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| Registros recuperados: 55 | |
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| Jean-baptiste, Philippe; Fourre, Elise; Charlou, Jean-luc; Donval, Jean-pierre; Correge, Thierry. |
| Historical descriptions of the Clipperton lagoon appear to converge on the fact that it became isolated from the surrounding ocean around 1858. Since then, because of the high precipitation rate which largely exceeds evaporation in this region of the eastern tropical Pacific, a brackish lens has formed on top of the saline oceanic waters. In 1980, literature data show that the thickness of this water body was reaching 14 m. During the 2005 Etienne's Clipperton expedition, we collected lagoon water on two vertical profiles. Salinity, delta O-18 and tritium analyses were performed on these samples with the objective of gaining further insight into the lagoon hydrology and age of the deep waters. The upper 15 m were characterized by low salinities (5.4 +/-... |
| Tipo: Text |
Palavras-chave: Oxygen isotopes; Tritium; Enclosed lagoon hydrology; Clipperton atoll. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6457.pdf |
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| Konn, Cecile; Charlou, Jean-luc; Donval, Jean-pierre; Holm, N. G.; Dehairs, F.; Bouillon, S.. |
| The first building blocks of life could be produced in ultramafic-hosted hydrothermal systems considering the large amounts of hydrogen and methane generated by serpentinisation and Fischer-Tropsch-Type synthesis, respectively, in those systems. The purpose of this study was to detect and characterise organic molecules in hydrothermal fluids from ultramafic-hosted hydrothermal systems in the Mid-Atlantic Ridge (MAR) region. During the EXOMAR cruise 2005, fluids from the Rainbow (36°14'N) and the Lost City (30°N) hydrothermal fields were collected and treated by Stir Bar Sorptive Extraction (SBSE) and Solid Phase Extraction (SPE). The extracts were analysed by Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS) and GC-MS, respectively.... |
| Tipo: Text |
Palavras-chave: Serpentinisation; Organic; Ultramafic; Hydrothermal; Origin of life. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00067/17828/15576.pdf |
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| Charlou, Jean-luc; Martin, J.l.. |
| Le but du travail de recherhche dont les résultats sont exposé dans le présent rapport était de faire le point sur l'état de pollution ou de non poluution de la rade de Brest par les métaux issus de la réparation navale. Le rapport traitant de la technologie relative au carénage, rédigé sous la forme définitive (CROQUETTE, 1976) montrait que le toxique essentiel entrant dans la composition des peintures antifouling était le cuivre. Les recherches entreprises ont donc porté essentiellement sur ce métal. Au cours de notre travail, deux voies distinctes de recherche ont été abordées. Nous avons tout d'abord considéré les aspects hydro-géochimiques du comportement du cuivre dans la rade de Brest. Les analyses ont porté sur l'eau, et sur les sédiments selon... |
| Tipo: Text |
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| Ano: 1976 |
URL: http://archimer.ifremer.fr/doc/00105/21619/19199.pdf |
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| Roussel, Erwan; Sauvadet, Anne-laure; Chaduteau, Carine; Fouquet, Yves; Charlou, Jean-luc; Prieur, Daniel; Cambon, Marie-anne. |
| P>The distribution of the archaeal communities in deep subseafloor sediments [0-36 m below the seafloor (mbsf)] from the New Caledonia and Fairway Basins was investigated using DNA- and RNA-derived 16S rRNA clone libraries, functional genes and denaturing gradient gel electrophoresis (DGGE). A new method, Co-Migration DGGE (CM-DGGE), was developed to access selectively the active archaeal diversity. Prokaryotic cell abundances at the open-ocean sites were on average similar to 3.5 times lower than at a site under terrestrial influence. The sediment surface archaeal community (0-1.5 mbsf) was characterized by active Marine Group 1 (MG-1) Archaea that co-occurred with ammonia monooxygenase gene (amoA) sequences affiliated to a group of uncultured... |
| Tipo: Text |
Palavras-chave: Marine subsurface sediments; Sea floor biosphere; Gradient gel electrophoresis; Microbial communities; Molecular diversity; Anaerobic oxidation; Sequence alignment; Phylogenetic trees; Extracellular DNA; Methane hydrate. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6801.pdf |
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| Charlou, Jean-luc; Charlot, Michèle. |
| L'aspect géochimique des incidences de la réparation navale par les apports en traces métalliques (cuivre en particulier) contenus dans les peintures antifouling est étudié dans la zone N.E. de la rade de Brest. Les campagnes d'analyses d'eaux et les carottages sédimentaires ont permis de définir plusieurs zones touchées directement ou indirectement par ces rejets. L'étude chimique de la fraction fine inférieure à 63 microns des sédiments prélevés a mis en évidence une dissémination régulière en Cu - Pb - Zn en surface. Les évolutions des concentrations de ces métaux en fonction de la profondeur sont aussi tracées : les métaux semblent suivre la même loi d'accumulation. En laboratoire il a été possible d'étudier certains facteurs intervenant lors de la... |
| Tipo: Text |
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| Ano: 1976 |
URL: http://archimer.ifremer.fr/doc/00132/24327/22326.pdf |
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| Wilson, Cara; Speer, Kevin; Charlou, Jean-luc; Bougault, Henri; Klinkhammer, Gary. |
| As part of the French-American Ridge Atlantic program the French-American Zero-Angle Photon Spectrometer and Rocks (FAZAR) cruise conducted water column studies between 33 and 40 degrees N along the Mid-Atlantic Ridge (MAR)) to detect hydrothermal activity and map its influence, This paper describes the large-scale hydrography within the axial valley, with particular emphasis on the hydrothermally active Lucky Strike segment (37 degrees 17'N). The FAZAR study area is affected be the presence of the Azores Current and Mediterranean Water (MW). Although the MW core has been mapped as far north as 50 degrees N off the ridge; the northern boundary Of the MW within the MAR in the FAZAR study area exists as a strong front south of the Azores platform. This front... |
| Tipo: Text |
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| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00069/18038/15586.pdf |
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| Bayon, Germain; Birot, Dominique; Ruffine, Livio; Caprais, Jean-claude; Ponzevera, Emmanuel; Bollinger, C.; Donval, Jean-pierre; Charlou, Jean-luc; Voisset, Michel; Grimaud, S.. |
| For many trace elements, continental margins are the location of intense exchange processes between sediment and seawater, which control their distribution in the water column, but have yet to be fully understood. In this study, we have investigated the impact of fluid seepage at cold seeps on the marine cycle of neodymium. We determined dissolved and total dissolvable (TD) concentrations for REE and well-established tracers of fluid seepage (CH4, TDFe, TDMn), and Nd isotopic compositions in seawater samples collected above cold seeps and a reference site (i.e. away from any fluid venting area) from the Niger Delta margin. We also analyzed cold seep authigenic phases and various core-top sediment fractions (pore water, detrital component, easily leachable... |
| Tipo: Text |
Palavras-chave: Rare earth elements; Neodymium isotopes; Seawater; Cold seeps; Fe-Mn oxyhydroxides; Benthic fluxes. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00066/17754/15571.pdf |
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| Langmuir, C; Charlou, Jean-luc; Colodner, D; Costa, I; Desbruyeres, Daniel; Desonie, D; Emerson, T; Fornari, D; Fouquet, Yves; Humphris, S; Fiala-medioni, A; Saldanha, L; Sours-page, R; Thatcher, M; Tivey, M.k; Van Dover, C; Von Damm, K; Wiese, K; Wilson, C. |
| Tipo: Text |
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| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00070/18096/15644.pdf |
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| Konn, Cecile; Charlou, Jean-luc; Holm, N. G.; Mousis, O.. |
| Both hydrogen and methane are consistently discharged in large quantities in hydrothermal fluids issued from ultramafic-hosted hydrothermal fields discovered along the Mid-Atlantic Ridge. Considering the vast number of these fields discovered or inferred, hydrothermal fluxes represent a significant input of H-2 and CH4 to the ocean. Although there are lines of evidence of their abiogenic formation from stable C and H isotope results, laboratory experiments, and thermodynamic data, neither their origin nor the reaction pathways generating these gases have been fully constrained yet. Organic compounds detected in the fluids may also be derived from abiotic reactions. Although thermodynamics are favorable and extensive experimental work has been done on... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00270/38139/36281.pdf |
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| Fourre, E; Jean Baptiste, P; Charlou, Jean-luc; Donval, Jean-pierre; Ishibashi, J. |
| We present isotopic analysis of helium in hydrothermal fluids from the Manus back-arc basin, collected during the French-Japanese Manusflux and Manaute cruises in 1995 and 2000, respectively. The helium isotope composition of the fluids is comparable to that measured elsewhere in similar subduction environments, with He-3/He-4 values (7.4 to 7.9 R-a) slightly lower than typical MORB values, except on the Manus Spreading Center (MSC) where higher values (12 +/- 0.1 R-a) are observed. The causal link between the narrow spatial extent of the He-3/He-4 anomaly at the MSC and a He-3-rich deep mantle component remains elusive, based on available geophysical data. Thus, the Manus Spreading Center results may be an interesting example of small scale upper-mantle... |
| Tipo: Text |
Palavras-chave: Western Pacific; Manus Basin; Back arc basins; Hydrothermal fluids; Helium isotopes. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-4203.pdf |
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| Bourry, Christophe; Charlou, Jean-luc; Donval, Jean-pierre; Brunelli, M; Focsa, C; Chazallon, B. |
| Natural gas hydrates recovered from the Congo- Angola basin and Nigerian margins are analyzed by synchrotron X- ray powder diffraction. Biogenic methane is the most abundant gas trapped in the samples and others minor components (CO2, H2S) are co-clathrated in a type I cubic lattice structure. The refinement for the type I structure gives lattice parameters of a = 11.8646 ( 39) angstrom and a = 11.8619 ( 23) angstrom for specimens from Congo- Angola and Nigerian margins respectively at 90 K. These values, intermediate between the lattice constant of less pure methane specimens and pure artificial methane hydrates, indicate that lattice constants can be affected by the presence of encaged CO2, H2S and other gas molecules, even in small amounts. Thermal... |
| Tipo: Text |
Palavras-chave: Synchrotron X ray diffraction; Thermal expansion; Natural clathrate hydrates. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3511.pdf |
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| Bougault, Henri; Charlou, Jean-luc; Fouquet, Yves; Needham, Hubert D; Vaslet, Nathalie; Appriou, Pierre; Jean Baptiste, Philippe; Rona, Peter A; Dmitriev, Leonid; Silantiev, Sergei. |
| Tipo: Text |
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| Ano: 1993 |
URL: http://archimer.ifremer.fr/doc/00070/18116/15664.pdf |
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| Ruffine, Livio; Caprais, Jean-claude; Bayon, Germain; Riboulot, Vincent; Donval, Jean-pierre; Etoubleau, Joel; Birot, Dominique; Pignet, Patricia; Rongemaille, Emmanuelle; Chazallon, Bertrand; Grimaud, Sylvie; Adamy, Jerome; Charlou, Jean-luc; Voisset, Michel. |
| A joint industrial project with IFREMER and Total provides insights into the tectonic setting and the geochemistry of a large active pockmark offshore W-Africa in the Niger Delta. The study combines both geophysical (seismic) and geochemical data to infer the dynamics of a 300 m wide pockmark located at 667 m water depth. Two Calypso cores, one at the centre and one outside the pockmark, along with three box-cores, two inside the pockmark and one outside, were collected to study the geochemistry of gas hydrates, carbonates and pore waters. Two seismic lines, a 3D high resolution random line and a 2D high resolution seismic line, provide a good description of the plumbing of the system. The integrated results depict a very active pockmark characterized by... |
| Tipo: Text |
Palavras-chave: Active pockmark; Anaerobic oxidation of methane; Gas hydrates; Carbonates; Seismic surveys; Fault system; U/Th dating. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00139/24981/23102.pdf |
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| Registros recuperados: 55 | |
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