|
|
|
| Registros recuperados: 29 | |
|
| |
|
|
| Sultan, Nabil; Bohrmann, G.; Ruffine, Livio; Pape, T.; Riboulot, Vincent; Colliat, J. -l.; De Prunele, Alexis; Dennielou, Bernard; Garziglia, Sebastien; Himmler, Tobias; Marsset, Tania; Peters, C. A.; Rabiu, A.; Wei, J.. |
| In previous works, it has been suggested that dissolution of gas hydrate can be responsible for pockmark formation and evolution in deep water Nigeria. It was shown that those pockmarks which are at different stages of maturation are characterized by a common internal architecture associated to gas hydrate dynamics. New results obtained by drilling into gas hydrate-bearing sediments with the MeBo seafloor drill rig in concert with geotechnical in situ measurements and pore water analyses indicate that pockmark formation and evolution in the study area are mainly controlled by rapid hydrate growth opposed to slow hydrate dissolution. On one hand, positive temperature anomalies, free gas trapped in shallow microfractures near the seafloor and coexistence of... |
| Tipo: Text |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29913/28373.pdf |
| |
|
| |
|
|
| Palm, Franziska A.; Peakall, Jeff; Hodgson, David M.; Marsset, Tania; Silva Jacinto, Ricardo; Dennielou, Bernard; Babonneau, Nathalie; Wright, Tim J.. |
| Submarine-fan channels can build the largest sediment accumulations on Earth, but our understanding of flow and sedimentation processes related to channel evolution remains limited. Results from physical and numerical modelling predict dominantly downstream channel bend migration. However, observations and evolutionary models for aggradational submarine channels on passive margins suggest that bends are dominated by lateral expansion. This paradox may be due to limitations induced by the use of constant width channels in process studies. Constant width has been used for two reasons: partly because this is the simplest possible case, but primarily because the width variation around submarine channel bends is unknown. Channel width variations are examined... |
| Tipo: Text |
Palavras-chave: Submarine channel; Congo; Channel morphology; Sedimentation; Bank pull; Quaternary; Monsoon; South Atlantic. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00693/80473/83602.pdf |
| |
|
| |
|
|
| Dalibard, Mathieu; Popescu, Speranta-maria; Maley, Jean; Baudin, Francois; Melinte-dobrinescu, Mihaela-carmen; Pittet, Bernard; Marsset, Tania; Dennielou, Bernard; Droz, Laurence; Suc, Jean-pierre. |
| The essential characteristics of the vegetation dynamics of tropical Africa remain only partially known. This study assesses the succession of vegetation-types over Central Africa during the last two glacial/interglacial cycles. Analysis of core KZai 02, which contains pollen from the Zaire River watershed (latitudes 9°N-13°S), allows the investigation of long-term patterns of plant ecosystem development and their climatic causes. Core KZai 02 (18.20 m long) was recovered from 6°24.20′S/9°54.10′E in the uppermost axial edifice of the Zaire deep sea fan. The chronology of this sedimentary archive was established using nannofossils and correlations of pollen and total organic carbon signals with the nearby core GeoB1008. The pollen record indicates that: (i)... |
| Tipo: Text |
Palavras-chave: Central Africa; Climate; Environmental parameters; Late Pleistocene; Pollen; Vegetation dynamics. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00199/31031/29436.pdf |
| |
|
|
| Hardy, William; Penaud, Aurelie; Marret, Fabienne; Bayon, Germain; Marsset, Tania; Droz, Laurence. |
| A new 44 kyr long record of dinoflagellate (phytoplanktonic organisms) cysts (dinocysts) is presented from a marine sediment core collected on the Congolese margin with the aim of reconstructing past hydrological changes in the equatorial eastern Atlantic Ocean since Marine Isotopic Stage (MIS) 3. Our high-resolution dinocyst record indicates that significant temperature and moisture variations occurred across the glacial period, the last deglaciation and the Holocene. The use of specific dinocyst taxa, indicative of fluvial, upwelling and Benguela Current past environments for instance, provides insights into the main forcing mechanisms controlling palaeohydrological changes on orbital timescales. In particular, we are able, for the last 44 kyr, to... |
| Tipo: Text |
|
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00349/46006/45675.pdf |
| |
|
|
| Hatin, T.; Crosta, X.; Le Herisse, A.; Droz, L.; Marsset, Tania. |
| Changes in siliceous productivity in the eastern Equatorial Atlantic Ocean, off the Western African margin, over the last several glacial cycles have been either related to global-to-regional oceanographic changes (upwelling intensity) or climate changes (precipitation and river discharge). Based on diatom assemblages in core KZAI-02, located to the south of the mouth of the Congo River, integrated with a selection of geochemical proxies, we show that siliceous productivity in the southeastern Angola Basin responded to non-linear interactions between both oceanographic and climate changes over the last 190,000 years. High diatom accumulation rates were recorded in the middle part of MIS 6, in cold substage MIS 5d and in MIS 3-2. During these intervals,... |
| Tipo: Text |
Palavras-chave: Diatoms; Productivity; Late quaternary; Millennial time scale; Congo fan area. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00363/47402/47394.pdf |
| |
|
| |
|
|
| Fanget, Anne-sophie; Loncke, Lies; Pattier, France; Marsset, Tania; Roest, Walter; Tallobre, Cédric; Durrieu De Madron, Xavier; Hernandez Molina, F. Javier. |
| The Demerara Plateau, off the French Guiana and Surinam margin, corresponds to a prominent sub-horizontal marginal plateau. The interpretation of a large set of seismic data acquired along the Demerara Plateau and integration with previous seismic stratigraphy and drill studies enables a better understanding of the sedimentary evolution of the outer Demerara marginal plateau. Since the end of the transform activity (late Albian), three sedimentary evolutionary stages have been identified. 1) The Pre-contourite Stage (late Albian to early Miocene) is strongly controlled by the structure of the margin that influences the distribution pattern of post-transform deposits through differential thermal subsidence between transform and divergent segments. 2) The... |
| Tipo: Text |
Palavras-chave: Marginal plateau; Demerara Plateau; Contourite; Bottom currents; Mass transport deposits; Atlantic Ocean. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00599/71125/69439.pdf |
| |
|
|
| Sweet, Michael L.; Gaillot, Gwladys T.; Jouet, Gwenael; Rittenour, Tammy M.; Toucanne, Samuel; Marsset, Tania; Blum, Michael D.. |
| How and when sediment moves from shallow marine to deep-water environments is an important and poorly understood control on basin-scale sediment dispersal patterns, the evolution of continental margins, and hydrocarbon exploration in deep-water basins. The Golo River (Eastern Corsica, France), its delta, canyons, and fans provide a unique opportunity to study sediment routing from source to sink in a relatively compact depositional system. We studied this system using an array of high-frequency seismic data, multi-beam bathymetry, and five cores for lithology and age control. Movement of sediment to deep water was controlled by interactions between the Golo River, the Golo Delta, and shelf-penetrating submarine canyons. Sediment moved to deep water when... |
| Tipo: Text |
|
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00589/70154/68234.pdf |
| |
|
|
| Riboulot, Vincent; Cattaneo, Antonio; Scalabrin, Carla; Gaillot, Arnaud; Jouet, Gwenael; Ballas, Gregory; Marsset, Tania; Garziglia, Sebastien; Ker, Stephan. |
| The Romanian sector of the Black Sea deserves attention because the Danube deep-sea fan is one of the largest sediment depositional systems worldwide and is considered the world's most isolated sea, the largest anoxic water body on the planet and a unique energy-rich sea. Due to the high sediment accumulation rate, presence of organic matter and anoxic conditions, the Black sea sediments offshore the Danube delta is rich in gas and thus shows Bottom Simulating Reflectors (BSR). The cartography of the BSR over the last 20 years, exhibits its widespread occurrence, indicative of extensive development of hydrate accumulations and a huge gas hydrate potential. By combining old and new datasets acquired in 2015 during the GHASS expedition, we performed a... |
| Tipo: Text |
Palavras-chave: Hydrates de gaz; Gaz libre; Panaches de gaz; BSR; Mer Noire; Géomorphologie; Gas hydrates; Free gas; Gas flares; BSR; Black Sea; Geomorphology. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00407/51860/53914.pdf |
| |
|
|
| Marsset, Tania; Xia, D; Berne, Serge; Liu, Z; Bourillet, Jean-francois; Wang, K. |
| The Bohai Sea is a shallow sea at the east coast of China. It communicates with the Yellow Sea through a narrow strait. During and since the Late Pleistocene, the Bohai Sea has been a filled subsiding basin submitted to successive regressive-transgressive cycles. In the East Bohai Sea, a number of finger-shaped ridges are present near the strait, where tidal currents are dominant. Very-high resolution seismic reflection data have been interpreted relative to sedimentological data provided by a formerly drilled borehole. Seven seismic units are identified and correlated with the following events: units U7-U6 with the Bohai relative sea level rise (65,000–53,000 yr B.P.) and a relative sea level fall (53,000–39,000 yr B.P.); unit U5 with the Xianxian... |
| Tipo: Text |
Palavras-chave: Eastern Bohai Sea; Late Pleistocene; Stratigraphy; Relative sea level variations; Tidal ridges; Very-high resolution seismic. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00061/17193/14695.pdf |
| |
|
|
| De Prunele, Alexis; Ruffine, Livio; Riboulot, Vincent; Peters, Carl A.; Croguennec, Claire; Guyader, Vivien; Pape, Thomas; Bollinger, Claire; Bayon, Germain; Caprais, Jean-claude; Germain, Yoan; Donval, Jean-pierre; Marsset, Tania; Bohrmann, Gerhard; Geli, Louis; Rabiu, Abdulkarim; Lescanne, Marc; Cauquil, Eric; Sultan, Nabil. |
| The Niger Delta is one of the largest hydrocarbon basin offshore Africa and it is well known for the presence of active pockmarks on the seabed. During the Guineco-MeBo cruise in 2011, long cores were taken from a pockmark cluster in order to investigate the state of its current activity. Gas hydrates, oil and pore-water were sampled for geochemical studies. The resulting dataset combined with seismic data reveal that shallow hydrocarbon migration in the upper sedimentary section was focused exclusively within the pockmarks. There is a clear tendency for gas migration within the hydrate-bearing pockmarks, and oil migration within the carbonate-rich one. This trend is interpreted as a consequence of hydrate dissolution followed by carbonate precipitation... |
| Tipo: Text |
Palavras-chave: Anaerobic oxidation of methane; Cluster of pockmarks; Fluid flow; Gas hydrates; Pore-water profiles; Transient state. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00365/47647/47676.pdf |
| |
|
|
| Sultan, Nabil; Marsset, Bruno; Ker, Stephan; Marsset, Tania; Voisset, Michel; Vernant, Antoine-mathieu; Bayon, Germain; Cauquil, Eric; Adamy, J.; Colliat, J. L.; Drapeau, D.. |
| Based on acquired geophysical, geological and geotechnical data and modeling, we suggest hydrate dissolution to cause sediment collapse and pockmark formation in the Niger delta. Very high-resolution bathymetry data acquired from the Niger delta reveal the morphology of pockmarks with different shapes and sizes going from a small ring depression surrounding an irregular floor to more typical pockmarks with uniform depression. Geophysical data, in situ piezocone measurements, piezometer measurements and sediment cores demonstrate the presence of a common internal architecture of the studied pockmarks: inner sediments rich in gas hydrates surrounded by overpressured sediments. The temperature, pressure and salinity conditions of the studied area have allowed... |
| Tipo: Text |
Palavras-chave: Methane gas hydrate; Sea floor; Marine sediments; Pore pressure; Porous media; Continental margin; Clathrate hydrate; Fluid flow; Stability; Slope. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00012/12300/9092.pdf |
| |
|
| |
|
| |
|
|
| Ballas, Gregory; Garziglia, Sebastien; Sultan, Nabil; Pelleter, Ewan; Toucanne, Samuel; Marsset, Tania; Riboulot, Vincent; Ker, Stephan. |
| The geotechnical properties of clay sediments were investigated using laboratory and in-situ measurements as part of the geohazard assessment in the Romanian sector of the Black Sea affected by landslides and seafloor deformation features. The sediments were characterized as predominantly high plastic silty clay of high compressibility, low undrained shear strength, low cohesion and moderate sensitivity. A shallow increase in shear strength exceeding the general trend could have been reconciled with evidence for the precipitation of iron sulfides and calcium carbonates related to early diagenetic reactions of sulfate reduction (e.g. cryptic sulfur cycle) and anaerobic oxidation of methane. Comparison of the compression behaviour of natural and... |
| Tipo: Text |
Palavras-chave: Lacustrine clay sediment; Structured material; Sulfur cement; Carbonate cement; Early diagenesis; Weak layer. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00439/55064/56545.pdf |
| |
|
|
| Bayon, Germain; Henderson, Gideon M.; Etoubleau, Joel; Caprais, Jean-claude; Ruffine, Livio; Marsset, Tania; Dennielou, Bernard; Cauquil, Eric; Voisset, Michel; Sultan, Nabil. |
| The application of uranium-thorium dating methods to authigenic carbonates provides unique constraints on the temporal evolution of methane seeps at ocean margins. In this study, we report U-Th isotope measurements for carbonate breccias collected from within a hydrate-bearing pockmark located at the Niger Delta margin. These concretions were extracted from a carbonate-rich layer in the upper two meters of a sediment core (N2-KS-44; ~ 1200 m water depth), well above the present-day sulphate-methane transition zone (about 3 m depth) and the presence of gas hydrates in the sediment. The stratigraphy of core N2-KS-44 was established by tuning its downcore Al/Ti profile to a well-dated nearby reference core, and carbonate 230Th/U ages were calculated using... |
| Tipo: Text |
Palavras-chave: Gas hydrates; Pockmarks; U-series; Authigenic carbonates; Niger delta. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00286/39708/41518.pdf |
| |
|
|
| Loncke, L.; Maillard, A.; Basile, C.; Roest, Walter; Bayon, Germain; Gaullier, V.; Pattier, France; Mercier De Lépinay, Marion; Grall, Celine; Droz, L.; Marsset, Tania; Giresse, P.; Caprais, Jean-claude; Cathalot, Cecile; Graindorge, D.; Heuret, A.; Lebrun, J. F.; Bermell, Sylvain; Marcaillou, B.; Sotin, C.; Hebert, B.; Patriat, Martin; Bassetti, M. A.; Tallobre, Cedric; Buscail, R.; Durrieu De Madron, X.; Bourrin, F.. |
| he IGUANES cruise took place in May 2013 on the R/V L'Atalante along the Demerara passive transform margin off French Guiana and Surinam. Seismic, multibeam and chirp acquisitions were made. Piston cores were collected for pore geochemistry and sedimentology. A mooring was deployed on the sea-bottom for 10 months (temperature, salinity, turbidity and current measurements). This new dataset highlights the lateral variability of the 350 km-long Guiana–Surinam transform margin due to the presence of a releasing bend between two transform segments. The adjacent Demerara Plateau is affected by a 350 km-long giant slide complex. This complex initiated in Cretaceous times and was regularly reactivated until recent times. Since the Miocene, contourite processes... |
| Tipo: Text |
|
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00428/53942/55285.pdf |
| |
| Registros recuperados: 29 | |
|
|
|
