Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka
Understanding how marine-based ice streams operated during episodes of deglaciation requires geochronological data that constrain both timing of deglaciation and changes in their flow behaviour, such as that from unconstrained ice streaming to topographically restricted flow. We present seventeen ne...
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ftleedsuniv:oai:eprints.whiterose.ac.uk:118025 2023-05-15T16:38:12+02:00 Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka Small, D. Benetti, S. Dove, D. Ballantyne, C.K. Fabel, D. Clark, C.D. Gheorghiu, D.M. Newall, J. Xu, S. 2017-07 text https://eprints.whiterose.ac.uk/118025/ https://eprints.whiterose.ac.uk/118025/1/1-s2.0-S0277379117303499-main.pdf https://doi.org/10.1016/j.quascirev.2017.04.021 en eng Elsevier https://eprints.whiterose.ac.uk/118025/1/1-s2.0-S0277379117303499-main.pdf Small, D., Benetti, S., Dove, D. et al. (6 more authors) (2017) Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka. Quaternary Science Reviews, 167. C. pp. 30-46. ISSN 0277-3791 cc_by_4 CC-BY Article PeerReviewed 2017 ftleedsuniv https://doi.org/10.1016/j.quascirev.2017.04.021 2023-01-30T21:56:07Z Understanding how marine-based ice streams operated during episodes of deglaciation requires geochronological data that constrain both timing of deglaciation and changes in their flow behaviour, such as that from unconstrained ice streaming to topographically restricted flow. We present seventeen new 10Be exposure ages from glacial boulders and bedrock at sites in western Scotland within the area drained by the Hebrides Ice Stream, a marine-based ice stream that drained a large proportion of the former British-Irish Ice Sheet. Exposure ages from Tiree constrain deglaciation of a topographic high within the central zone of the ice stream, from which convergent flowsets were produced during ice streaming. These ages thus constrain thinning of the Hebrides Ice Stream, which, on the basis of supporting information, we infer to represent cessation of ice streaming at 20.6 ± 1.2 ka, 3–4 ka earlier than previously inferred. A period of more topographically restricted flow produced flow indicators superimposed on those relating to full ice stream conditions, and exposure ages from up-stream of these constrain deglaciation to 17.5 ± 1.0 ka. Complete deglaciation of the marine sector of the Hebrides Ice Stream occurred by 17–16 ka at which time the ice margin was located near the present coastline. Exposure ages from the southernmost Outer Hebrides (Mingulay and Barra) indicate deglaciation at 18.9 ± 1.0 and 17.1 ± 1.0 ka respectively, demonstrating that an independent ice cap persisted on the southern Outer Hebrides for 3–4 ka after initial ice stream deglaciation. This suggests that deglaciation of the Hebrides Ice Stream was focused along major submarine troughs. Collectively, our data constrain initial deglaciation and changes in flow regime of the Hebrides Ice Stream, final deglaciation of its marine sector, and deglaciation of the southern portion of the independent Outer Hebrides Ice Cap, providing chronological constraints on future numerical reconstructions of this key sector of the former British-Irish Ice Sheet. Article in Journal/Newspaper Ice cap Ice Sheet Ice Stream A White Rose Research Online (Universities of Leeds, Sheffield & York) Barra ENVELOPE(-61.417,-61.417,-64.367,-64.367) Quaternary Science Reviews 167 30 46 |
institution |
Open Polar |
collection |
White Rose Research Online (Universities of Leeds, Sheffield & York) |
op_collection_id |
ftleedsuniv |
language |
English |
description |
Understanding how marine-based ice streams operated during episodes of deglaciation requires geochronological data that constrain both timing of deglaciation and changes in their flow behaviour, such as that from unconstrained ice streaming to topographically restricted flow. We present seventeen new 10Be exposure ages from glacial boulders and bedrock at sites in western Scotland within the area drained by the Hebrides Ice Stream, a marine-based ice stream that drained a large proportion of the former British-Irish Ice Sheet. Exposure ages from Tiree constrain deglaciation of a topographic high within the central zone of the ice stream, from which convergent flowsets were produced during ice streaming. These ages thus constrain thinning of the Hebrides Ice Stream, which, on the basis of supporting information, we infer to represent cessation of ice streaming at 20.6 ± 1.2 ka, 3–4 ka earlier than previously inferred. A period of more topographically restricted flow produced flow indicators superimposed on those relating to full ice stream conditions, and exposure ages from up-stream of these constrain deglaciation to 17.5 ± 1.0 ka. Complete deglaciation of the marine sector of the Hebrides Ice Stream occurred by 17–16 ka at which time the ice margin was located near the present coastline. Exposure ages from the southernmost Outer Hebrides (Mingulay and Barra) indicate deglaciation at 18.9 ± 1.0 and 17.1 ± 1.0 ka respectively, demonstrating that an independent ice cap persisted on the southern Outer Hebrides for 3–4 ka after initial ice stream deglaciation. This suggests that deglaciation of the Hebrides Ice Stream was focused along major submarine troughs. Collectively, our data constrain initial deglaciation and changes in flow regime of the Hebrides Ice Stream, final deglaciation of its marine sector, and deglaciation of the southern portion of the independent Outer Hebrides Ice Cap, providing chronological constraints on future numerical reconstructions of this key sector of the former British-Irish Ice Sheet. |
format |
Article in Journal/Newspaper |
author |
Small, D. Benetti, S. Dove, D. Ballantyne, C.K. Fabel, D. Clark, C.D. Gheorghiu, D.M. Newall, J. Xu, S. |
spellingShingle |
Small, D. Benetti, S. Dove, D. Ballantyne, C.K. Fabel, D. Clark, C.D. Gheorghiu, D.M. Newall, J. Xu, S. Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka |
author_facet |
Small, D. Benetti, S. Dove, D. Ballantyne, C.K. Fabel, D. Clark, C.D. Gheorghiu, D.M. Newall, J. Xu, S. |
author_sort |
Small, D. |
title |
Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka |
title_short |
Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka |
title_full |
Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka |
title_fullStr |
Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka |
title_full_unstemmed |
Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka |
title_sort |
cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western scotland, 21–16 ka |
publisher |
Elsevier |
publishDate |
2017 |
url |
https://eprints.whiterose.ac.uk/118025/ https://eprints.whiterose.ac.uk/118025/1/1-s2.0-S0277379117303499-main.pdf https://doi.org/10.1016/j.quascirev.2017.04.021 |
long_lat |
ENVELOPE(-61.417,-61.417,-64.367,-64.367) |
geographic |
Barra |
geographic_facet |
Barra |
genre |
Ice cap Ice Sheet Ice Stream A |
genre_facet |
Ice cap Ice Sheet Ice Stream A |
op_relation |
https://eprints.whiterose.ac.uk/118025/1/1-s2.0-S0277379117303499-main.pdf Small, D., Benetti, S., Dove, D. et al. (6 more authors) (2017) Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka. Quaternary Science Reviews, 167. C. pp. 30-46. ISSN 0277-3791 |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.quascirev.2017.04.021 |
container_title |
Quaternary Science Reviews |
container_volume |
167 |
container_start_page |
30 |
op_container_end_page |
46 |
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1766028488791293952 |