Cretaceous – Paleogene tectonic reconstructions of the South Scotia Ridge and implications for the initiation of subduction in the Scotia Sea

Riley, Teal R. ORCID: https://orcid.org/0000-0002-3333-5021; Burton-Johnson, Alex ORCID: https://orcid.org/0000-0003-2208-0075; Hogan, Kelly A. ORCID: https://orcid.org/0000-0002-1256-8010; Carter, Andrew; Leat, Philip T.. 2023 Cretaceous – Paleogene tectonic reconstructions of the South Scotia Ridge and implications for the initiation of subduction in the Scotia Sea. Journal of the Geological Society, 180 (4), jgs2023-013. 10, pp. https://doi.org/10.1144/jgs2023-013

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Text (Open Access) © 2023 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/ licenses/by/4.0/). Published by The Geological Society of London. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics jgs2023-013.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (9MB) | Preview

Abstract/Summary

The Cenozoic development of the Scotia Sea and opening of Drake Passage led to the dispersal of crustal blocks of the North and South Scotia ridges that today have a strong influence on the pathway of the Antarctic circumpolar current. The pre-translation positions of the crustal fragments of the Scotia ridges are uncertain, with correlations to both the Antarctic and South American plates. We present direct geochronology (40Ar/39Ar) from Bruce and Jane banks of the South Scotia Ridge that yield Late Cretaceous – Paleogene ages indicating a pre-translation magmatic history. Basaltic magmatism from Bruce Bank is calc-alkaline, akin to Cenozoic magmatism of the South Orkney microcontinent and the South Shetlands Islands, and in agreement with pre-translation tectonic models that place the crustal blocks of the South Scotia Ridge adjacent to the northern Antarctic Peninsula arc. The intra-oceanic arc magmatism at Jane Bank is Late Cretaceous in age (97.2 ± 1.1 Ma), and is not consistent with models suggesting a Miocene origin as part of the ancestral South Sandwich arc. The development of westward-directed subduction adjacent to Jane Bank is predicted in some tectonic models as a consequence of Late Cretaceous plate dynamics that developed prior to the Oligocene – Miocene ancestral arc.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1144/jgs2023-013
ISSN:	0016-7649
Related URLs:	Dataset
Date made live:	25 May 2023 15:49 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/533897

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