Sedimentological signatures of the sub-Amery Ice Shelf circulation
Abstract Two sediment cores collected from beneath the Amery Ice Shelf, East Antarctica describe the physical sedimentation patterns beneath an existing major embayed ice shelf. Core AM01b was collected from a site of basal freezing, contrasting with core AM02, collected from a site of basal melting...
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Cambridge University Press (CUP)
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Online Access: | http://dx.doi.org/10.1017/s0954102007000697 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102007000697 |
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crcambridgeupr:10.1017/s0954102007000697 2024-09-15T17:38:41+00:00 Sedimentological signatures of the sub-Amery Ice Shelf circulation Hemer, M.A. Post, A.L. O'Brien, P.E. Craven, M. Truswell, E.M. Roberts, D. Harris, P.T. 2007 http://dx.doi.org/10.1017/s0954102007000697 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102007000697 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Antarctic Science volume 19, issue 4, page 497-506 ISSN 0954-1020 1365-2079 journal-article 2007 crcambridgeupr https://doi.org/10.1017/s0954102007000697 2024-07-31T04:04:04Z Abstract Two sediment cores collected from beneath the Amery Ice Shelf, East Antarctica describe the physical sedimentation patterns beneath an existing major embayed ice shelf. Core AM01b was collected from a site of basal freezing, contrasting with core AM02, collected from a site of basal melting. Both cores comprise Holocene siliceous muddy ooze (SMO), however, AM01b also recovered interbedded siliciclastic mud, sand and gravel with inclined bedding in its lower 27 cm. This interval indicates an episode of variable but strong current activity before SMO sedimentation became dominant. 14 C ages corrected for old surface ages are consistent with previous dating of marine sediments in Prydz Bay. However, the basal age of AM01b of 28250 ± 230 14 C yr bp probably results from greater contamination by recycled organic matter. Lithology, 14 C surface ages, absolute diatom abundance, and the diatom assemblage are used as indicators of sediment transport pathways beneath the ice shelf. The transport pathways suggested from these indicators do not correspond to previous models of the basal melt/freeze pattern. This indicates that the overturning baroclinic circulation beneath the Amery Ice Shelf (near-bed inflow–surface outflow) is a more important influence on basal melt/freeze and sediment distributions than the barotropic circulation that produces inflow in the east and outflow in the west of the ice front. Localized topographic (ice draft and bed elevation) variations are likely to play a dominant role in the resulting sub-ice shelf melt and sediment distribution. Article in Journal/Newspaper Amery Ice Shelf Antarc* Antarctic Science Antarctica East Antarctica Ice Shelf Prydz Bay Cambridge University Press Antarctic Science 19 4 497 506 |
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Open Polar |
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Cambridge University Press |
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crcambridgeupr |
language |
English |
description |
Abstract Two sediment cores collected from beneath the Amery Ice Shelf, East Antarctica describe the physical sedimentation patterns beneath an existing major embayed ice shelf. Core AM01b was collected from a site of basal freezing, contrasting with core AM02, collected from a site of basal melting. Both cores comprise Holocene siliceous muddy ooze (SMO), however, AM01b also recovered interbedded siliciclastic mud, sand and gravel with inclined bedding in its lower 27 cm. This interval indicates an episode of variable but strong current activity before SMO sedimentation became dominant. 14 C ages corrected for old surface ages are consistent with previous dating of marine sediments in Prydz Bay. However, the basal age of AM01b of 28250 ± 230 14 C yr bp probably results from greater contamination by recycled organic matter. Lithology, 14 C surface ages, absolute diatom abundance, and the diatom assemblage are used as indicators of sediment transport pathways beneath the ice shelf. The transport pathways suggested from these indicators do not correspond to previous models of the basal melt/freeze pattern. This indicates that the overturning baroclinic circulation beneath the Amery Ice Shelf (near-bed inflow–surface outflow) is a more important influence on basal melt/freeze and sediment distributions than the barotropic circulation that produces inflow in the east and outflow in the west of the ice front. Localized topographic (ice draft and bed elevation) variations are likely to play a dominant role in the resulting sub-ice shelf melt and sediment distribution. |
format |
Article in Journal/Newspaper |
author |
Hemer, M.A. Post, A.L. O'Brien, P.E. Craven, M. Truswell, E.M. Roberts, D. Harris, P.T. |
spellingShingle |
Hemer, M.A. Post, A.L. O'Brien, P.E. Craven, M. Truswell, E.M. Roberts, D. Harris, P.T. Sedimentological signatures of the sub-Amery Ice Shelf circulation |
author_facet |
Hemer, M.A. Post, A.L. O'Brien, P.E. Craven, M. Truswell, E.M. Roberts, D. Harris, P.T. |
author_sort |
Hemer, M.A. |
title |
Sedimentological signatures of the sub-Amery Ice Shelf circulation |
title_short |
Sedimentological signatures of the sub-Amery Ice Shelf circulation |
title_full |
Sedimentological signatures of the sub-Amery Ice Shelf circulation |
title_fullStr |
Sedimentological signatures of the sub-Amery Ice Shelf circulation |
title_full_unstemmed |
Sedimentological signatures of the sub-Amery Ice Shelf circulation |
title_sort |
sedimentological signatures of the sub-amery ice shelf circulation |
publisher |
Cambridge University Press (CUP) |
publishDate |
2007 |
url |
http://dx.doi.org/10.1017/s0954102007000697 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102007000697 |
genre |
Amery Ice Shelf Antarc* Antarctic Science Antarctica East Antarctica Ice Shelf Prydz Bay |
genre_facet |
Amery Ice Shelf Antarc* Antarctic Science Antarctica East Antarctica Ice Shelf Prydz Bay |
op_source |
Antarctic Science volume 19, issue 4, page 497-506 ISSN 0954-1020 1365-2079 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0954102007000697 |
container_title |
Antarctic Science |
container_volume |
19 |
container_issue |
4 |
container_start_page |
497 |
op_container_end_page |
506 |
_version_ |
1810474756500094976 |