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Registros recuperados: 29
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Analysis of Holocene sedimentary features on the Adriatic shelf from 3D very high resolution seismic data (Triad survey) ArchiMer
Marsset, Tania; Marsset, Bruno; Thomas, Yannick; Cattaneo, Antonio; Thereau, Estelle; Trincardi, F; Cochonat, Pierre.
Very High Resolution (VHR) 3D seismic data were collected on the Adriatic shelf offshore the city of Ortona in order to define the small-scale geometric complexity of late Holocene deposits. Three groups of units are distinguished from the bottom up: (1) units U1 to U3 forming the Transgressive System Tract (TST); (2) units U4 and U5 representing the condensed interval deposited on the Maximum flooding surface (MFS) and the basal unit of the High stand System Tract (HST); and (3) U6 to U 10 forming the progradational units of the HST. The muddy HST deposits show seafloor and subsurface sedimentary features over up to 40% of its extent on the Adriatic shelf. In the area offshore Ortona, the HST shows shore-parallel undulations in water depth of ca. 30-70 m...
Tipo: Text Palavras-chave: Bottom hugging currents; Sediment deformation; 3D VHR seismic; Adriatic shelf; Late Holocene.
Ano: 2004 URL: http://archimer.ifremer.fr/doc/2004/publication-496.pdf
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Inferring denudation variations from the sediment record; an example of the last glacial cycle record of the Golo Basin and watershed, East Corsica, western Mediterranean sea ArchiMer
Calves, Gerome; Toucanne, Samuel; Jouet, Gwenael; Charrier, Simon; Thereau, Estelle; Etoubleau, Joel; Marsset, Tania; Droz, Laurence; Bez, M.; Abreu, V.; Jorry, Stephan; Mulder, T.; Lericolais, Gilles.
Geophysical data and sampling of the Golo Basin (East Corsica margin) provide the opportunity to study mass balance in a single drainage system over the last 130 kyr, by comparing deposited sediments in the sink and the maximum eroded volume in the source using total denudation proxies. Evaluation of the solid sediments deposited offshore and careful integration of uncertainties from the age model and physical properties allow us to constrain three periods of sedimentation during the last climatic cycle. The peak of sedimentation initiated during Marine Isotopic Stage (MIS) 3 (ca. 45 ka) and lasted until late in MIS 2 (ca. 18 ka). This correlates with Mediterranean Sea palaeoclimatic records and the glaciation in high altitude Corsica. The yield of solid...
Tipo: Text
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00087/19779/17480.pdf
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Gas hydrate distributions in sediments of pockmarks from the Nigerian Margin - Results and interpretation from shallow drilling ArchiMer
Wei, Jiangong; Pape, Thomas; Sultan, Nabil; Colliat, Jean-louis; Himmler, Tobias; Ruffine, Livio; De Prunele, Alexis; Dennielou, Bernard; Garziglia, Sebastien; Marsset, Tania; Peters, Carl A.; Rabiu, Abdulkarim; Bohrmann, Gerhard.
A joint research expedition between the French IFREMER and the German MARUM was conducted in 2011 using the R/V Pourquoi pas? to study gas hydrate distributions in a pockmark field (1141 – 1199 meters below sea surface) at the continental margin of Nigeria. The sea floor drill rig MeBo of MARUM was used to recover sediments as deep as 56.74 meters below seafloor. The presence of gas hydrates in specific core sections was deduced from temperature anomalies recorded during continuous records of infrared thermal scanning and anomalies in pore water chloride concentrations. In situ sediment temperature measurements showed elevated geothermal gradients of up to 258 °C/km in the center of the so-called pockmark A which is up to 4.6 times higher than that in the...
Tipo: Text Palavras-chave: Gas hydrate; Pockmark; Chloride profile; Infrared thermal imaging; Fluid flow; Nigerian continental margin; MeBo drill rig.
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00213/32382/30846.pdf
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Sr/Ca and Mg/Ca ratios in Niger Delta sediments: Implications for authigenic carbonate genesis in cold seep environments ArchiMer
Bayon, Germain; Pierre, C; Etoubleau, Joel; Voisset, Michel; Cauquil, E; Marsset, Tania; Sultan, Nabil; Le Drezen, Eliane; Fouquet, Yves.
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,...
Tipo: Text Palavras-chave: Niger Delta; Gas hydrates; Cold seeps; Mg/Ca; Sr/Ca; Authigenic carbonates.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-2696.pdf
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Organic carbon accumulation in modern sediments of the Angola basin influenced by the Congo deep sea fan ArchiMer
Baudin, Francois; Martinez, Philippe; Dennielou, Bernard; Charlier, Karine; Marsset, Tania; Droz, Laurence; Rabouille, Christophe.
Geochemical data (total organic carbon-TOC content, δ13Corg, C:N, Rock-Eval analyses) were obtained on 150 core tops from the Angola basin, with a special focus on the Congo deep sea fan. Combined with the previously published data, the resulting dataset (322 stations) shows a good spatial and bathymetric representativeness. TOC content and δ13Corg maps of the Angola basin were generated using this enhanced dataset. The main difference in our map with previously published ones is the high terrestrial organic matter content observed downslope along the active turbidite channel of the Congo deep sea fan till the distal lobe complex near 5,000 m of water-depth. Interpretation of downslope trends in TOC content and organic matter composition indicates that...
Tipo: Text Palavras-chave: Organic matter; Recent sediments; South Atlantic Ocean; Turbidites.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00369/47974/47999.pdf
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Potential role of compressional structures in generating submarine slope failures in the Niger Delta ArchiMer
Sultan, Nabil; Voisset, Michel; Marsset, Bruno; Marsset, Tania; Cauquil, E; Colliat, J.
The study area, offshore Nigeria, is located in one of the compressional zones within the Niger Delta, which is characterized by imbricate thrust structures. Although the low mean slope angle (around 2°), bathymetry data from the study area have shown the existence of several submarine landslides which coincide with known subsurface faulted compressive features. In this paper, we have focused on a submarine slide occurring in water depths ranging between 1690 and 1750 m. Headwall scars, internal architecture and associated deposits have been characterized using a combination of 3D seismic data, near-bottom echosounder seismic profiles, Kullenberg cores and in-situ geotechnical measurements. The slide shows horseshoe shaped headwall scars and depositional...
Tipo: Text Palavras-chave: Slope stability; Piezometer; Penetrometer; Niger Delta; Modelling; Compressional structures.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-2408.pdf
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SYSIF, a low frequency seismic profiler for near-bottom marine geophysics ArchiMer
Ker, Stephan; Le Gall, Yves; Marsset, Tania; Leon, Pierre.
Ifremer has recently developed a deep-towed seismic system designed for High to Very High resolution near-bottom marine seismic surveys. This paper presents this new tool which is dedicated to the study of deepwater geological objects especially geohazards. After a technical description of the system, we expound an overview of the complete workflow from survey design to amplitude preserved processing illustrated by data acquired during sea trials.
Tipo: Text
Ano: 2008 URL: http://archimer.ifremer.fr/doc/00127/23841/21767.pdf
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Origin of an enigmatic regional Mio-Pliocene unconformity on the Demerara plateau ArchiMer
Pattier, France; Loncke, L.; Imbert, Patrice; Gaullier, V.; Basile, C.; Maillard, Alexandre; Roest, Walter; Patriat, Martin; Vendeville, B. C.; Marsset, Tania; Bayon, Germain; Cathalot, Cecile; Caprais, Jean-claude; Bermell, Sylvain; Sotin, Christine; Hebert, Bertil; Mercier De Lepinay, Marion; Lebrun, J. F.; Marcaillou, B.; Heuret, A.; Droz, Laurence; Graindorge, David; Poetisi, E.; Berrenstein, H..
The Demerara plateau, located offshore French Guiana and Suriname, is part of a passive transform continental margin particularly prone to develop slope instabilities, probably in relation to the presence of a free distal border along its steep continental slope. Slope failure occurred at different periods (Cretaceous to Neogene) and shows an overall retrogressive evolution through time. Upslope these failure headscarp, an enigmatic regional MioPliocene unconformity has been discovered through the interpretation of new academic and industrial datasets. The aim of this work is to describe and understand the origin of this surface. Our analysis shows that this unconformity is made of a series of valleys that cross-cut sedimentary strata. Each one of these...
Tipo: Text Palavras-chave: Unconformity; Hydrate pockmark; Slide; Contourite; Valley; Canyon; Demerara plateau.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00271/38193/36735.pdf
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Types of fluid-related features controlled by sedimentary cycles and fault network in deepwater Nigeria ArchiMer
Marsset, Tania; Ruffine, Livio; Ker, Stephan; Cauquil, E.; Gay, Aurelien.
The seismic characteristics of focused fluid-related features such as pockmarks and carbonate build-ups on the Nigerian continental slope have been investigated using complementary seismic data sets (reprocessed 3D exploration data and 2D Very High Resolution hull-mounted and near-bottom seismic data) coupled with the results of previous studies (sedimentological, geotechnical and geochemical analyses). The results show different types of fluid-related features within the hemipelagic phase of long duration (∼1 Myr) Turbidite/Hemipelagic cycles. They are the product of the disturbance of the hosting sediments following two main distinct processes: (1) no or low sediment deposition caused by fluid escape associated with seafloor settlement (benthic fauna,...
Tipo: Text Palavras-chave: Niger delta; Fluid flow; Pockmark; Gas hydrates; Methane-derived carbonate; Fault network; Sedimentary cycles.
Ano: 2018 URL: http://archimer.ifremer.fr/doc/00405/51650/52199.pdf
Registros recuperados: 29
Primeira ... 12 ... Última
 

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