Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea
The ancestral South Sandwich arc (ASSA) records evidence of Oligocene – Miocene intra-oceanic island arc volcanism in the central Scotia Sea and potentially formed an important topographic barrier to deep ocean currents during the early development of the Antarctic Circumpolar Current. New geochemis...
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2021
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Online Access: | http://nora.nerc.ac.uk/id/eprint/530552/ https://www.sciencedirect.com/science/article/pii/S0921818121002009 |
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ftnerc:oai:nora.nerc.ac.uk:530552 2023-05-15T13:41:45+02:00 Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea Riley, Teal R. Burton-Johnson, Alex Leat, Philip T. Hogan, Kelly A. Halton, Alison M. 2021-10 http://nora.nerc.ac.uk/id/eprint/530552/ https://www.sciencedirect.com/science/article/pii/S0921818121002009 unknown Elsevier Riley, Teal R. orcid:0000-0002-3333-5021 Burton-Johnson, Alex orcid:0000-0003-2208-0075 Leat, Philip T.; Hogan, Kelly A. orcid:0000-0002-1256-8010 Halton, Alison M. 2021 Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea. Global and Planetary Change, 205, 103615. 12, pp. https://doi.org/10.1016/j.gloplacha.2021.103615 <https://doi.org/10.1016/j.gloplacha.2021.103615> Publication - Article PeerReviewed 2021 ftnerc https://doi.org/10.1016/j.gloplacha.2021.103615 2023-02-04T19:52:16Z The ancestral South Sandwich arc (ASSA) records evidence of Oligocene – Miocene intra-oceanic island arc volcanism in the central Scotia Sea and potentially formed an important topographic barrier to deep ocean currents during the early development of the Antarctic Circumpolar Current. New geochemistry and geochronology of dredged basaltic samples from multiple sites across Discovery Bank, in the southern part of the ASSA, provide key information about this poorly understood volcanic arc in the Scotia Sea. Two new 40Arsingle bond39Ar ages confirm volcanism was active in the Discovery Bank segment from 14 to 10 Ma, overlapping with the initial phase of spreading along the East Scotia Ridge. These ages are younger than previously determined for the ASSA and the island arc chain would have influenced deep ocean pathways in the southern Scotia Sea during the mid-Miocene. Geochemical analysis indicates that magmatism was derived from a depleted asthenospheric source, modified by subduction, akin to the present day South Sandwich island arc. Evidence from across Discovery Bank suggests that arc volcanism developed on pre-existing basaltic crust potentially related to Weddell Sea subduction, although the submerged bank is dominated by Miocene arc volcanic rocks. Evidence for an intra-oceanic island arc setting is also provided by the identification and imaging of a linear chain of rear-arc seamounts, characteristic of several volcanic centres in the present day South sandwich island arc. Mafic volcanic rocks, including ultramafic lithologies, from the neighbouring Bruce Bank topographic high have also been investigated and are demonstrated to have been generated in a different tectonic setting to the volcanic rocks of Discovery Bank. They are interpreted to be associated with the opening of Scan Basin during the Late Eocene, or potentially distal evidence of the gabbroic Pacific Margin Anomaly. Article in Journal/Newspaper Antarc* Antarctic Scotia Sea Weddell Sea Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic Weddell Sea Scotia Sea Pacific Weddell South Scotia Ridge ENVELOPE(-46.500,-46.500,-60.000,-60.000) East Scotia Ridge ENVELOPE(-29.250,-29.250,-57.917,-57.917) Discovery Bank ENVELOPE(72.833,72.833,-51.250,-51.250) Global and Planetary Change 205 103615 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
The ancestral South Sandwich arc (ASSA) records evidence of Oligocene – Miocene intra-oceanic island arc volcanism in the central Scotia Sea and potentially formed an important topographic barrier to deep ocean currents during the early development of the Antarctic Circumpolar Current. New geochemistry and geochronology of dredged basaltic samples from multiple sites across Discovery Bank, in the southern part of the ASSA, provide key information about this poorly understood volcanic arc in the Scotia Sea. Two new 40Arsingle bond39Ar ages confirm volcanism was active in the Discovery Bank segment from 14 to 10 Ma, overlapping with the initial phase of spreading along the East Scotia Ridge. These ages are younger than previously determined for the ASSA and the island arc chain would have influenced deep ocean pathways in the southern Scotia Sea during the mid-Miocene. Geochemical analysis indicates that magmatism was derived from a depleted asthenospheric source, modified by subduction, akin to the present day South Sandwich island arc. Evidence from across Discovery Bank suggests that arc volcanism developed on pre-existing basaltic crust potentially related to Weddell Sea subduction, although the submerged bank is dominated by Miocene arc volcanic rocks. Evidence for an intra-oceanic island arc setting is also provided by the identification and imaging of a linear chain of rear-arc seamounts, characteristic of several volcanic centres in the present day South sandwich island arc. Mafic volcanic rocks, including ultramafic lithologies, from the neighbouring Bruce Bank topographic high have also been investigated and are demonstrated to have been generated in a different tectonic setting to the volcanic rocks of Discovery Bank. They are interpreted to be associated with the opening of Scan Basin during the Late Eocene, or potentially distal evidence of the gabbroic Pacific Margin Anomaly. |
format |
Article in Journal/Newspaper |
author |
Riley, Teal R. Burton-Johnson, Alex Leat, Philip T. Hogan, Kelly A. Halton, Alison M. |
spellingShingle |
Riley, Teal R. Burton-Johnson, Alex Leat, Philip T. Hogan, Kelly A. Halton, Alison M. Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea |
author_facet |
Riley, Teal R. Burton-Johnson, Alex Leat, Philip T. Hogan, Kelly A. Halton, Alison M. |
author_sort |
Riley, Teal R. |
title |
Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea |
title_short |
Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea |
title_full |
Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea |
title_fullStr |
Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea |
title_full_unstemmed |
Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea |
title_sort |
geochronology and geochemistry of the south scotia ridge: miocene island arc volcanism of the scotia sea |
publisher |
Elsevier |
publishDate |
2021 |
url |
http://nora.nerc.ac.uk/id/eprint/530552/ https://www.sciencedirect.com/science/article/pii/S0921818121002009 |
long_lat |
ENVELOPE(-46.500,-46.500,-60.000,-60.000) ENVELOPE(-29.250,-29.250,-57.917,-57.917) ENVELOPE(72.833,72.833,-51.250,-51.250) |
geographic |
Antarctic The Antarctic Weddell Sea Scotia Sea Pacific Weddell South Scotia Ridge East Scotia Ridge Discovery Bank |
geographic_facet |
Antarctic The Antarctic Weddell Sea Scotia Sea Pacific Weddell South Scotia Ridge East Scotia Ridge Discovery Bank |
genre |
Antarc* Antarctic Scotia Sea Weddell Sea |
genre_facet |
Antarc* Antarctic Scotia Sea Weddell Sea |
op_relation |
Riley, Teal R. orcid:0000-0002-3333-5021 Burton-Johnson, Alex orcid:0000-0003-2208-0075 Leat, Philip T.; Hogan, Kelly A. orcid:0000-0002-1256-8010 Halton, Alison M. 2021 Geochronology and geochemistry of the South Scotia Ridge: Miocene island arc volcanism of the Scotia Sea. Global and Planetary Change, 205, 103615. 12, pp. https://doi.org/10.1016/j.gloplacha.2021.103615 <https://doi.org/10.1016/j.gloplacha.2021.103615> |
op_doi |
https://doi.org/10.1016/j.gloplacha.2021.103615 |
container_title |
Global and Planetary Change |
container_volume |
205 |
container_start_page |
103615 |
_version_ |
1766157469818552320 |