Magnetic fabric from Quaternary volcanic edifices in the extensional Bransfield Basin: internal structure of Penguin and Bridgeman islands (South Shetlands archipelago, Antarctica)
SUMMARY Studying the magnetic fabric in volcanic edifices, particularly lava flows from recent eruptions, allows us to understand the orientation distribution of the minerals related to the flow direction and properly characterize older and/or eroded flows. In this work, the magnetic fabric from rec...
Published in: | Geophysical Journal International |
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Oxford University Press (OUP)
2021
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Online Access: | http://dx.doi.org/10.1093/gji/ggab177 http://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggab177/37746747/ggab177.pdf http://academic.oup.com/gji/article-pdf/226/2/1368/38130022/ggab177.pdf |
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croxfordunivpr:10.1093/gji/ggab177 2023-05-15T14:06:57+02:00 Magnetic fabric from Quaternary volcanic edifices in the extensional Bransfield Basin: internal structure of Penguin and Bridgeman islands (South Shetlands archipelago, Antarctica) Oliva-Urcia, B López-Martínez, J Maestro, A Gil, A Schmid, T Lambán, L J Galé, C Ubide, T Lago, M Universidad de Zaragoza 2021 http://dx.doi.org/10.1093/gji/ggab177 http://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggab177/37746747/ggab177.pdf http://academic.oup.com/gji/article-pdf/226/2/1368/38130022/ggab177.pdf en eng Oxford University Press (OUP) https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model Geophysical Journal International volume 226, issue 2, page 1368-1389 ISSN 0956-540X 1365-246X Geochemistry and Petrology Geophysics journal-article 2021 croxfordunivpr https://doi.org/10.1093/gji/ggab177 2022-12-30T10:34:38Z SUMMARY Studying the magnetic fabric in volcanic edifices, particularly lava flows from recent eruptions, allows us to understand the orientation distribution of the minerals related to the flow direction and properly characterize older and/or eroded flows. In this work, the magnetic fabric from recent (Quaternary) lava flows (slightly inclined in seven sites and plateau lavas in two sites), pyroclastic deposits (two sites from a scoria cone) and volcanic cones, domes and plugs (three sites) from Penguin and Bridgeman islands, located in the Bransfield backarc basin, are presented. The volcanism in the two islands is related to rifting occurring due to the opening of the Bransfield Strait, between the South Shetlands archipelago and the Antarctic Peninsula. The direction of flow of magmatic material is unknown. Rock magnetic analyses, low temperature measurements and electron microscope observations (back-scattered electron imaging and Energy Dispersive X-ray analyses) reveal a Ti-poor magnetite (and maghemite) as the main carrier of the magnetic fabric. Hematite may be present in some samples. Samples from the centre of the lavas reveal a magnetic lineation either parallel or imbricated with respect to the flow plane, whereas in the plateau lavas the magnetic lineation is contained within the subhorizontal plane except in vesicle-rich samples, where imbrication occurs. The magnetic lineation indicates a varied flow direction in Bridgeman Island with respect to the spreading Bransfield Basin axis. The flow direction in the plateau lavas on Penguin Island is deduced from the imbrication of the magnetic fabric in the more vesicular parts, suggesting a SE–NW flow. The volcanic domes are also imbricated with respect to an upward flow, and the bombs show scattered distribution. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctica Bransfield Strait Bridgeman Island Penguin Island Oxford University Press (via Crossref) Antarctic Antarctic Peninsula Bransfield Strait Bridgeman ENVELOPE(-56.733,-56.733,-62.067,-62.067) Bridgeman Island ENVELOPE(-56.712,-56.712,-62.064,-62.064) Penguin Island ENVELOPE(-57.926,-57.926,-62.102,-62.102) The Antarctic Geophysical Journal International 226 2 1368 1389 |
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Open Polar |
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Oxford University Press (via Crossref) |
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croxfordunivpr |
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English |
topic |
Geochemistry and Petrology Geophysics |
spellingShingle |
Geochemistry and Petrology Geophysics Oliva-Urcia, B López-Martínez, J Maestro, A Gil, A Schmid, T Lambán, L J Galé, C Ubide, T Lago, M Magnetic fabric from Quaternary volcanic edifices in the extensional Bransfield Basin: internal structure of Penguin and Bridgeman islands (South Shetlands archipelago, Antarctica) |
topic_facet |
Geochemistry and Petrology Geophysics |
description |
SUMMARY Studying the magnetic fabric in volcanic edifices, particularly lava flows from recent eruptions, allows us to understand the orientation distribution of the minerals related to the flow direction and properly characterize older and/or eroded flows. In this work, the magnetic fabric from recent (Quaternary) lava flows (slightly inclined in seven sites and plateau lavas in two sites), pyroclastic deposits (two sites from a scoria cone) and volcanic cones, domes and plugs (three sites) from Penguin and Bridgeman islands, located in the Bransfield backarc basin, are presented. The volcanism in the two islands is related to rifting occurring due to the opening of the Bransfield Strait, between the South Shetlands archipelago and the Antarctic Peninsula. The direction of flow of magmatic material is unknown. Rock magnetic analyses, low temperature measurements and electron microscope observations (back-scattered electron imaging and Energy Dispersive X-ray analyses) reveal a Ti-poor magnetite (and maghemite) as the main carrier of the magnetic fabric. Hematite may be present in some samples. Samples from the centre of the lavas reveal a magnetic lineation either parallel or imbricated with respect to the flow plane, whereas in the plateau lavas the magnetic lineation is contained within the subhorizontal plane except in vesicle-rich samples, where imbrication occurs. The magnetic lineation indicates a varied flow direction in Bridgeman Island with respect to the spreading Bransfield Basin axis. The flow direction in the plateau lavas on Penguin Island is deduced from the imbrication of the magnetic fabric in the more vesicular parts, suggesting a SE–NW flow. The volcanic domes are also imbricated with respect to an upward flow, and the bombs show scattered distribution. |
author2 |
Universidad de Zaragoza |
format |
Article in Journal/Newspaper |
author |
Oliva-Urcia, B López-Martínez, J Maestro, A Gil, A Schmid, T Lambán, L J Galé, C Ubide, T Lago, M |
author_facet |
Oliva-Urcia, B López-Martínez, J Maestro, A Gil, A Schmid, T Lambán, L J Galé, C Ubide, T Lago, M |
author_sort |
Oliva-Urcia, B |
title |
Magnetic fabric from Quaternary volcanic edifices in the extensional Bransfield Basin: internal structure of Penguin and Bridgeman islands (South Shetlands archipelago, Antarctica) |
title_short |
Magnetic fabric from Quaternary volcanic edifices in the extensional Bransfield Basin: internal structure of Penguin and Bridgeman islands (South Shetlands archipelago, Antarctica) |
title_full |
Magnetic fabric from Quaternary volcanic edifices in the extensional Bransfield Basin: internal structure of Penguin and Bridgeman islands (South Shetlands archipelago, Antarctica) |
title_fullStr |
Magnetic fabric from Quaternary volcanic edifices in the extensional Bransfield Basin: internal structure of Penguin and Bridgeman islands (South Shetlands archipelago, Antarctica) |
title_full_unstemmed |
Magnetic fabric from Quaternary volcanic edifices in the extensional Bransfield Basin: internal structure of Penguin and Bridgeman islands (South Shetlands archipelago, Antarctica) |
title_sort |
magnetic fabric from quaternary volcanic edifices in the extensional bransfield basin: internal structure of penguin and bridgeman islands (south shetlands archipelago, antarctica) |
publisher |
Oxford University Press (OUP) |
publishDate |
2021 |
url |
http://dx.doi.org/10.1093/gji/ggab177 http://academic.oup.com/gji/advance-article-pdf/doi/10.1093/gji/ggab177/37746747/ggab177.pdf http://academic.oup.com/gji/article-pdf/226/2/1368/38130022/ggab177.pdf |
long_lat |
ENVELOPE(-56.733,-56.733,-62.067,-62.067) ENVELOPE(-56.712,-56.712,-62.064,-62.064) ENVELOPE(-57.926,-57.926,-62.102,-62.102) |
geographic |
Antarctic Antarctic Peninsula Bransfield Strait Bridgeman Bridgeman Island Penguin Island The Antarctic |
geographic_facet |
Antarctic Antarctic Peninsula Bransfield Strait Bridgeman Bridgeman Island Penguin Island The Antarctic |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Bransfield Strait Bridgeman Island Penguin Island |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Bransfield Strait Bridgeman Island Penguin Island |
op_source |
Geophysical Journal International volume 226, issue 2, page 1368-1389 ISSN 0956-540X 1365-246X |
op_rights |
https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model |
op_doi |
https://doi.org/10.1093/gji/ggab177 |
container_title |
Geophysical Journal International |
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226 |
container_issue |
2 |
container_start_page |
1368 |
op_container_end_page |
1389 |
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1766278945054916608 |