| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Sr/Ca and Mg/Ca ratios in Niger Delta sediments: Implications for authigenic carbonate genesis in cold seep environments
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| Autores: |
Bayon, Germain
Pierre, C
Etoubleau, Joel
Voisset, Michel
Cauquil, E
Marsset, Tania
Sultan, Nabil
Le Drezen, Eliane
Fouquet, Yves
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| Data: |
2007-06
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| Ano: |
2007
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| Palavras-chave: |
Niger Delta
Gas hydrates
Cold seeps
Mg/Ca
Sr/Ca
Authigenic carbonates
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| Resumo: |
We report on a reconnaissance analysis of the geochemical composition of authigenic carbonates and sediment samples collected from various seepage sites on the Niger deep-sea fan. Our aim has been to investigate whether evidence for the presence of authigenic carbonates and gas hydrates within sediments is discernible from solid-phase sediment geochemistry. We show that sedimentary Sr/Ca and Mg/Ca ratios can be used to infer the presence of authigenic aragonite (Sr-rich) and Mg-rich carbonate phases (high-Mg calcite, dolomite) in cold seep settings. Using Sr/Ca and Mg/Ca ratios, the proportion (wt.%) of authigenic carbonates in Niger Fan sediments can be calculated from a mixing model between sediment fractions of terrigenous material, biogenic calcite, aragonite and high-Mg calcite. This approach was applied to high-resolution geochemical profiles along sediment cores recovered from various cold seep settings (mud volcano, diapirs, pockmarks, gas-hydrate bearing sediments). Our data reveal that authigenic carbonates occur as discrete phases in sediments from gas-hydrate-bearing areas, suggesting that such carbonate-rich sediment layers may represent paleo-indicators for ancient methane seepage in marine sediments, possibly associated to gas-hydrate reservoirs. (C) 2007 Elsevier B.V. All rights reserved.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
http://archimer.ifremer.fr/doc/2007/publication-2696.pdf
DOI:10.1016/j.margeo.2007.03.007
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| Editor: |
Elsevier
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| Relação: |
http://archimer.ifremer.fr/doc/00000/2696/
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| Formato: |
application/pdf
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| Fonte: |
Marine Geology (0025-3227) (Elsevier), 2007-06 , Vol. 241 , N. 1-4 , P. 93-109
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| Direitos: |
2007 Elsevier B.V. All rights reserved
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