Discovery of large-scale buried volcanoes within the Cenozoic succession of the Prawn Platform, offshore Otway Basin, southeastern Australia
Volcanic rocks occur in different types of sedimentary basins, especially those evolving from lithospheric stretching. While volcanoes and other igneous rocks are widespread in the onshore Otway Basin, well-preserved volcanoes have not been documented in the offshore portion of the basin. Here, we a...
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ftunivgeneve:oai:unige.ch:unige:149809 2023-05-15T18:25:53+02:00 Discovery of large-scale buried volcanoes within the Cenozoic succession of the Prawn Platform, offshore Otway Basin, southeastern Australia Niyazi, Yakufu Eruteya,Ovie Warne, Mark Ierodiaconou, Daniel 2021 https://archive-ouverte.unige.ch/unige:149809 eng eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.marpetgeo.2020.104747 unige:149809 https://archive-ouverte.unige.ch/unige:149809 info:eu-repo/semantics/restrictedAccess ISSN: 0264-8172 Marine and Petroleum Geology, Vol. 123, No 104747 (2021) info:eu-repo/classification/ddc/550 Buried volcanoes Igneous sills Seismic reflection data Volcanic seismic facies Offshore Otway Basin Text info:eu-repo/semantics/article Article scientifique info:eu-repo/semantics/publishedVersion 2021 ftunivgeneve https://doi.org/10.1016/j.marpetgeo.2020.104747 2022-02-08T22:30:58Z Volcanic rocks occur in different types of sedimentary basins, especially those evolving from lithospheric stretching. While volcanoes and other igneous rocks are widespread in the onshore Otway Basin, well-preserved volcanoes have not been documented in the offshore portion of the basin. Here, we analysed high-quality 2-D and 3-D seismic reflection datasets to investigate the origin and distribution of the enigmatic, kilometre-scale buried mound-shaped structures in the Prawn Platform, offshore Otway Basin. Detailed seismic characterisation enabled the identification of 19 mounds, ranging from ~90–400 m in height and 1.8–6 km in diameter. Relatively small (~0.2–11 km2) igneous sills are associated with these mounds. Based on their external geometries and internal seismic architectures, we interpret these mounds as dyke-fed shield volcanoes. Distinct seismic facies characterise the buried volcanoes, including the main volcanic eruption centre, tuff cone, and pyroclastic mass-wasting deposits. Interbedded extrusive and sedimentary rocks are mainly observed within volcanoes over 250 m high, and are associated with gullies along their flanks, indicating these volcanoes may have been subject to erosion. The volcanoes occur at three stratigraphic levels: late Eocene (~37 Ma), mid-Oligocene (~27–29 Ma), and early Miocene (~20 Ma), within the age of the Older Volcanics of the southern Australian margin. We propose that this newly discovered volcanism in the offshore Otway Basin was caused by edge-driven convection (similar mechanism to adjacent onshore volcanism), associated with the fast spreading rate of the Southern Ocean since the late Eocene (~40 Ma). The discovery of these buried volcanoes extends our understanding of magmatism in the Otway Basin, especially regarding the offshore extension of the Older Volcanics. Article in Journal/Newspaper Southern Ocean Université de Genève: Archive ouverte UNIGE Southern Ocean Marine and Petroleum Geology 123 104747 |
institution |
Open Polar |
collection |
Université de Genève: Archive ouverte UNIGE |
op_collection_id |
ftunivgeneve |
language |
English |
topic |
info:eu-repo/classification/ddc/550 Buried volcanoes Igneous sills Seismic reflection data Volcanic seismic facies Offshore Otway Basin |
spellingShingle |
info:eu-repo/classification/ddc/550 Buried volcanoes Igneous sills Seismic reflection data Volcanic seismic facies Offshore Otway Basin Niyazi, Yakufu Eruteya,Ovie Warne, Mark Ierodiaconou, Daniel Discovery of large-scale buried volcanoes within the Cenozoic succession of the Prawn Platform, offshore Otway Basin, southeastern Australia |
topic_facet |
info:eu-repo/classification/ddc/550 Buried volcanoes Igneous sills Seismic reflection data Volcanic seismic facies Offshore Otway Basin |
description |
Volcanic rocks occur in different types of sedimentary basins, especially those evolving from lithospheric stretching. While volcanoes and other igneous rocks are widespread in the onshore Otway Basin, well-preserved volcanoes have not been documented in the offshore portion of the basin. Here, we analysed high-quality 2-D and 3-D seismic reflection datasets to investigate the origin and distribution of the enigmatic, kilometre-scale buried mound-shaped structures in the Prawn Platform, offshore Otway Basin. Detailed seismic characterisation enabled the identification of 19 mounds, ranging from ~90–400 m in height and 1.8–6 km in diameter. Relatively small (~0.2–11 km2) igneous sills are associated with these mounds. Based on their external geometries and internal seismic architectures, we interpret these mounds as dyke-fed shield volcanoes. Distinct seismic facies characterise the buried volcanoes, including the main volcanic eruption centre, tuff cone, and pyroclastic mass-wasting deposits. Interbedded extrusive and sedimentary rocks are mainly observed within volcanoes over 250 m high, and are associated with gullies along their flanks, indicating these volcanoes may have been subject to erosion. The volcanoes occur at three stratigraphic levels: late Eocene (~37 Ma), mid-Oligocene (~27–29 Ma), and early Miocene (~20 Ma), within the age of the Older Volcanics of the southern Australian margin. We propose that this newly discovered volcanism in the offshore Otway Basin was caused by edge-driven convection (similar mechanism to adjacent onshore volcanism), associated with the fast spreading rate of the Southern Ocean since the late Eocene (~40 Ma). The discovery of these buried volcanoes extends our understanding of magmatism in the Otway Basin, especially regarding the offshore extension of the Older Volcanics. |
format |
Article in Journal/Newspaper |
author |
Niyazi, Yakufu Eruteya,Ovie Warne, Mark Ierodiaconou, Daniel |
author_facet |
Niyazi, Yakufu Eruteya,Ovie Warne, Mark Ierodiaconou, Daniel |
author_sort |
Niyazi, Yakufu |
title |
Discovery of large-scale buried volcanoes within the Cenozoic succession of the Prawn Platform, offshore Otway Basin, southeastern Australia |
title_short |
Discovery of large-scale buried volcanoes within the Cenozoic succession of the Prawn Platform, offshore Otway Basin, southeastern Australia |
title_full |
Discovery of large-scale buried volcanoes within the Cenozoic succession of the Prawn Platform, offshore Otway Basin, southeastern Australia |
title_fullStr |
Discovery of large-scale buried volcanoes within the Cenozoic succession of the Prawn Platform, offshore Otway Basin, southeastern Australia |
title_full_unstemmed |
Discovery of large-scale buried volcanoes within the Cenozoic succession of the Prawn Platform, offshore Otway Basin, southeastern Australia |
title_sort |
discovery of large-scale buried volcanoes within the cenozoic succession of the prawn platform, offshore otway basin, southeastern australia |
publishDate |
2021 |
url |
https://archive-ouverte.unige.ch/unige:149809 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
ISSN: 0264-8172 Marine and Petroleum Geology, Vol. 123, No 104747 (2021) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.marpetgeo.2020.104747 unige:149809 https://archive-ouverte.unige.ch/unige:149809 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.marpetgeo.2020.104747 |
container_title |
Marine and Petroleum Geology |
container_volume |
123 |
container_start_page |
104747 |
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1766207594042490880 |