Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea
The Harstad Basin is a structural block on the continental shelf of SW Barents Sea where gas hydrates likely occurred below the grounded ice-sheet during the last glaciation and it hosts active gas seepage at numerous seafloor sites. We present an integrated study of fluid flow systems in the Harsta...
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Online Access: | https://oceanrep.geomar.de/id/eprint/47187/ https://oceanrep.geomar.de/id/eprint/47187/1/Cremiere.pdf https://doi.org/10.1016/j.marpetgeo.2018.07.010 |
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ftoceanrep:oai:oceanrep.geomar.de:47187 2023-05-15T15:38:48+02:00 Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea Crémière, Antoine Chand, Shyam Sahy, Diana Thorsnes, Terje Martma, Tõnu Noble, Stephen R. Pedersen, Jon Halvard Brunstad, Harald Lepland, Aivo 2018 text https://oceanrep.geomar.de/id/eprint/47187/ https://oceanrep.geomar.de/id/eprint/47187/1/Cremiere.pdf https://doi.org/10.1016/j.marpetgeo.2018.07.010 en eng Elsevier https://oceanrep.geomar.de/id/eprint/47187/1/Cremiere.pdf Crémière, A. , Chand, S., Sahy, D., Thorsnes, T., Martma, T. , Noble, S. R., Pedersen, J. H., Brunstad, H. and Lepland, A. (2018) Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea. Marine and Petroleum Geology, 98 . pp. 569-581. DOI 10.1016/j.marpetgeo.2018.07.010 <https://doi.org/10.1016/j.marpetgeo.2018.07.010>. doi:10.1016/j.marpetgeo.2018.07.010 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2018 ftoceanrep https://doi.org/10.1016/j.marpetgeo.2018.07.010 2023-04-07T15:46:36Z The Harstad Basin is a structural block on the continental shelf of SW Barents Sea where gas hydrates likely occurred below the grounded ice-sheet during the last glaciation and it hosts active gas seepage at numerous seafloor sites. We present an integrated study of fluid flow systems in the Harstad Basin by combining seismic profile interpretations and gas flare mapping data with the geochemical results obtained on seafloor seeping gas and methane-derived carbonate crusts. More than 190 acoustic gas flares were registered in water column, many of them in association with pockmarks and carbonate crust fields. However, weak or absent seepage observed during remotely operated underwater vehicle transects across many pockmarks and crust fields suggests that seepage activity may have decreased since the last deglaciation. In the western Harstad Basin, seeps of microbial methane occur mainly above Tertiary formations that are pinching out below the glacial sediments. High amplitude seismic anomalies suggest the presence of gas pockets at the base of the glacial sediments and within Tertiary deposits. In contrast, gas seeping in the eastern Harstad Basin originates from a biodegraded thermogenic source tentatively connected to the deeply faulted Mesozoic rocks occurring below glacial sediments. This spatial variability in fluid sources is also recorded in the carbon isotope data of seafloor carbonate crusts, with δ13C values typically between −55 and −42‰ and −40 and −20 ‰VPDB for carbonate crusts associated with microbial and thermogenic fluids, respectively. U-Th chronology combined with the stable isotope data suggests that this discrepancy in fluid sources over a distance of about 20 km has been stable since the last glaciation and highlights the significance of regional underlying geology in mediating fluid supply to the seafloor. Article in Journal/Newspaper Barents Sea Ice Sheet OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Barents Sea Marine and Petroleum Geology 98 569 581 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
The Harstad Basin is a structural block on the continental shelf of SW Barents Sea where gas hydrates likely occurred below the grounded ice-sheet during the last glaciation and it hosts active gas seepage at numerous seafloor sites. We present an integrated study of fluid flow systems in the Harstad Basin by combining seismic profile interpretations and gas flare mapping data with the geochemical results obtained on seafloor seeping gas and methane-derived carbonate crusts. More than 190 acoustic gas flares were registered in water column, many of them in association with pockmarks and carbonate crust fields. However, weak or absent seepage observed during remotely operated underwater vehicle transects across many pockmarks and crust fields suggests that seepage activity may have decreased since the last deglaciation. In the western Harstad Basin, seeps of microbial methane occur mainly above Tertiary formations that are pinching out below the glacial sediments. High amplitude seismic anomalies suggest the presence of gas pockets at the base of the glacial sediments and within Tertiary deposits. In contrast, gas seeping in the eastern Harstad Basin originates from a biodegraded thermogenic source tentatively connected to the deeply faulted Mesozoic rocks occurring below glacial sediments. This spatial variability in fluid sources is also recorded in the carbon isotope data of seafloor carbonate crusts, with δ13C values typically between −55 and −42‰ and −40 and −20 ‰VPDB for carbonate crusts associated with microbial and thermogenic fluids, respectively. U-Th chronology combined with the stable isotope data suggests that this discrepancy in fluid sources over a distance of about 20 km has been stable since the last glaciation and highlights the significance of regional underlying geology in mediating fluid supply to the seafloor. |
format |
Article in Journal/Newspaper |
author |
Crémière, Antoine Chand, Shyam Sahy, Diana Thorsnes, Terje Martma, Tõnu Noble, Stephen R. Pedersen, Jon Halvard Brunstad, Harald Lepland, Aivo |
spellingShingle |
Crémière, Antoine Chand, Shyam Sahy, Diana Thorsnes, Terje Martma, Tõnu Noble, Stephen R. Pedersen, Jon Halvard Brunstad, Harald Lepland, Aivo Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea |
author_facet |
Crémière, Antoine Chand, Shyam Sahy, Diana Thorsnes, Terje Martma, Tõnu Noble, Stephen R. Pedersen, Jon Halvard Brunstad, Harald Lepland, Aivo |
author_sort |
Crémière, Antoine |
title |
Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea |
title_short |
Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea |
title_full |
Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea |
title_fullStr |
Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea |
title_full_unstemmed |
Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea |
title_sort |
structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the harstad basin, southwest barents sea |
publisher |
Elsevier |
publishDate |
2018 |
url |
https://oceanrep.geomar.de/id/eprint/47187/ https://oceanrep.geomar.de/id/eprint/47187/1/Cremiere.pdf https://doi.org/10.1016/j.marpetgeo.2018.07.010 |
geographic |
Barents Sea |
geographic_facet |
Barents Sea |
genre |
Barents Sea Ice Sheet |
genre_facet |
Barents Sea Ice Sheet |
op_relation |
https://oceanrep.geomar.de/id/eprint/47187/1/Cremiere.pdf Crémière, A. , Chand, S., Sahy, D., Thorsnes, T., Martma, T. , Noble, S. R., Pedersen, J. H., Brunstad, H. and Lepland, A. (2018) Structural controls on seepage of thermogenic and microbial methane since the last glacial maximum in the Harstad Basin, southwest Barents Sea. Marine and Petroleum Geology, 98 . pp. 569-581. DOI 10.1016/j.marpetgeo.2018.07.010 <https://doi.org/10.1016/j.marpetgeo.2018.07.010>. doi:10.1016/j.marpetgeo.2018.07.010 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.marpetgeo.2018.07.010 |
container_title |
Marine and Petroleum Geology |
container_volume |
98 |
container_start_page |
569 |
op_container_end_page |
581 |
_version_ |
1766370144308690944 |