Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories
The presence of offshore permafrost in the Canadian Beaufort Sea region has previously been identified from seismic and borehole data. The consequence of such permafrost is the possibility of an underlying gas-hydrate stability zone. In this study the authors present the first evidence for the wides...
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Natural Resources Canada
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ftoceanrep:oai:oceanrep.geomar.de:29901 2023-05-15T14:26:53+02:00 Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories Riedel, Michael Taylor, G. Taylor, A. E. Dallimore, S. R. 2015-10 text https://oceanrep.geomar.de/id/eprint/29901/ https://oceanrep.geomar.de/id/eprint/29901/1/cr_2015_08_gsc.pdf https://doi.org/10.4095/296987 en eng Natural Resources Canada https://oceanrep.geomar.de/id/eprint/29901/1/cr_2015_08_gsc.pdf Riedel, M. , Taylor, G., Taylor, A. E. and Dallimore, S. R. (2015) Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories. Open Access . Geological Survey of Canada Current Research, 2015-8 . Natural Resources Canada, 21 pp. DOI 10.4095/296987 <https://doi.org/10.4095/296987>. doi:10.4095/296987 cc_by_3.0 info:eu-repo/semantics/openAccess Report PeerReviewed 2015 ftoceanrep https://doi.org/10.4095/296987 2023-04-07T15:21:05Z The presence of offshore permafrost in the Canadian Beaufort Sea region has previously been identified from seismic and borehole data. The consequence of such permafrost is the possibility of an underlying gas-hydrate stability zone. In this study the authors present the first evidence for the widespread occurrence of gas hydrate in the offshore portion of the Beaufort Shelf using 3-D seismic data. A reflector of opposite polarity relative to the seafloor was identified at a depth of about 1000 m below seafloor that mimics some of the behaviour of the traditionally seen bottom-simulating reflectors in marine gas-hydrate regimes; however, the reflection identified is not truly bottom simulating, as its depth is rather controlled by the rapidly thinning wedge of submerged permafrost. The depth of the reflector decreases with increasing water depth, as predicted from thermal modelling. The reflection crosscuts strata and marks a zone of enhanced reflectivity underneath, possibly originating from free gas that accumulated at this phase boundary over time as the permafrost and associated gas-hydrate stability zones were thinning in response to the transgression. The presence of a clear and widespread gas-hydrate stability field beneath the permafrost has widespread implications on the region, including deep-drilling hazards associated with the presence of free gas, possible overpressure, and lateral migration of fluids and associated expulsion at the seafloor. Report Arctic Arctic Beaufort Sea Northwest Territories permafrost wedge* OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Arctic Beaufort Shelf ENVELOPE(-142.500,-142.500,70.000,70.000) Northwest Territories |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
The presence of offshore permafrost in the Canadian Beaufort Sea region has previously been identified from seismic and borehole data. The consequence of such permafrost is the possibility of an underlying gas-hydrate stability zone. In this study the authors present the first evidence for the widespread occurrence of gas hydrate in the offshore portion of the Beaufort Shelf using 3-D seismic data. A reflector of opposite polarity relative to the seafloor was identified at a depth of about 1000 m below seafloor that mimics some of the behaviour of the traditionally seen bottom-simulating reflectors in marine gas-hydrate regimes; however, the reflection identified is not truly bottom simulating, as its depth is rather controlled by the rapidly thinning wedge of submerged permafrost. The depth of the reflector decreases with increasing water depth, as predicted from thermal modelling. The reflection crosscuts strata and marks a zone of enhanced reflectivity underneath, possibly originating from free gas that accumulated at this phase boundary over time as the permafrost and associated gas-hydrate stability zones were thinning in response to the transgression. The presence of a clear and widespread gas-hydrate stability field beneath the permafrost has widespread implications on the region, including deep-drilling hazards associated with the presence of free gas, possible overpressure, and lateral migration of fluids and associated expulsion at the seafloor. |
format |
Report |
author |
Riedel, Michael Taylor, G. Taylor, A. E. Dallimore, S. R. |
spellingShingle |
Riedel, Michael Taylor, G. Taylor, A. E. Dallimore, S. R. Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories |
author_facet |
Riedel, Michael Taylor, G. Taylor, A. E. Dallimore, S. R. |
author_sort |
Riedel, Michael |
title |
Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories |
title_short |
Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories |
title_full |
Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories |
title_fullStr |
Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories |
title_full_unstemmed |
Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories |
title_sort |
evidence for a deep gas hydrate stability zone associated with submerged permafrost on the canadian arctic beaufort shelf, northwest territories |
publisher |
Natural Resources Canada |
publishDate |
2015 |
url |
https://oceanrep.geomar.de/id/eprint/29901/ https://oceanrep.geomar.de/id/eprint/29901/1/cr_2015_08_gsc.pdf https://doi.org/10.4095/296987 |
long_lat |
ENVELOPE(-142.500,-142.500,70.000,70.000) |
geographic |
Arctic Beaufort Shelf Northwest Territories |
geographic_facet |
Arctic Beaufort Shelf Northwest Territories |
genre |
Arctic Arctic Beaufort Sea Northwest Territories permafrost wedge* |
genre_facet |
Arctic Arctic Beaufort Sea Northwest Territories permafrost wedge* |
op_relation |
https://oceanrep.geomar.de/id/eprint/29901/1/cr_2015_08_gsc.pdf Riedel, M. , Taylor, G., Taylor, A. E. and Dallimore, S. R. (2015) Evidence for a deep gas hydrate stability zone associated with submerged permafrost on the Canadian Arctic Beaufort Shelf, Northwest Territories. Open Access . Geological Survey of Canada Current Research, 2015-8 . Natural Resources Canada, 21 pp. DOI 10.4095/296987 <https://doi.org/10.4095/296987>. doi:10.4095/296987 |
op_rights |
cc_by_3.0 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.4095/296987 |
_version_ |
1766300333363953664 |