Shallow Seafloor Gas emissions Near Heard and McDonald Islands on the Kerguelen Plateau, Southern Indian Ocean
Abstract Bubble emission mechanisms from submerged large igneous provinces remains enigmatic. The Kerguelen Plateau, a large igneous province in the southern Indian Ocean, has a long sustained history of active volcanism and glacial/interglacial cycles of sedimentation, both of which may cause seafl...
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American Geophysical Union (AGU)
2020
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Online Access: | https://doi.org/10.1029/2019EA000695 https://doaj.org/article/6bb859cd294f45f1a3a74955b9e1fed6 |
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ftdoajarticles:oai:doaj.org/article:6bb859cd294f45f1a3a74955b9e1fed6 2023-05-15T16:33:54+02:00 Shallow Seafloor Gas emissions Near Heard and McDonald Islands on the Kerguelen Plateau, Southern Indian Ocean E. A. Spain S. C. Johnson B. Hutton J. M. Whittaker V. Lucieer S. J. Watson J. M. Fox J. Lupton R. Arculus A. Bradney M. F. Coffin 2020-03-01T00:00:00Z https://doi.org/10.1029/2019EA000695 https://doaj.org/article/6bb859cd294f45f1a3a74955b9e1fed6 EN eng American Geophysical Union (AGU) https://doi.org/10.1029/2019EA000695 https://doaj.org/toc/2333-5084 2333-5084 doi:10.1029/2019EA000695 https://doaj.org/article/6bb859cd294f45f1a3a74955b9e1fed6 Earth and Space Science, Vol 7, Iss 3, Pp n/a-n/a (2020) Large Igneous Province hydroacoustic flares cold methane seep shallow hydrothermal geothermal gas bubbles Astronomy QB1-991 Geology QE1-996.5 article 2020 ftdoajarticles https://doi.org/10.1029/2019EA000695 2022-12-31T04:58:41Z Abstract Bubble emission mechanisms from submerged large igneous provinces remains enigmatic. The Kerguelen Plateau, a large igneous province 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 underexplored volcanically active Heard Island and McDonald Islands on the Central Kerguelen Plateau. Flares were observed with a split‐beam echosounder and characterized using multifrequency decibel differencing. Deep‐tow camera footage, water properties, water column δ3He, subbottom 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 subbottom acoustic blanking in thick sediment, muted 3He signal, and δ13C and δ34S fractionation factors, suggest that Heard Island 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. 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. Article in Journal/Newspaper Heard Island McDonald Islands Directory of Open Access Journals: DOAJ Articles Kerguelen Heard Island Indian Heard Island ENVELOPE(73.510,73.510,-53.117,-53.117) Heard ENVELOPE(73.510,73.510,-53.117,-53.117) McDonald Islands ENVELOPE(72.600,72.600,-53.033,-53.033) Earth and Space Science 7 3 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Large Igneous Province hydroacoustic flares cold methane seep shallow hydrothermal geothermal gas bubbles Astronomy QB1-991 Geology QE1-996.5 |
spellingShingle |
Large Igneous Province hydroacoustic flares cold methane seep shallow hydrothermal geothermal gas bubbles Astronomy QB1-991 Geology QE1-996.5 E. A. Spain S. C. Johnson B. Hutton J. M. Whittaker V. Lucieer S. J. Watson J. M. Fox J. Lupton R. Arculus A. Bradney M. F. Coffin 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 Astronomy QB1-991 Geology QE1-996.5 |
description |
Abstract Bubble emission mechanisms from submerged large igneous provinces remains enigmatic. The Kerguelen Plateau, a large igneous province 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 underexplored volcanically active Heard Island and McDonald Islands on the Central Kerguelen Plateau. Flares were observed with a split‐beam echosounder and characterized using multifrequency decibel differencing. Deep‐tow camera footage, water properties, water column δ3He, subbottom 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 subbottom acoustic blanking in thick sediment, muted 3He signal, and δ13C and δ34S fractionation factors, suggest that Heard Island 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. 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. |
format |
Article in Journal/Newspaper |
author |
E. A. Spain S. C. Johnson B. Hutton J. M. Whittaker V. Lucieer S. J. Watson J. M. Fox J. Lupton R. Arculus A. Bradney M. F. Coffin |
author_facet |
E. A. Spain S. C. Johnson B. Hutton J. M. Whittaker V. Lucieer S. J. Watson J. M. Fox J. Lupton R. Arculus A. Bradney M. F. Coffin |
author_sort |
E. A. Spain |
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 (AGU) |
publishDate |
2020 |
url |
https://doi.org/10.1029/2019EA000695 https://doaj.org/article/6bb859cd294f45f1a3a74955b9e1fed6 |
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 |
Kerguelen Heard Island Indian Heard Island Heard McDonald Islands |
geographic_facet |
Kerguelen Heard Island Indian Heard Island Heard McDonald Islands |
genre |
Heard Island McDonald Islands |
genre_facet |
Heard Island McDonald Islands |
op_source |
Earth and Space Science, Vol 7, Iss 3, Pp n/a-n/a (2020) |
op_relation |
https://doi.org/10.1029/2019EA000695 https://doaj.org/toc/2333-5084 2333-5084 doi:10.1029/2019EA000695 https://doaj.org/article/6bb859cd294f45f1a3a74955b9e1fed6 |
op_doi |
https://doi.org/10.1029/2019EA000695 |
container_title |
Earth and Space Science |
container_volume |
7 |
container_issue |
3 |
_version_ |
1766023638059843584 |