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| Tallobre, Cedric; Loncke, Lies; Bassetti, Maria-angela; Giresse, Pierre; Bayon, Germain; Buscail, Roselyne; De Madron, Xavier Durrieu; Bourrin, Francois; Vanhaesebroucke, Marc; Sotin, Christine. |
| The Demerara Plateau, belonging to the passive transform margin of French Guiana, was investigated during the IGUANES cruise in 2013. The objectives of the cruise were to explore the poorly-known surficial sedimentary column overlying thick mass transport deposits as well as to understand the factors controlling recent sedimentation. The presence of numerous bedforms at the seafloor was observed thanks to newly acquired IGUANES bathymetric, high resolution seismic and chirp data, while sediment cores allowed the characterization of the deposits covering the mass transport deposits. Modern oceanographic conditions were determined in situ, using mooring monitoring over a 10-month period. Our data indicate the presence of a Contourite Depositional System... |
| Tipo: Text |
Palavras-chave: Marginal plateau; Contourite; Comet tail; Demerara Plateau. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00308/41957/41220.pdf |
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| Tallobre, Cédric; Giresse, Pierre; Bassetti, Maria-angela; Loncke, Lies; Bayon, Germain; Buscail, Roselyne; Tudryn, Alina; Zaragosi, Sébastien. |
| The Demerara Plateau is a marginal plateau which forms a bathymetric relief on the sea floor. Here, contourite deposits have been studied in detail, following the recent discovery of contourite sequences likely related to the bottom currents and linked both to contour current and peculiar sea-floor morphology. A chronostratigraphic framework, based on δ18O relative variations and palaeomagnetic events in sediment cores allows correlating sediment processes to current intensity changes and major climate phases (glacial or interglacial). The studied sediments are enriched in glauconitic grains. In addition, the glauconite mineralogical maturity can easily correlate to low sedimentation rate and slightly energetic bottom currents on the seafloor. Based on... |
| Tipo: Text |
Palavras-chave: Marginal plateau; Contourite; Glauconite; Demerara plateau. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00485/59665/62724.pdf |
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| Giresse, Pierre; Bayon, Germain; Tallobre, Cédric; Loncke, Lies. |
| Contourite sediment accumulations at continental margins are related to strong bottom water circulation, where intense winnowing can result in neoformation of authigenic grains of glauconite at the seafloor. In this study, we investigated whether such glauconite grains could faithfully record ambient bottom-water neodymium (Nd) isotopic compositions, and hence be used as paleoceanographic archives. To this purpose, we measured Nd isotopic compositions (εNd) in a series of glauconitic grains, foraminiferal assemblages, leached Fe-Mn oxyhydroxide phases, and detrital clays separated from a contourite sediment record at the Demerara slope off French Guiana (IG-KSF-11; 2370 m water depth), at a location where the present-day εNd distribution along the water... |
| Tipo: Text |
Palavras-chave: Rare earth elements; Neodymium isotopes; Glauconitisation; Demerara; Contourite. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00689/80085/83115.pdf |
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| Dennielou, Bernard; Jallet, Laurent; Sultan, Nabil; Jouet, Gwenael; Giresse, Pierre; Voisset, Michel; Berne, Serge. |
| Emplacement of post-glacial turbidites is commonly controlled by rapid changes in sea level or by seismicity. On the continental rise of the Gulf of Lions (Western Mediterranean), an aseismic area, we identified turbiditic beds deposited during the rising stage and highstand of sea level. Swath bathymetry, sediment cores, in situ Cone Penetrating Tests (CPTU), heavy mineral associations and radiocarbon dating determined the source, composition, distribution and age of the turbiditic beds. Turbidites are composed of homogeneous to positively graded silts to medium sand with quartz (up to 90%), shell debris and shelfal benthic faunas. Their distribution on the sea floor is very patchy and controlled by abundant inherited erosional bedforms. Their source is... |
| Tipo: Text |
Palavras-chave: Holocene; Late Pleistocene; Sea level; Turbidites; Sand; Outer shelf; Canyons. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6316.pdf |
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| Giresse, Pierre. |
| The comments on the photographs that we present here constitute a follow up to the article "Photographie sous-marine et géologie" (submarine photography and geology) (L. DANGEARD and P. GIRESSE, 1965). They deal with the sedimentary structures - of animal origin for most of them - found in the submerged areas of the fluviomarine ecosystem and that can be compared to those of the continental shelf and great depths. |
| Tipo: Text |
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| Ano: 1966 |
URL: http://archimer.ifremer.fr/doc/1966/publication-3980.pdf |
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