The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying
Sea floor methane vents and seeps direct methane generated by microbial and thermal decompositions of organic matter in sediment into the oceans and atmosphere. Methane vents contribute to ocean acidification, global warming, and providing a long-term (e.g. 500–4000 years; Powell et al., 1998) life-...
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ftnerc:oai:nora.nerc.ac.uk:307555 2023-05-15T17:12:10+02:00 The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying Bangs, Nathan L.B. Hornbach, Matthew J. Berndt, Christian 2011-10-01 http://nora.nerc.ac.uk/id/eprint/307555/ unknown Bangs, Nathan L.B.; Hornbach, Matthew J.; Berndt, Christian. 2011 The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying. Earth and Planetary Science Letters, 310 (1-2). 105-112. https://doi.org/10.1016/j.epsl.2011.06.022 <https://doi.org/10.1016/j.epsl.2011.06.022> Publication - Article PeerReviewed 2011 ftnerc https://doi.org/10.1016/j.epsl.2011.06.022 2023-02-04T19:35:57Z Sea floor methane vents and seeps direct methane generated by microbial and thermal decompositions of organic matter in sediment into the oceans and atmosphere. Methane vents contribute to ocean acidification, global warming, and providing a long-term (e.g. 500–4000 years; Powell et al., 1998) life-sustaining role for unique chemosynthetic biological communities. However, the role methane vents play in both climate change and chemosynthetic life remains controversial primarily because we do not understand long-term methane flux and the mechanisms that control it ( [Milkov et al., 2004], [Shakhova et al., 2010] and [Van Dover, 2000]). Vents are inherently dynamic and flux varies greatly in magnitude and even flow direction over short time periods (hours-to-days), often tidally-driven ( [Boles et al., 2001] and [Tryon et al., 1999]). But, it remains unclear if flux changes at vents occur on the order of the life-cycle of various species within chemosynthetic communities (months, years, to decades [Leifer et al., 2004] and [Torres et al., 2001]) and thus impacts their sustainability. Here, using repeat high-resolution 3D seismic surveys acquired in 2000 and 2008, we demonstrate in 4D that Hydrate Ridge, a vent off the Oregon coast has undergone significant reduction of methane flow and complete interruption in just the past few years. In the subsurface, below a frozen methane hydrate layer, free gas appears to be migrating toward the vent, but currently there is accumulating gas that is unable to reach the seafloor through the gas hydrate layer. At the same time, abundant authigenic carbonates show that the system has been active for several thousands of years. Thus, it is likely that activity has been intermittent because gas hydrates clog the vertical flow pathways feeding the seafloor vent. Back pressure building in the subsurface will ultimately trigger hydrofracturing that will revive fluid-flow to the seafloor. The nature of this mechanism implies regular recurring flow interruptions and methane flux changes ... Article in Journal/Newspaper Methane hydrate Ocean acidification Natural Environment Research Council: NERC Open Research Archive Dover ENVELOPE(-55.753,-55.753,-83.777,-83.777) Earth and Planetary Science Letters 310 1-2 105 112 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
language |
unknown |
description |
Sea floor methane vents and seeps direct methane generated by microbial and thermal decompositions of organic matter in sediment into the oceans and atmosphere. Methane vents contribute to ocean acidification, global warming, and providing a long-term (e.g. 500–4000 years; Powell et al., 1998) life-sustaining role for unique chemosynthetic biological communities. However, the role methane vents play in both climate change and chemosynthetic life remains controversial primarily because we do not understand long-term methane flux and the mechanisms that control it ( [Milkov et al., 2004], [Shakhova et al., 2010] and [Van Dover, 2000]). Vents are inherently dynamic and flux varies greatly in magnitude and even flow direction over short time periods (hours-to-days), often tidally-driven ( [Boles et al., 2001] and [Tryon et al., 1999]). But, it remains unclear if flux changes at vents occur on the order of the life-cycle of various species within chemosynthetic communities (months, years, to decades [Leifer et al., 2004] and [Torres et al., 2001]) and thus impacts their sustainability. Here, using repeat high-resolution 3D seismic surveys acquired in 2000 and 2008, we demonstrate in 4D that Hydrate Ridge, a vent off the Oregon coast has undergone significant reduction of methane flow and complete interruption in just the past few years. In the subsurface, below a frozen methane hydrate layer, free gas appears to be migrating toward the vent, but currently there is accumulating gas that is unable to reach the seafloor through the gas hydrate layer. At the same time, abundant authigenic carbonates show that the system has been active for several thousands of years. Thus, it is likely that activity has been intermittent because gas hydrates clog the vertical flow pathways feeding the seafloor vent. Back pressure building in the subsurface will ultimately trigger hydrofracturing that will revive fluid-flow to the seafloor. The nature of this mechanism implies regular recurring flow interruptions and methane flux changes ... |
format |
Article in Journal/Newspaper |
author |
Bangs, Nathan L.B. Hornbach, Matthew J. Berndt, Christian |
spellingShingle |
Bangs, Nathan L.B. Hornbach, Matthew J. Berndt, Christian The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying |
author_facet |
Bangs, Nathan L.B. Hornbach, Matthew J. Berndt, Christian |
author_sort |
Bangs, Nathan L.B. |
title |
The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying |
title_short |
The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying |
title_full |
The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying |
title_fullStr |
The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying |
title_full_unstemmed |
The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying |
title_sort |
mechanics of intermittent methane venting at south hydrate ridge inferred from 4d seismic surveying |
publishDate |
2011 |
url |
http://nora.nerc.ac.uk/id/eprint/307555/ |
long_lat |
ENVELOPE(-55.753,-55.753,-83.777,-83.777) |
geographic |
Dover |
geographic_facet |
Dover |
genre |
Methane hydrate Ocean acidification |
genre_facet |
Methane hydrate Ocean acidification |
op_relation |
Bangs, Nathan L.B.; Hornbach, Matthew J.; Berndt, Christian. 2011 The mechanics of intermittent methane venting at South Hydrate Ridge inferred from 4D seismic surveying. Earth and Planetary Science Letters, 310 (1-2). 105-112. https://doi.org/10.1016/j.epsl.2011.06.022 <https://doi.org/10.1016/j.epsl.2011.06.022> |
op_doi |
https://doi.org/10.1016/j.epsl.2011.06.022 |
container_title |
Earth and Planetary Science Letters |
container_volume |
310 |
container_issue |
1-2 |
container_start_page |
105 |
op_container_end_page |
112 |
_version_ |
1766068960402341888 |