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Ruffine, Livio; Caprais, Jean-claude; Bayon, Germain; Riboulot, Vincent; Donval, Jean-pierre; Etoubleau, Joel; Birot, Dominique; Pignet, Patricia; Rongemaille, Emmanuelle; Chazallon, Bertrand; Grimaud, Sylvie; Adamy, Jerome; Charlou, Jean-luc; Voisset, Michel. |
A joint industrial project with IFREMER and Total provides insights into the tectonic setting and the geochemistry of a large active pockmark offshore W-Africa in the Niger Delta. The study combines both geophysical (seismic) and geochemical data to infer the dynamics of a 300 m wide pockmark located at 667 m water depth. Two Calypso cores, one at the centre and one outside the pockmark, along with three box-cores, two inside the pockmark and one outside, were collected to study the geochemistry of gas hydrates, carbonates and pore waters. Two seismic lines, a 3D high resolution random line and a 2D high resolution seismic line, provide a good description of the plumbing of the system. The integrated results depict a very active pockmark characterized by... |
Tipo: Text |
Palavras-chave: Active pockmark; Anaerobic oxidation of methane; Gas hydrates; Carbonates; Seismic surveys; Fault system; U/Th dating. |
Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00139/24981/23102.pdf |
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Gay, Aurelien; Lopez, M; Cochonat, Pierre; Sermondadaz, G. |
A new polygonal fault system has been identified in the Lower Congo Basin. This highly faulted interval (HFI), 700+/-50 m thick, is characterized by small extensional faults displaying a polygonal pattern in plan view. This kind of fracturing is attributed to volumetric contraction of sediments during early stages of compaction at shallow burial depth. 3-D seismic data permitted the visualization of the progressive deformation of furrows during burial, leading to real fractures, visible on seismic sections at about 78 m below seafloor. We propose a new geometrical model for volumetrical contraction of mud-dominated sediments. Compaction starts at the water-sediment interface by horizontal contraction, creating furrows perpendicular to the present day... |
Tipo: Text |
Palavras-chave: Water sediment interface; Seafloor; Sedimentary basin; Geometrical model; Furrow; Fault system. |
Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-1115.pdf |
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