Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin
International audience Gas hydrate provinces occur in two sedimentary basins along Brazil’s continental margin: (1) The Rio Grande Cone in the southeast, and (2) the Amazon deep-sea fan in the equatorial region. The occurrence of gas hydrates in these depocenters was first detected geophysically and...
Published in: | Geosciences |
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Main Authors: | , , , , , , |
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Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2019
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Online Access: | https://hal.archives-ouvertes.fr/hal-02187854 https://hal.archives-ouvertes.fr/hal-02187854/document https://hal.archives-ouvertes.fr/hal-02187854/file/Ketzer%26al_Geosciences_2019.pdf https://doi.org/10.3390/geosciences9050193 |
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English |
topic |
ocean acidification gas hydrates gas seeps [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
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ocean acidification gas hydrates gas seeps [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Ketzer, Marcelo Praeg, Daniel Pivel, Maria A.G. Augustin, Adolpho, Rodrigues, Luiz, Viana, Adriano Cupertino, José Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin |
topic_facet |
ocean acidification gas hydrates gas seeps [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience Gas hydrate provinces occur in two sedimentary basins along Brazil’s continental margin: (1) The Rio Grande Cone in the southeast, and (2) the Amazon deep-sea fan in the equatorial region. The occurrence of gas hydrates in these depocenters was first detected geophysically and has recently been proven by seafloor sampling of gas vents, detected as water column acoustic anomalies rising from seafloor depressions (pockmarks) and/or mounds, many associated with seafloor faults formed by the gravitational collapse of both depocenters. The gas vents include typical features of cold seep systems, including shallow sulphate reduction depths (<4 m), authigenic carbonate pavements, and chemosynthetic ecosystems. In both areas, gas sampled in hydrate and in sediments is dominantly formed by biogenic methane. Calculation of the methane hydrate stability zone for water temperatures in the two areas shows that gas vents occur along its feather edge (water depths between 510 and 760 m in the Rio Grande Cone and between 500 and 670 m in the Amazon deep-sea fan), but also in deeper waters within the stability zone. Gas venting along the feather edge of the stability zone could reflect gas hydrate dissociation and release to the oceans, as inferred on other continental margins, or upward fluid flow through the stability zone facilitated by tectonic structures recording the gravitational collapse of both depocenters. The potential quantity of venting gas on the Brazilian margin under different scenarios of natural or anthropogenic change requires further investigation. The studied areas provide natural laboratories where these critical processes can be analyzed and quantified |
author2 |
Department of Biology and Environmental Science, Linnaeus University Pontifícia Universidade Católica do Rio Grande do Sul Porto Alegre (PUCRS) Géoazur (GEOAZUR 7329) Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD France-Sud )-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA) Departamento de Geologia, LAGEMAR Universidade Federal Fluminense Rio de Janeiro (UFF) Centro de Estudos de Geologia Costeira e Oceânica Petrobras EGP-EXP European Project: 656821,H2020,H2020-MSCA-IF-2014,SEAGAS(2016) |
format |
Article in Journal/Newspaper |
author |
Ketzer, Marcelo Praeg, Daniel Pivel, Maria A.G. Augustin, Adolpho, Rodrigues, Luiz, Viana, Adriano Cupertino, José |
author_facet |
Ketzer, Marcelo Praeg, Daniel Pivel, Maria A.G. Augustin, Adolpho, Rodrigues, Luiz, Viana, Adriano Cupertino, José |
author_sort |
Ketzer, Marcelo |
title |
Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin |
title_short |
Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin |
title_full |
Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin |
title_fullStr |
Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin |
title_full_unstemmed |
Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin |
title_sort |
gas seeps at the edge of the gas hydrate stability zone on brazil’s continental margin |
publisher |
HAL CCSD |
publishDate |
2019 |
url |
https://hal.archives-ouvertes.fr/hal-02187854 https://hal.archives-ouvertes.fr/hal-02187854/document https://hal.archives-ouvertes.fr/hal-02187854/file/Ketzer%26al_Geosciences_2019.pdf https://doi.org/10.3390/geosciences9050193 |
genre |
Methane hydrate Ocean acidification |
genre_facet |
Methane hydrate Ocean acidification |
op_source |
ISSN: 2076-3263 Geosciences https://hal.archives-ouvertes.fr/hal-02187854 Geosciences, MDPI, 2019, 9 (5), pp.193. ⟨10.3390/geosciences9050193⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.3390/geosciences9050193 info:eu-repo/grantAgreement//656821/EU/Multi-disciplinary Comparison of Fluid Venting from Gas Hydrate Systems on the Mediterranean and Brazilian Continental Margins over Glacial-Interglacial Timescales/SEAGAS hal-02187854 https://hal.archives-ouvertes.fr/hal-02187854 https://hal.archives-ouvertes.fr/hal-02187854/document https://hal.archives-ouvertes.fr/hal-02187854/file/Ketzer%26al_Geosciences_2019.pdf doi:10.3390/geosciences9050193 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.3390/geosciences9050193 |
container_title |
Geosciences |
container_volume |
9 |
container_issue |
5 |
container_start_page |
193 |
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1766068914076254208 |
spelling |
ftccsdartic:oai:HAL:hal-02187854v1 2023-05-15T17:12:08+02:00 Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin Ketzer, Marcelo Praeg, Daniel Pivel, Maria A.G. Augustin, Adolpho, Rodrigues, Luiz, Viana, Adriano Cupertino, José Department of Biology and Environmental Science, Linnaeus University Pontifícia Universidade Católica do Rio Grande do Sul Porto Alegre (PUCRS) Géoazur (GEOAZUR 7329) Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD France-Sud )-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA) Departamento de Geologia, LAGEMAR Universidade Federal Fluminense Rio de Janeiro (UFF) Centro de Estudos de Geologia Costeira e Oceânica Petrobras EGP-EXP European Project: 656821,H2020,H2020-MSCA-IF-2014,SEAGAS(2016) 2019-05 https://hal.archives-ouvertes.fr/hal-02187854 https://hal.archives-ouvertes.fr/hal-02187854/document https://hal.archives-ouvertes.fr/hal-02187854/file/Ketzer%26al_Geosciences_2019.pdf https://doi.org/10.3390/geosciences9050193 en eng HAL CCSD MDPI info:eu-repo/semantics/altIdentifier/doi/10.3390/geosciences9050193 info:eu-repo/grantAgreement//656821/EU/Multi-disciplinary Comparison of Fluid Venting from Gas Hydrate Systems on the Mediterranean and Brazilian Continental Margins over Glacial-Interglacial Timescales/SEAGAS hal-02187854 https://hal.archives-ouvertes.fr/hal-02187854 https://hal.archives-ouvertes.fr/hal-02187854/document https://hal.archives-ouvertes.fr/hal-02187854/file/Ketzer%26al_Geosciences_2019.pdf doi:10.3390/geosciences9050193 info:eu-repo/semantics/OpenAccess ISSN: 2076-3263 Geosciences https://hal.archives-ouvertes.fr/hal-02187854 Geosciences, MDPI, 2019, 9 (5), pp.193. ⟨10.3390/geosciences9050193⟩ ocean acidification gas hydrates gas seeps [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2019 ftccsdartic https://doi.org/10.3390/geosciences9050193 2021-12-12T01:12:45Z International audience Gas hydrate provinces occur in two sedimentary basins along Brazil’s continental margin: (1) The Rio Grande Cone in the southeast, and (2) the Amazon deep-sea fan in the equatorial region. The occurrence of gas hydrates in these depocenters was first detected geophysically and has recently been proven by seafloor sampling of gas vents, detected as water column acoustic anomalies rising from seafloor depressions (pockmarks) and/or mounds, many associated with seafloor faults formed by the gravitational collapse of both depocenters. The gas vents include typical features of cold seep systems, including shallow sulphate reduction depths (<4 m), authigenic carbonate pavements, and chemosynthetic ecosystems. In both areas, gas sampled in hydrate and in sediments is dominantly formed by biogenic methane. Calculation of the methane hydrate stability zone for water temperatures in the two areas shows that gas vents occur along its feather edge (water depths between 510 and 760 m in the Rio Grande Cone and between 500 and 670 m in the Amazon deep-sea fan), but also in deeper waters within the stability zone. Gas venting along the feather edge of the stability zone could reflect gas hydrate dissociation and release to the oceans, as inferred on other continental margins, or upward fluid flow through the stability zone facilitated by tectonic structures recording the gravitational collapse of both depocenters. The potential quantity of venting gas on the Brazilian margin under different scenarios of natural or anthropogenic change requires further investigation. The studied areas provide natural laboratories where these critical processes can be analyzed and quantified Article in Journal/Newspaper Methane hydrate Ocean acidification Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Geosciences 9 5 193 |