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Mas, Virginie. |
In the framework of the HERMES European project, this study aims to characterize the sedimentary processes acting in the Var turbiditic system, their impact on the morphology, and their evolution through time and space. This work uses data acquired along the system, including interface cores, acoustic data, and measurement in the water column (temperature, particulate fluxes, speed and direction of the currents) thanks to mooring lines. The Var turbiditic system is under the influences of the Northern Current and of the Var river by a direct connection. Sedimentary processes are related to gravity-driven currents, oceanic currents which remobilizes sediments and hemipelagic decantation. Gravity-driven processes are dominant and are responsible of 80% of... |
Tipo: Text |
Palavras-chave: Var; Méditerranée; Bassin Ligure; Système turbiditique; Processus gravitaires; Courant de turbidité; Hyperpycnal; Crue; Var; Méditerranée; Ligurian Basin; Turbiditic system; Gravity-driven flows; Turbidity flows; Hyperpycnal; Flood. |
Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00001/11219/7652.pdf |
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Mas, Virginie; Mulder, T.; Dennielou, Bernard; Schmidt, S.; Khripounoff, Alexis; Savoye, Bruno. |
The Var turbidite system is a small sandy system located in the Ligurian Basin (Mediterranean Sea). It is active during present sea-level highstand and shows four types of sediment transfer processes: (1) low-density turbidity surges generated by small-scale failures (2) low-magnitude, high-frequency (yearly) hyperpycnal turbid plumes, (3) high-magnitude, less-frequent, hyperpycnal currents and (4) high-magnitude flows generated by large slope failures. These processes have different imprints on the morphology of the system. Inversely, the topography plays a role on the behaviour of these flows. The depositional and erosional architecture of the system has been investigated in detail on the basis of SAR imagery and a set of cores using an interface corer... |
Tipo: Text |
Palavras-chave: Var; France; Gravity processes; Mediterranean; Turbidity current; Hyperpycnal; Flood. |
Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00013/12458/11862.pdf |
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Denis, Delphine; Crosta, X; Zaragosi, S; Romero, O; Martin, B; Mas, Virginie. |
A 40 m long sediment core covering the 1000-9600 years BP period was retrieved from the Dumont d'Urville Trough off Adelie Land, East Antarctica, during the MD 130-Images X-CADO cruise. This sedimentary sequence allows the documentation of changes in climate seasonality during the Holocene. Here we show preliminary results of diatom communities, lithic grain distribution and titanium content measured on two 30 cm long sequences of thin sections. The two sequences originate from two different climate regimes, the colder Neoglacial and the warmer Hypsithermal. Proxies were measured at microscale resolution on 25 laminations for the Neoglacial and 14 laminations for the Hypsithermal. The two sequences reveal alternating light-green and dark-green laminae.... |
Tipo: Text |
Palavras-chave: East Antarctica; Sea ice; Seasonality; Diatom ooze; Laminated sediments; Holocene; Adelie Land. |
Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2275.pdf |
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Heimbuerger, Lars-eric; Cossa, Daniel; Thibodeau, Benoit; Khripounoff, Alexis; Mas, Virginie; Chiffoleau, Jean-francois; Schmidt, Sabine; Migon, Christophe. |
The magnitude and the chronology of anthropogenic impregnation by Hg and other trace metals of environmental concern (V, Cr, Ni, Cu, Zn, Ag, Cd and Pb, including its stable isotopes) in the sediments are determined at the DYFAMED station, a site in the Ligurian Sea (Northwestern Mediterranean) chosen for its supposed open-sea characteristics. The DYFAMED site (VD) is located on the right levee of the Var Canyon turbidite system, at the end of the Middle Valley. In order to trace the influence of the gravity current coming from the canyon on trace metal distribution in the sediment, we studied an additional sediment core (VA) from a terrace of the Var Canyon, and material collected in sediment traps at the both sites at 20 m above sea bottom. The patterns... |
Tipo: Text |
Palavras-chave: Marine sediments; Sediment traps; Mercury; Trace metals; Lead isotopes; Geochronology. |
Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00073/18435/16125.pdf |
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