Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland
The research reported here was supported by UK NERC grant NER/B/S/2001/0919 Trimlines separating glacially abraded lower slopes from blockfield-covered summits on Irish mountains have traditionally been interpreted as representing the upper limit of the last ice sheet during the Last Glacial Maximum...
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ftstandrewserep:oai:research-repository.st-andrews.ac.uk:10023/6021 2023-07-02T03:32:36+02:00 Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland Ballantyne, Colin Stone, John O. University of St Andrews. Geography & Sustainable Development 2015-01-19T14:31:04Z 11 application/pdf http://hdl.handle.net/10023/6021 https://doi.org/10.1111/bor.12109 eng eng Boreas Ballantyne , C & Stone , J O 2015 , ' Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland ' , Boreas , vol. 44 , no. 2 , pp. 277-287 . https://doi.org/10.1111/bor.12109 0300-9483 PURE: 162210320 PURE UUID: 51b1a5f9-a888-42b2-84db-a2a036e9d1df Scopus: 84925643193 WOS: 000351852200002 http://hdl.handle.net/10023/6021 https://doi.org/10.1111/bor.12109 © 2015. The Authors. Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. G Geography (General) QE Geology NDAS G1 QE Journal article 2015 ftstandrewserep https://doi.org/10.1111/bor.12109 2023-06-13T18:29:05Z The research reported here was supported by UK NERC grant NER/B/S/2001/0919 Trimlines separating glacially abraded lower slopes from blockfield-covered summits on Irish mountains have traditionally been interpreted as representing the upper limit of the last ice sheet during the Last Glacial Maximum (LGM). Cosmogenic 10Be exposure ages obtained for samples from glacially deposited perched boulders resting on blockfield debris on the summit area of Slievenamon (721 m a.s.l.) in southern Ireland demonstrate emplacement by the last Irish Ice Sheet (IIS), implying preservation of the blockfield under cold-based ice during the LGM, and supporting the view that trimlines throughout the British Isles represent former englacial thermal regime boundaries between a lower zone of warm-based sliding ice and an upper zone of cold-based ice. The youngest exposure age (22.6±1.1 or 21.0±0.9 ka, depending on the 10Be production rate employed) is statistically indistinguishable from the mean age (23.4±1.2 or 21.8±0.9 ka) obtained for two samples from ice-abraded bedrock at high ground on Blackstairs Mountain, 51 km to the east, and with published cosmogenic 36Cl ages. Collectively, these ages imply (i) early (24–21 ka) thinning of the last IIS and emergence of high ground in SE Ireland; (ii) relatively brief (1–3 ka) glacial occupation of southernmost Ireland during the LGM; (iii) decoupling of the Irish Sea Ice Stream and ice from the Irish midlands within a similar time frame; and (iv) that the southern fringe of Ireland was deglaciated before western and northern Ireland. Publisher PDF Peer reviewed Article in Journal/Newspaper Ice Sheet Sea ice University of St Andrews: Digital Research Repository Ner ENVELOPE(6.622,6.622,62.612,62.612) Boreas 44 2 277 287 |
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Open Polar |
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University of St Andrews: Digital Research Repository |
op_collection_id |
ftstandrewserep |
language |
English |
topic |
G Geography (General) QE Geology NDAS G1 QE |
spellingShingle |
G Geography (General) QE Geology NDAS G1 QE Ballantyne, Colin Stone, John O. Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland |
topic_facet |
G Geography (General) QE Geology NDAS G1 QE |
description |
The research reported here was supported by UK NERC grant NER/B/S/2001/0919 Trimlines separating glacially abraded lower slopes from blockfield-covered summits on Irish mountains have traditionally been interpreted as representing the upper limit of the last ice sheet during the Last Glacial Maximum (LGM). Cosmogenic 10Be exposure ages obtained for samples from glacially deposited perched boulders resting on blockfield debris on the summit area of Slievenamon (721 m a.s.l.) in southern Ireland demonstrate emplacement by the last Irish Ice Sheet (IIS), implying preservation of the blockfield under cold-based ice during the LGM, and supporting the view that trimlines throughout the British Isles represent former englacial thermal regime boundaries between a lower zone of warm-based sliding ice and an upper zone of cold-based ice. The youngest exposure age (22.6±1.1 or 21.0±0.9 ka, depending on the 10Be production rate employed) is statistically indistinguishable from the mean age (23.4±1.2 or 21.8±0.9 ka) obtained for two samples from ice-abraded bedrock at high ground on Blackstairs Mountain, 51 km to the east, and with published cosmogenic 36Cl ages. Collectively, these ages imply (i) early (24–21 ka) thinning of the last IIS and emergence of high ground in SE Ireland; (ii) relatively brief (1–3 ka) glacial occupation of southernmost Ireland during the LGM; (iii) decoupling of the Irish Sea Ice Stream and ice from the Irish midlands within a similar time frame; and (iv) that the southern fringe of Ireland was deglaciated before western and northern Ireland. Publisher PDF Peer reviewed |
author2 |
University of St Andrews. Geography & Sustainable Development |
format |
Article in Journal/Newspaper |
author |
Ballantyne, Colin Stone, John O. |
author_facet |
Ballantyne, Colin Stone, John O. |
author_sort |
Ballantyne, Colin |
title |
Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland |
title_short |
Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland |
title_full |
Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland |
title_fullStr |
Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland |
title_full_unstemmed |
Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland |
title_sort |
trimlines, blockfields and the vertical extent of the last ice sheet in southern ireland |
publishDate |
2015 |
url |
http://hdl.handle.net/10023/6021 https://doi.org/10.1111/bor.12109 |
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ENVELOPE(6.622,6.622,62.612,62.612) |
geographic |
Ner |
geographic_facet |
Ner |
genre |
Ice Sheet Sea ice |
genre_facet |
Ice Sheet Sea ice |
op_relation |
Boreas Ballantyne , C & Stone , J O 2015 , ' Trimlines, blockfields and the vertical extent of the last ice sheet in southern Ireland ' , Boreas , vol. 44 , no. 2 , pp. 277-287 . https://doi.org/10.1111/bor.12109 0300-9483 PURE: 162210320 PURE UUID: 51b1a5f9-a888-42b2-84db-a2a036e9d1df Scopus: 84925643193 WOS: 000351852200002 http://hdl.handle.net/10023/6021 https://doi.org/10.1111/bor.12109 |
op_rights |
© 2015. The Authors. Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
op_doi |
https://doi.org/10.1111/bor.12109 |
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287 |
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