| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Seafloor facies related to upward methane flux within a Giant Pockmark of the Lower Congo Basin
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| Autores: |
Gay, Aurelien
Lopez, M
Ondreas, Helene
Charlou, Jean-luc
Sermondadaz, G
Cochonat, Pierre
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| Data: |
2006-02
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| Ano: |
2006
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| Palavras-chave: |
BIOZAIRE
ZAIANGO
Palaeochannel
Hydrates
Chemosynthesis
Seafloor facies
Fluid migration
Pockmark
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| Resumo: |
The origin of the cold fluid venting from a Giant Pockmark within the Lower Congo Basin has been elucidated based upon results of precise mapping, submersible dives, gravity coring and isotopic analyses realized under a TOTAL-IFREMER cooperative project (ZAIANGO and BIOZAIRE projects). During four dives of the IFREMER ROV-Victor 6000, the bottom was filmed, hard and soft samples were lifted from the sediment, and water samples were collected with a CTD-rosette system. The detailed dip map shows that the 800 in wide Giant Pockmark is a composite feature due to the coalescence of multiple 100 in wide depressions that displays a broad range of biological, mineralogical and chemical features on the seafloor, leading to a seafloor anomaly recorded on the multibeam imagery. Methane-rich fluids migrating through the sedimentary column from a buried palaeochannel clearly react with the sulphate-rich circulating sea water to produce hydrogen sulphide and bicarbonate ions. This situation leads to a concentrical arrangement of the sedimentary facies, with methane-related features in the centre and sulphide-related features at the periphery. This organization is correlated with high levels of methane (up to 20 mu mol/l) measured in the centre of the Giant Pockmark, responsible for the crystallization of gas hydrates at the bottom. In this model, the concentrical organization of mineralogical and biological features reflects a geochemical partitioning related to the peripheral progressive mixing of the methane flux.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
http://archimer.ifremer.fr/doc/2006/publication-1114.pdf
DOI:10.1016/j.margeo.2005.09.011
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| Editor: |
Elsevier
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| Relação: |
http://archimer.ifremer.fr/doc/00000/1114/
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| Formato: |
application/pdf
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| Fonte: |
Marine Geology (0025-3227) (Elsevier), 2006-02 , Vol. 226 , N. 1-2 , P. 81-95
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| Direitos: |
2005 Elsevier B.V. All rights reserved
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