Geochronology and geochemistry of the northern Scotia Sea: A revised interpretation of the North and West Scotia ridge junction
Understanding the tectonic evolution of the Scotia Sea is critical to interpreting how ocean gateways developed during the Cenozoic and their influence on ocean circulation patterns and water exchange between the Atlantic and Southern oceans. We examine the geochronology and detrital age history of...
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2019
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ftucl:oai:eprints.ucl.ac.uk.OAI2:10082922 2023-12-24T10:11:31+01:00 Geochronology and geochemistry of the northern Scotia Sea: A revised interpretation of the North and West Scotia ridge junction Riley, TR Carter, A Leat, PT Burton-Johnson, A Bastias, J Spikings, RA Tate, AJ Bristow, CS 2019-07-15 text https://discovery.ucl.ac.uk/id/eprint/10082922/1/Riley%20et%20al2019.pdf https://discovery.ucl.ac.uk/id/eprint/10082922/ eng eng ELSEVIER SCIENCE BV https://discovery.ucl.ac.uk/id/eprint/10082922/1/Riley%20et%20al2019.pdf https://discovery.ucl.ac.uk/id/eprint/10082922/ open Earth and Planetary Science Letters , 518 pp. 136-147. (2019) Scotia Sea Antarctica sea floor spreading geochemistry Drake Passage provenance Article 2019 ftucl 2023-11-27T13:07:28Z Understanding the tectonic evolution of the Scotia Sea is critical to interpreting how ocean gateways developed during the Cenozoic and their influence on ocean circulation patterns and water exchange between the Atlantic and Southern oceans. We examine the geochronology and detrital age history of lithologies from the prominent, submerged Barker Plateau of the North Scotia Ridge. Metasedimentary rocks of the North Scotia Ridge share a strong geological affinity with the Fuegian Andes and South Georgia, indicating a common geological history and no direct affinity to the Antarctic Peninsula. The detrital zircon geochronology indicates that deposition was likely to have taken place during the mid – Late Cretaceous. A tonalite intrusion from the Barker Plateau has been dated at 49.6 ± 0.3 Ma and indicates that magmatism of the Patagonian–Fuegian batholith continued into the Eocene. This was coincident with the very early stages of Drake Passage opening, the expansion of the proto Scotia Sea and reorganization of the Fuegian Andes. The West Scotia Ridge is an extinct spreading center that shaped the Scotia Sea and consists of seven spreading segments separated by prominent transform faults. Spreading was active from 30–6 Ma and ceased with activity on the W7 segment at the junction with the North Scotia Ridge. Reinterpretation of the gravity and magnetic anomalies indicate that the architecture of the W7 spreading segment is distinct to the other segments of the West Scotia Ridge. Basaltic lava samples from the eastern flank of the W7 segment have been dated as Early – mid Cretaceous in age (137–93 Ma) and have a prominent arc geochemical signature indicating that seafloor spreading did not occur on the W7 segment. Instead the W7 segment is likely to represent a downfaulted block of the North Scotia Ridge of the Fuegian Andes continental margin arc, or is potentially related to the putative Cretaceous Central Scotia Sea. Article in Journal/Newspaper Antarc* Antarctic Antarctic Peninsula Antarctica Drake Passage Scotia Sea University College London: UCL Discovery Antarctic The Antarctic Antarctic Peninsula Drake Passage Scotia Sea North Scotia Ridge ENVELOPE(-51.431,-51.431,-53.581,-53.581) West Scotia Ridge ENVELOPE(-56.500,-56.500,-56.833,-56.833) Barker Plateau ENVELOPE(-47.217,-47.217,-53.188,-53.188) |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
Scotia Sea Antarctica sea floor spreading geochemistry Drake Passage provenance |
spellingShingle |
Scotia Sea Antarctica sea floor spreading geochemistry Drake Passage provenance Riley, TR Carter, A Leat, PT Burton-Johnson, A Bastias, J Spikings, RA Tate, AJ Bristow, CS Geochronology and geochemistry of the northern Scotia Sea: A revised interpretation of the North and West Scotia ridge junction |
topic_facet |
Scotia Sea Antarctica sea floor spreading geochemistry Drake Passage provenance |
description |
Understanding the tectonic evolution of the Scotia Sea is critical to interpreting how ocean gateways developed during the Cenozoic and their influence on ocean circulation patterns and water exchange between the Atlantic and Southern oceans. We examine the geochronology and detrital age history of lithologies from the prominent, submerged Barker Plateau of the North Scotia Ridge. Metasedimentary rocks of the North Scotia Ridge share a strong geological affinity with the Fuegian Andes and South Georgia, indicating a common geological history and no direct affinity to the Antarctic Peninsula. The detrital zircon geochronology indicates that deposition was likely to have taken place during the mid – Late Cretaceous. A tonalite intrusion from the Barker Plateau has been dated at 49.6 ± 0.3 Ma and indicates that magmatism of the Patagonian–Fuegian batholith continued into the Eocene. This was coincident with the very early stages of Drake Passage opening, the expansion of the proto Scotia Sea and reorganization of the Fuegian Andes. The West Scotia Ridge is an extinct spreading center that shaped the Scotia Sea and consists of seven spreading segments separated by prominent transform faults. Spreading was active from 30–6 Ma and ceased with activity on the W7 segment at the junction with the North Scotia Ridge. Reinterpretation of the gravity and magnetic anomalies indicate that the architecture of the W7 spreading segment is distinct to the other segments of the West Scotia Ridge. Basaltic lava samples from the eastern flank of the W7 segment have been dated as Early – mid Cretaceous in age (137–93 Ma) and have a prominent arc geochemical signature indicating that seafloor spreading did not occur on the W7 segment. Instead the W7 segment is likely to represent a downfaulted block of the North Scotia Ridge of the Fuegian Andes continental margin arc, or is potentially related to the putative Cretaceous Central Scotia Sea. |
format |
Article in Journal/Newspaper |
author |
Riley, TR Carter, A Leat, PT Burton-Johnson, A Bastias, J Spikings, RA Tate, AJ Bristow, CS |
author_facet |
Riley, TR Carter, A Leat, PT Burton-Johnson, A Bastias, J Spikings, RA Tate, AJ Bristow, CS |
author_sort |
Riley, TR |
title |
Geochronology and geochemistry of the northern Scotia Sea: A revised interpretation of the North and West Scotia ridge junction |
title_short |
Geochronology and geochemistry of the northern Scotia Sea: A revised interpretation of the North and West Scotia ridge junction |
title_full |
Geochronology and geochemistry of the northern Scotia Sea: A revised interpretation of the North and West Scotia ridge junction |
title_fullStr |
Geochronology and geochemistry of the northern Scotia Sea: A revised interpretation of the North and West Scotia ridge junction |
title_full_unstemmed |
Geochronology and geochemistry of the northern Scotia Sea: A revised interpretation of the North and West Scotia ridge junction |
title_sort |
geochronology and geochemistry of the northern scotia sea: a revised interpretation of the north and west scotia ridge junction |
publisher |
ELSEVIER SCIENCE BV |
publishDate |
2019 |
url |
https://discovery.ucl.ac.uk/id/eprint/10082922/1/Riley%20et%20al2019.pdf https://discovery.ucl.ac.uk/id/eprint/10082922/ |
long_lat |
ENVELOPE(-51.431,-51.431,-53.581,-53.581) ENVELOPE(-56.500,-56.500,-56.833,-56.833) ENVELOPE(-47.217,-47.217,-53.188,-53.188) |
geographic |
Antarctic The Antarctic Antarctic Peninsula Drake Passage Scotia Sea North Scotia Ridge West Scotia Ridge Barker Plateau |
geographic_facet |
Antarctic The Antarctic Antarctic Peninsula Drake Passage Scotia Sea North Scotia Ridge West Scotia Ridge Barker Plateau |
genre |
Antarc* Antarctic Antarctic Peninsula Antarctica Drake Passage Scotia Sea |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Antarctica Drake Passage Scotia Sea |
op_source |
Earth and Planetary Science Letters , 518 pp. 136-147. (2019) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/10082922/1/Riley%20et%20al2019.pdf https://discovery.ucl.ac.uk/id/eprint/10082922/ |
op_rights |
open |
_version_ |
1786166253359988736 |