Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica
ABSTRACT We collected ~1300 km of ground-penetrating radar profiles over McMurdo Ice Shelf, Antarctica, using frequencies between 40 and 400 MHz to determine extent, continuity and depth to the brine. We also used profiles to determine meteoric ice thickness and locate englacial features, which may...
Published in: | Annals of Glaciology |
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crcambridgeupr:10.1017/aog.2017.26 2024-06-09T07:38:31+00:00 Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica Campbell, S. Courville, Z. Sinclair, S. Wilner, J. 2017 http://dx.doi.org/10.1017/aog.2017.26 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S026030551700026X en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Annals of Glaciology volume 58, issue 74, page 1-11 ISSN 0260-3055 1727-5644 journal-article 2017 crcambridgeupr https://doi.org/10.1017/aog.2017.26 2024-05-15T13:16:39Z ABSTRACT We collected ~1300 km of ground-penetrating radar profiles over McMurdo Ice Shelf, Antarctica, using frequencies between 40 and 400 MHz to determine extent, continuity and depth to the brine. We also used profiles to determine meteoric ice thickness and locate englacial features, which may suggest ice shelf instability. The brine extends 9–13 km inland from the ice shelf terminus and covers the entire region between Ross, White and Black Islands. Jump unconformities and basal fractures exist in the brine and ice shelf, respectively, suggesting prior fracturing and re-suturing. One 100 MHz profile, the most distal from the ice shelf edge while still being situated over the brine, simultaneously imaged the brine and bottom of meteoric ice. This suggests a negative brine salinity gradient moving away from the terminus. The meteoric ice bottom was also imaged in a few select locations through blue ice in the ablation zone near Black Island. We suggest that brine, sediment-rich ice and poor antenna coupling on rough ice attenuates the signal in this area. When combined with other recent mass-balance and structural glaciology studies of MIS, our results could contribute to one of the most high-resolution physical models of an ice shelf in Antarctica. Article in Journal/Newspaper Annals of Glaciology Antarc* Antarctica Ice Shelf McMurdo Ice Shelf Black Island Cambridge University Press Black Island ENVELOPE(70.100,70.100,-49.440,-49.440) McMurdo Ice Shelf ENVELOPE(166.500,166.500,-78.000,-78.000) Annals of Glaciology 58 74 1 11 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
ABSTRACT We collected ~1300 km of ground-penetrating radar profiles over McMurdo Ice Shelf, Antarctica, using frequencies between 40 and 400 MHz to determine extent, continuity and depth to the brine. We also used profiles to determine meteoric ice thickness and locate englacial features, which may suggest ice shelf instability. The brine extends 9–13 km inland from the ice shelf terminus and covers the entire region between Ross, White and Black Islands. Jump unconformities and basal fractures exist in the brine and ice shelf, respectively, suggesting prior fracturing and re-suturing. One 100 MHz profile, the most distal from the ice shelf edge while still being situated over the brine, simultaneously imaged the brine and bottom of meteoric ice. This suggests a negative brine salinity gradient moving away from the terminus. The meteoric ice bottom was also imaged in a few select locations through blue ice in the ablation zone near Black Island. We suggest that brine, sediment-rich ice and poor antenna coupling on rough ice attenuates the signal in this area. When combined with other recent mass-balance and structural glaciology studies of MIS, our results could contribute to one of the most high-resolution physical models of an ice shelf in Antarctica. |
format |
Article in Journal/Newspaper |
author |
Campbell, S. Courville, Z. Sinclair, S. Wilner, J. |
spellingShingle |
Campbell, S. Courville, Z. Sinclair, S. Wilner, J. Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica |
author_facet |
Campbell, S. Courville, Z. Sinclair, S. Wilner, J. |
author_sort |
Campbell, S. |
title |
Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica |
title_short |
Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica |
title_full |
Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica |
title_fullStr |
Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica |
title_full_unstemmed |
Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica |
title_sort |
brine, englacial structure and basal properties near the terminus of mcmurdo ice shelf, antarctica |
publisher |
Cambridge University Press (CUP) |
publishDate |
2017 |
url |
http://dx.doi.org/10.1017/aog.2017.26 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S026030551700026X |
long_lat |
ENVELOPE(70.100,70.100,-49.440,-49.440) ENVELOPE(166.500,166.500,-78.000,-78.000) |
geographic |
Black Island McMurdo Ice Shelf |
geographic_facet |
Black Island McMurdo Ice Shelf |
genre |
Annals of Glaciology Antarc* Antarctica Ice Shelf McMurdo Ice Shelf Black Island |
genre_facet |
Annals of Glaciology Antarc* Antarctica Ice Shelf McMurdo Ice Shelf Black Island |
op_source |
Annals of Glaciology volume 58, issue 74, page 1-11 ISSN 0260-3055 1727-5644 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/aog.2017.26 |
container_title |
Annals of Glaciology |
container_volume |
58 |
container_issue |
74 |
container_start_page |
1 |
op_container_end_page |
11 |
_version_ |
1801373392093315072 |