswell, Julian A. Jakobsson, Martin Larter, Robert D. Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks |
author_facet |
Wise, Matthew G. Dowdeswell, Julian A. Jakobsson, Martin Larter, Robert D. |
author_sort |
Wise, Matthew G. |
title |
Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks |
title_short |
Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks |
title_full |
Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks |
title_fullStr |
Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks |
title_full_unstemmed |
Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks |
title_sort |
evidence of marine ice-cliff instability in pine island bay from iceberg-keel plough marks |
publisher |
Nature Publishing Group |
publishDate |
2017 |
url |
http://nora.nerc.ac.uk/id/eprint/514800/ https://nora.nerc.ac.uk/id/eprint/514800/1/Nature_final_accepted_ms.pdf https://www.nature.com/nature/journal/v550/n7677/full/nature24458.html |
long_lat |
ENVELOPE(-109.085,-109.085,59.534,59.534) ENVELOPE(-102.000,-102.000,-74.750,-74.750) ENVELOPE(-57.083,-57.083,-63.550,-63.550) |
geographic |
Antarctic The Antarctic West Antarctica Island Bay Pine Island Bay Buttress |
geographic_facet |
Antarctic The Antarctic West Antarctica Island Bay Pine Island Bay Buttress |
genre |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelves Iceberg* Pine Island Pine Island Bay West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Ice Shelves Iceberg* Pine Island Pine Island Bay West Antarctica |
op_relation |
https://nora.nerc.ac.uk/id/eprint/514800/1/Nature_final_accepted_ms.pdf Wise, Matthew G.; Dowdeswell, Julian A.; Jakobsson, Martin; Larter, Robert D. orcid:0000-0002-8414-7389 . 2017 Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks. Nature, 550. 506-510. https://doi.org/10.1038/nature24458 <https://doi.org/10.1038/nature24458> |
op_doi |
https://doi.org/10.1038/nature24458 |
container_title |
Nature |
container_volume |
550 |
container_issue |
7677 |
container_start_page |
506 |
op_container_end_page |
510 |
_version_ |
1766251570626822144 |