Data/hora: 08/06/2024 10:38:28

Provedor de dados: | 5
País: | France
Título: | Evidence of paleo-cold seep activity from the Bay of Bengal, offshore India
Autores: | Mazumdar, A.; Dewangan, P.; Joaeo, H. M.; Peketi, A.; Khosla, V. R.; Kocherla, M.; Badesab, F. K.; Joshi, R. K.; Roxanne, P.; Ramamurty, P. B.; Karisiddaiah, S. M.; Patil, D. J.; Dayal, A. M.; Ramprasad, T.; Hawkesworth, C. J.; Avanzinelli, R.
Data: | 2009-06-12
Ano: | 2009
Palavras-chave: | Methane hydrate; Cold seep; Authigenic carbonate; Bay of Bengal; AMO; Chemosynthetic community.
Resumo: | We report evidence of paleo-cold seep associated activities, preserved in methane-derived carbonates in association with chemosynthetic clams (Calyptogena sp.) from a sediment core in the Krishna-Godavari basin, Bay of Bengal. Visual observations and calculations based on high-resolution wet bulk density profile of a core collected on board R/V Marion Dufresne (May 2007) show zones of sharp increase in carbonate content (10-55 vol%) within 16-20 meters below seafloor (mbsf). The presence of Calyptogena clam shells, chimneys, shell breccias with high Mg calcite cement, and pyrite within this zone suggest seepage of methane and sulfide-bearing fluid to the seafloor in the past. Highly depleted carbon isotopic values (delta(13)C ranges from -41 to -52% VPDB) from these carbonates indicate carbon derived via anaerobic oxidation of methane. Extrapolated mean calendar age (similar to 58.7 ka B. P.) of the clastic sediments at a depth of 16 mbsf is close to the upper limit of the U-Th based depositional age (46.2 +/- 3.7 and 53.0 +/- 1.6 ka) of authigenic carbonates sampled from this level, thereby constraining the younger age limit of the carbonate deposition/methane expulsion events. The observed carbonate deposition might have resulted from the flow of methane-enriched fluids through the fracture network formed because of shale diapirism.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00218/32911/31414.pdf

DOI:10.1029/2008GC002337

https://archimer.ifremer.fr/doc/00218/32911/

Editor: | Amer Geophysical Union
Formato: | application/pdf
Fonte: | Geochemistry Geophysics Geosystems (1525-2027) (Amer Geophysical Union), 2009-06-12 , Vol. 10 , N. 6 , P. 1-15

Fonte:

Copyright 2009 by the American Geophysical Union

info:eu-repo/semantics/openAccess

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