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| Bailly Du Bois, Pascal; Dumas, Franck; Solier, L. |
| This work aims to validate the dispersion parameters of hydrodynamic models for the short term (hour to week), and short distances (100 m - 30 km), by using high precision and high frequency measurements of tritium obtained in the release plume. An instantaneous 2D hydrodynamic model has been developed with a mesh size of 110m and an area of 5050 km. More than 7,000 samples have been collected and measured for tritium concentrations in 2002 and 2003. Currents and bathymetric measurements, as well as drifters observations complete these measurements. Results confirm the efficiency of the hydrodynamic model, main differences being attributable to bathymetry incertitudes. After calibration, the model gives accurate results during six hours following a... |
| Tipo: Text |
Palavras-chave: Dispersion parameter; Plume; Macro tidal sea; Hydrodynamic model. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/2005/publication-544.pdf |
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| Sauter, Eberhard; Muyakshin, Sergey; Charlou, Jean-luc; Schluter, Michael; Boetius, Antje; Jerosch, Kerstin; Damm, Ellen; Foucher, Jean-paul; Klages, Michael. |
| The assessment of climate change factors includes a constraint of methane sources and sinks. Although marine geological Sources are recognized as significant, unfortunately, most submarine sources remain poorly quantified. Beside cold vents and coastal anoxic sediments, the large number of submarine mud volcanoes (SMV) may contribute significantly to the oceanic methane pool. Recent research suggests that methane primarily released diff-usively from deep-sea SMVs is immediately oxidized and, thus, has little climatic impact. New hydro-acoustic, Visual, and geochemical observations performed at the deep-sea mud volcano Hakon Mosby reveal the discharge of gas hydrate-coated methane bubbles and gas hydrate flakes forming huge methane plumes extending from... |
| Tipo: Text |
Palavras-chave: Hydro acoustics; Gas hydrates; Gas bubbles; Submarine mud volcanoes; Methane budget; Plume; Methane sources. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1345.pdf |
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| Revillon, Sidonie; Guillou, Herve; Maury, Rene C.; Chauvel, Catherine; Aslanian, Daniel; Pelleter, Ewan; Scao, Vincent; Loubrieu, Benoit; Patriat, Martin. |
| The Marquesas Island chain in Polynesia is quite unusual because the alignment of the islands on the Pacific oceanic plate (N40°W) does not follow the plate motion in the region (N65°W). The exact location of the active hotspot is unknown but has been predicted to underlie the Marquesas Fracture Zone Ridge. Nevertheless, no concrete evidence exists. Here, we document the occurrence on this ridge of fresh tephrites dated at ~ 92 ka by the 40Ar-39Ar method. The lavas dredged on a small seamount have trace element contents and Sr, Nd, Pb isotopic compositions typical of the southwest Marquesas Islands, the Fatu Hiva group. This discovery demonstrates that the Marquesas plume is still active and it puts new constraints on its present location. It also supports... |
| Tipo: Text |
Palavras-chave: Submarine volcanism; Ar-40-Ar-39 ages; Geochemistry; Plume; Marquesas; French Polynesia. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00407/51832/52431.pdf |
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