Shallow seafloor gas emissions near Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean
Bubble emission mechanisms from submerged Large Igneous Provinces (LIPs) remains enigmatic. The Kerguelen Plateau, a LIP in the southern Indian Ocean, has a long‐sustained history of active volcanism and glacial/interglacial cycles of sedimentation, both of which may cause seafloor bubble production...
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American Geophysical Union
2020
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Online Access: | http://hdl.handle.net/10197/11491 https://doi.org/10.1029/2019ea000695 |
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ftunivcolldublin:oai:researchrepository.ucd.ie:10197/11491 2023-05-15T13:33:47+02:00 Shallow seafloor gas emissions near Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean Spain, Erica A. Johnson, Sean C. Hutton, B. 2020-08-25T10:17:02Z http://hdl.handle.net/10197/11491 https://doi.org/10.1029/2019ea000695 en eng American Geophysical Union Earth and Space Science 2333-5084 http://hdl.handle.net/10197/11491 7 3 1 19 doi:10.1029/2019ea000695 4338 SR140300001 DE140100376 DP180102280 This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. CC-BY-NC-ND Large Igneous province Hydroacoustic flares Cold methane seep Shallow hydrothermal Geothermal Gas bubbles Journal Article 2020 ftunivcolldublin https://doi.org/10.1029/2019ea000695 2022-04-08T14:19:40Z Bubble emission mechanisms from submerged Large Igneous Provinces (LIPs) remains enigmatic. The Kerguelen Plateau, a LIP in the southern Indian Ocean, has a long‐sustained history of active volcanism and glacial/interglacial cycles of sedimentation, both of which may cause seafloor bubble production. We present the results of hydroacoustic flare observations around the under‐explored volcanically‐active Heard Island and McDonald Islands on the Central Kerguelen Plateau. Flares were observed with a split‐beam echosounder and characterized using multi‐frequency decibel differencing. Deep‐tow camera footage, water properties, water‐column δ3He, sub‐bottom profile, and sediment δ13C and δ34S data were analyzed to consider flare mechanisms. Excess δ3He near McDonald Islands seeps, indicating mantle‐derived input, suggests proximal hydrothermal activity; McDonald Islands flares may thus indicate CO2, methane, and other minor gas bubbles associated with shallow diffuse hydrothermal venting. The Heard Island seep environment, with sub‐bottom acoustic blanking in thick sediment, muted 3He signal, and δ13C and δ34S fractionation factors, suggest Heard seeps may either be methane gas (possibly both shallow biogenic methane and deeper‐sourced thermogenic methane related to geothermal heat from onshore volcanism) or a combination of methane and CO2, such as seen in sediment‐hosted geothermal systems (Procesi et al., 2019). These data provide the first evidence of submarine gas escape on the Central Kerguelen Plateau and expand our understanding of seafloor processes and carbon cycling in the data‐poor southern Indian Ocean. Extensive sedimentation of the Kerguelen Plateau and additional zones of submarine volcanic activity mean additional seeps or vents may lie outside the small survey area proximal to the islands. Science Foundation Ireland Australian Antarctic Science Program Australian Research Council Australian Government Article in Journal/Newspaper Antarc* Antarctic Heard Island McDonald Islands University College Dublin: Research Repository UCD Antarctic Heard ENVELOPE(73.510,73.510,-53.117,-53.117) Heard Island Heard Island ENVELOPE(73.510,73.510,-53.117,-53.117) Indian Kerguelen McDonald Islands ENVELOPE(72.600,72.600,-53.033,-53.033) Earth and Space Science 7 3 |
institution |
Open Polar |
collection |
University College Dublin: Research Repository UCD |
op_collection_id |
ftunivcolldublin |
language |
English |
topic |
Large Igneous province Hydroacoustic flares Cold methane seep Shallow hydrothermal Geothermal Gas bubbles |
spellingShingle |
Large Igneous province Hydroacoustic flares Cold methane seep Shallow hydrothermal Geothermal Gas bubbles Spain, Erica A. Johnson, Sean C. Hutton, B. Shallow seafloor gas emissions near Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean |
topic_facet |
Large Igneous province Hydroacoustic flares Cold methane seep Shallow hydrothermal Geothermal Gas bubbles |
description |
Bubble emission mechanisms from submerged Large Igneous Provinces (LIPs) remains enigmatic. The Kerguelen Plateau, a LIP in the southern Indian Ocean, has a long‐sustained history of active volcanism and glacial/interglacial cycles of sedimentation, both of which may cause seafloor bubble production. We present the results of hydroacoustic flare observations around the under‐explored volcanically‐active Heard Island and McDonald Islands on the Central Kerguelen Plateau. Flares were observed with a split‐beam echosounder and characterized using multi‐frequency decibel differencing. Deep‐tow camera footage, water properties, water‐column δ3He, sub‐bottom profile, and sediment δ13C and δ34S data were analyzed to consider flare mechanisms. Excess δ3He near McDonald Islands seeps, indicating mantle‐derived input, suggests proximal hydrothermal activity; McDonald Islands flares may thus indicate CO2, methane, and other minor gas bubbles associated with shallow diffuse hydrothermal venting. The Heard Island seep environment, with sub‐bottom acoustic blanking in thick sediment, muted 3He signal, and δ13C and δ34S fractionation factors, suggest Heard seeps may either be methane gas (possibly both shallow biogenic methane and deeper‐sourced thermogenic methane related to geothermal heat from onshore volcanism) or a combination of methane and CO2, such as seen in sediment‐hosted geothermal systems (Procesi et al., 2019). These data provide the first evidence of submarine gas escape on the Central Kerguelen Plateau and expand our understanding of seafloor processes and carbon cycling in the data‐poor southern Indian Ocean. Extensive sedimentation of the Kerguelen Plateau and additional zones of submarine volcanic activity mean additional seeps or vents may lie outside the small survey area proximal to the islands. Science Foundation Ireland Australian Antarctic Science Program Australian Research Council Australian Government |
format |
Article in Journal/Newspaper |
author |
Spain, Erica A. Johnson, Sean C. Hutton, B. |
author_facet |
Spain, Erica A. Johnson, Sean C. Hutton, B. |
author_sort |
Spain, Erica A. |
title |
Shallow seafloor gas emissions near Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean |
title_short |
Shallow seafloor gas emissions near Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean |
title_full |
Shallow seafloor gas emissions near Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean |
title_fullStr |
Shallow seafloor gas emissions near Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean |
title_full_unstemmed |
Shallow seafloor gas emissions near Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean |
title_sort |
shallow seafloor gas emissions near heard and mcdonald islands on the kerguelen plateau, southern indian ocean |
publisher |
American Geophysical Union |
publishDate |
2020 |
url |
http://hdl.handle.net/10197/11491 https://doi.org/10.1029/2019ea000695 |
long_lat |
ENVELOPE(73.510,73.510,-53.117,-53.117) ENVELOPE(73.510,73.510,-53.117,-53.117) ENVELOPE(72.600,72.600,-53.033,-53.033) |
geographic |
Antarctic Heard Heard Island Heard Island Indian Kerguelen McDonald Islands |
geographic_facet |
Antarctic Heard Heard Island Heard Island Indian Kerguelen McDonald Islands |
genre |
Antarc* Antarctic Heard Island McDonald Islands |
genre_facet |
Antarc* Antarctic Heard Island McDonald Islands |
op_relation |
Earth and Space Science 2333-5084 http://hdl.handle.net/10197/11491 7 3 1 19 doi:10.1029/2019ea000695 4338 SR140300001 DE140100376 DP180102280 |
op_rights |
This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1029/2019ea000695 |
container_title |
Earth and Space Science |
container_volume |
7 |
container_issue |
3 |
_version_ |
1766046080545325056 |