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Registros recuperados: 31
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A New Discrimination Scheme for Oceanic Ferromanganese Deposits using High Field Strength and Rare Earth Elements ArchiMer
Josso, P.; Pelleter, Ewan; Pourret, O.; Fouquet, Yves; Etoubleau, Joel; Cheron, Sandrine; Bollinger, C..
Ferromanganese (Fe-Mn) deposits constitute a ubiquitous mineral type in oceanic settings, with metal (Cu, Ni, Zn, Co, Pt) and rare earth elements (REE) enrichments of potential economic interest. Routine analysis of trace elements by ICP-MS has advanced our understanding of the impact of hydrogenetic, diagenetic and hydrothermal processes on the mobility and interaction of high field strength elements (HFSE: Zr, Ti) and REE and yttrium (REY) with Fe-Mn oxyhydroxides. Recent discoveries in the French exclusive economic zone (EEZ) of Wallis and Futuna (southwest Pacific Ocean) have brought new insight to the formation of low temperature (LT) hydrothermal Mn deposits and lead us to reconsider the classification and discrimination diagrams for of Fe-Mn...
Tipo: Text Palavras-chave: Ferromanganese mineralization; Hydrogenetic crusts; Nodules; Hydrothermal deposits; Rare earth elements; High field strength elements; Classification.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00350/46156/45854.pdf
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Apport des techniques par rayons X à la caractérisation des encroûtements cobaitifères océaniques ArchiMer
Etoubleau, Joel; Bohn, Marcel; Fouquet, Yves; Cambon, Pierre; Le Suave, Raymond.
A range of X-ray analytical techniques contributes particularly well to the mineralogical and geochemical characterisations of cobalt-rich iron and manganese oxides crusts. X-ray diffraction is used to identify the weak crystallinity of the material. Bulk geochemical characterisation of the crusts is done by X-ray fluorescence for the precise determination of ca. thirty major and trace elements. Fine scale analysis is carried out by electron microprobe to quantitatively map the distribution of elements in oxide phases within the crusts. Microprobe work is essential to obtain the chemical composition of the embedded metallic micro-meteorites.
Tipo: Text
Ano: 2000 URL: http://archimer.ifremer.fr/doc/00000/10415/9517.pdf
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Campagne HYDROFAST: Etudes quantitatives de l'activité hydrothermale sur la Ride-Est Pacifique à 13°N ArchiMer
Bougault, Henri; Appriou, P; Birolleau, A; Charlou, Jean-luc; Crane, K; Etoubleau, Joel; Fouquet, Yves; Gente, P; Harmegnies, Francois; Landure, Jean-yves; Le Noac'H, A; Pelle, Henri; Sichler, Bertrand; Voisset, Michel; Watremez, Pierre; Vaslet, N; Jean Baptiste, P.
Tipo: Text
Ano: 1990 URL: http://archimer.ifremer.fr/doc/00070/18104/15652.pdf
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Chemical systematics of an intermediate spreading ridge: The Pacific-Antarctic Ridge between 56 degrees S and 66 degrees S ArchiMer
Vlastelic, Ivan; Dosso, Laure; Bougault, Henri; Aslanian, Daniel; Geli, Louis; Etoubleau, Joel; Bohn, Marcel; Joron, Jl; Bollinger, C.
Axial bathymetry, major/trace elements, and isotopes suggest:that the Pacific-Antarctic Ridge (PAR) between 56 degrees S and 66 degrees S is devoid of any hotspot influence. PAR (56-66 degrees 5) samples have in-average lower Sr-87/Sr-86 and Nd-143/Nd-144 and higher Pb-206/(204)pb than northern Pacific midocean ridge basalts (MORB), and also than MORE from the other oceans. The high variability of Pb isotopic ratios (compared to Sr and Nd) can be due to either a;general high mu (HIMU) (high U/Pb) affinity of the southern Pacific upper mantle or to a mantle event first recorded in time by Pb isotopes. Compiling the results of this study with those from the PAR between 53 degrees S and 57 degrees S gives a continuous view of mantle characteristics from south...
Tipo: Text
Ano: 2000 URL: https://archimer.ifremer.fr/doc/00000/10578/9396.pdf
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Determination of Rare Earth Elements, Sc, Y, Zr, Ba, Hf and Th in Geological Samples by ICP-MS after Tm Addition and Alkaline Fusion ArchiMer
Bayon, Germain; Barrat, Jean Alix; Etoubleau, Joel; Benoit, Mathieu; Bollinger, Claire; Revillon, Sidonie.
We present a revised method for the determination of concentrations of rare earth (REE) and other trace elements (Y, Sc, Zr, Ba, Hf, Th) in geological samples. Our analytical procedure involves sample digestion using alkaline fusion (NaOH-Na2O2) after addition of a Tm spike, co-precipitation on iron hydroxides, and measurement by sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS). The procedure was tested successfully for various rock types (i.e., basalt, ultramafic rock, sediment, soil, granite), including rocks with low trace element abundances (sub ng g(-1)). Results obtained for a series of nine geological reference materials (BIR-1, BCR-2, UB-N, JP-1, AC-E, MA-N, MAG-1, GSMS-2, GSS-4) are in reasonable agreement with published...
Tipo: Text Palavras-chave: Digestion des Echantillons; Spike de Tm; ICP MS; MatEriaux de rEfErence; Echantillons gEologiques; ElEments du groupe des Terres Rares; Sample digestion; Tm spike; ICP MS; Reference materials; Geological samples; Rare earth elements.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6449.pdf
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Enargite-luzonite hydrothermal vents in Manus Back-Arc Basin: submarine analogues of high-sulfidation epithermal mineralization ArchiMer
Dekov, Vesselin M.; Rouxel, Olivier; Kouzmanov, Kalin; Bindi, Luca; Asael, Dan; Fouquet, Yves; Etoubleau, Joel; Burgaud, Gaetan; Walle, Markus.
Active and inactive hydrothermal chimneys composed almost entirely of enargite and luzonite, rare minerals in seafloor hydrothermal deposits, were found at the summits of two submarine volcanoes, North Su and Kaia Natai, in the Manus Back-Arc Basin. Detailed mineralogical and geochemical studies revealed that most probably these deposits precipitated at T = 200°–330 °C and high fS2. The negative δ34S values (− 8.58 to − 3.70‰) of the enargite-luzonite are best explained by disproportionation reactions of magmatic SO2 and suggest that the high fS2 is likely provided by direct magmatic input of SO2 into the hydrothermal system. Fractionation of Cu stable isotopes during the precipitation of enargite-luzonite (δ65Cu ranges from − 0.20 to + 0.35‰) is inferred...
Tipo: Text Palavras-chave: Enargite; Epithermal; Hydrothermal vent; Luzonite; S-Cu isotopes; Seafloor.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00337/44844/44432.pdf
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Evidence from Tm anomalies for non-CI refractory lithophile element proportions in terrestrial planets and achondrites ArchiMer
Barrat, Jean-alix; Dauphas, N.; Gillet, P.; Bollinger, C.; Etoubleau, Joel; Bischoff, A.; Yamaguchi, A..
Thulium is a heavy rare earth element (REE) whose geochemical behavior is intermediate between Er and Yb, and that is not expected to be decoupled from these elements during accretion of planetary bodies and geological processes. However, irregularities in REE volatilities at higher temperature could have decoupled the REEs relative to one another during the early stages of condensation of the solar nebula. Indeed, positive Tm anomalies are found in some refractory inclusions from carbonaceous chondrites, and it is possible that large scale nebular reservoirs displaying positive or negative Tm anomalies were formed during the early history of the solar system. We analyzed a series of meteorites and terrestrial rocks in order to evaluate the existence of Tm...
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Ano: 2016 URL: https://archimer.ifremer.fr/doc/00302/41338/40524.pdf
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Ferromanganese nodule fauna in the Tropical North Pacific Ocean: Species richness, faunal cover and spatial distribution ArchiMer
Veillette, J; Sarrazin, Jozee; Gooday, A; Galeron, Joelle; Caprais, Jean-claude; Vangriesheim, Annick; Etoubleau, Joel; Christian, J; Juniper, S.
The poorly known ferromanganese nodule fauna is a widespread hard substratum community in the deep sea that will be considerably impacted by large-scale nodule mining operations. The objective of this study was to analyze the spatial distribution of the fauna attached to nodules in the Clarion-Clipperton Fracture Zone at two scales; a regional scale that includes the east (14 degrees N, 130 degrees W) and the west (9 degrees N, 150 degrees W) zones and a local scale in which different geological facies (A, B, C and west) are recognizable. The fauna associated with 235 nodules was quantitatively described: 104 nodules from the east zone (15 of facies A, 50 of facies B and 39 of facies C) and 131 nodules from the west zone. Percent cover was used to quantify...
Tipo: Text Palavras-chave: Environmental impacts; Environmental factors; Geographical distribution; Agglutinated foraminifera; Fixed fauna; Ferromanganese nodules.
Ano: 2007 URL: http://archimer.ifremer.fr/doc/2007/publication-3537.pdf
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Focus on sulfur count rates along marine sediment cores acquired by XRF Core Scanner ArchiMer
Cheron, Sandrine; Etoubleau, Joel; Bayon, Germain; Garziglia, Sebastien; Boissier, Audrey.
The aim of this study is to investigate the information provided by sulfur count rates obtained by X-ray fluorescence core scanner (XRF-CS) along sedimentary records. The analysis of two marine sediment cores from the Niger Delta margin shows that XRF-CS sulfur count rates obtained at the surface of split core sections with XRF-CS correlate with both direct quantitative pyrite concentrations, as inferred from X-ray powder diffraction (XRD) and sulfur determination by wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry, and total dissolved sulfide (TDS) contents in the sediment pore water. These findings demonstrate the potential of XRF-CS for providing continuous profiles of pyrite distribution along split sections of sediment cores. The...
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00346/45731/45376.pdf
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Formation of carbonate chimneys in the Mediterranean Sea linked to deep-water oxygen depletion ArchiMer
Bayon, Germain; Dupre, Stephanie; Ponzevera, Emmanuel; Etoubleau, Joel; Cheron, Sandrine; Pierre, Catherine; Mascle, Jean; Boetius, Antje; De Lange, Gert J..
Marine sediments at ocean margins vent substantial amounts of methane(1,2). Microbial oxidation of the methane released can trigger the precipitation of carbonate within sediments and support a broad diversity of seafloor ecosystems(3,4). The factors controlling microbial activity and carbonate precipitation associated with the seepage of submarine fluid over geological time remain poorly constrained. Here, we characterize the petrology and geochemistry of rocks sampled from metre-size build-ups of methane-derived carbonate chimneys located at the Amon mud volcano on the Nile deep-sea fan. We find that these carbonates comprise porous structures composed of aggregated spherules of aragonite, and closely resemble microbial carbonate reefs forming at present...
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Ano: 2013 URL: http://archimer.ifremer.fr/doc/00156/26734/24854.pdf
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Geochemical Dynamics of the Natural-Gas Hydrate System in the Sea of Marmara, Offshore Turkey ArchiMer
Ruffine, Livio; Fandino Torres, Olivia; Etoubleau, Joel; Cheron, Sandrine; Donval, Jean-pierre; Germain, Yoan; Ponzevera, Emmanuel; Guyader, Vivien; Dennielou, Bernard; Etiope, Giuseppe; Gasperini, Luca; Bortoluzzi, Giovanni; Henry, Pierre; Grall, Celine; Cagatay, M. Namik; Charlou, Jean-luc; Geli, Louis.
Tipo: Text
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00139/24982/23065.pdf
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Hf and Nd isotope records of West African monsoon precipitation in sediments from the Niger Delta ArchiMer
Bayon, Germain; Etoubleau, Joel; Ponzevera, Emmanuel; Voisset, Michel.
Tipo: Text
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00023/13413/10490.pdf
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Hf and Nd isotopes in marine sediments: Constraints on global silicate weathering ArchiMer
Bayon, Germain; Burton, K. W.; Soulet, Guillaume; Vigier, N.; Dennielou, Bernard; Etoubleau, Joel; Ponzevera, Emmanuel; German, C. R.; Nesbitt, R. W..
The combined use of Lu-Hf and Sm-Nd isotope systems potentially offers a unique perspective for investigating continental erosion, but little is known about whether, and to what extent, the Hf-Nd isotope composition of sediments is related to silicate weathering intensity. In this study, Hf and Nd elemental and isotope data are reported for marine muds, leached Fe-oxide fractions and zircon-rich turbidite sands collected off the Congo River mouth, and from other parts of the SE Atlantic Ocean. All studied samples from the Congo fan (muds, Fe-hydroxides, sands) exhibit indistinguishable Nd isotopic composition (epsilon(Nd)similar to - 16), indicating that Fe-hydroxides leached from these sediments correspond to continental oxides precipitated within the...
Tipo: Text Palavras-chave: Congo fan; Seawater array; Continental erosion; Silicate weathering; Hafnium isotopes; Neodymium isotopes.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6451.pdf
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High frequency of sediment gravity flow events in the Var submarine canyon (Mediterranean Sea) ArchiMer
Khripounoff, Alexis; Vangriesheim, Annick; Crassous, Philippe; Etoubleau, Joel.
This study aimed to analyze the role river floods play in triggering gravity flows and to investigate the role of submarine canyon systems as a conduit for terrigenous material to the deep sea. Two years of measurements in the Var canyon at depths ranging from 1200 m to 2350 m indicate that six floods of the Var River triggered hyperpycnal flows, an important mechanism for transporting particulate matter to the deep-sea floor. These sediment gravity flows were characterized by a sudden increase of current velocity that lasted 8 to 22 h and by downward particle fluxes that reached up to 600 g m(-2)d(-1) of particles and 3.1 g m(-2)d(-1) in terms of organic carbon. These large inputs of sediment and organic carbon may have a significant impact on deep-sea...
Tipo: Text Palavras-chave: West Mediterranean Sea; Particle flux; Var canyon; Hyperpycnal flow; Turbidity current.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6640.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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Intensifying Weathering and Land Use in Iron Age Central Africa ArchiMer
Bayon, Germain; Dennielou, Bernard; Etoubleau, Joel; Ponzevera, Emmanuel; Toucanne, Samuel; Bermell, Sylvain.
About 3000 years ago, a major vegetation change occurred in Central Africa, when rainforest trees were abruptly replaced by savannas. The consensus is that the forest disturbance was caused by climate change. We show here that chemical weathering in Central Africa, reconstructed from geochemical analyses of a marine sediment core, intensified abruptly at the same period, departing significantly from the long-term weathering fluctuations related to the Late Quaternary climate. Evidence that this weathering event was also contemporaneous with the migration of Bantu-speaking farmers across Central Africa suggests that human land-use intensification at that time already had a significant impact on the rainforest.
Tipo: Text
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00069/18031/15574.pdf
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Investigation on the geochemical dynamics of a hydrate-bearing pockmark in the Niger Delta ArchiMer
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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Le leg 82 du programme international de forages océaniques profonds (I.O.D.P.) : croûte océanique "normale" ou "anormale" sur la ride médio-Atlantique ; propriétés géochimiques ArchiMer
Bougault, Henri; Cande, S; Mills, W; Curtis, D; Neuser, R; Christie, D; Rideout, M; Etoubleau, Joel; Drake, N; Brannon, J; Weaver, B; Echols, D; Clark, M; Khan, Mj; Hill, I.
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Ano: 1983 URL: http://archimer.ifremer.fr/doc/00311/42189/41490.pdf
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Mesure du phosphore dans les eaux naturelles : contamination potentielle par la verrerie ArchiMer
Aminot, Alain; Kerouel, Roger; Etoubleau, Joel; Cambon, Pierre.
Des mesures de phosphore dans plusieurs échantillons de verres de laboratoire ont été réalisées, après digestion fluorhydrique, par colorimétrie phosphomolybdique. On trouve que les verres peuvent contenir de 0,001 à 0,002 % de phosphore. On montre que la verrerie peut contribuer de manière significative à la contamination en phosphore d'échantillons d'eaux naturelles, notamment d'eau de mer, en raison de la dissolution partielle du verre dans l'échantillon, dans certaines conditions de conservation ou de digestion.
Tipo: Text
Ano: 1991 URL: http://archimer.ifremer.fr/doc/00082/19346/16940.pdf
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Methanogenesis and clay minerals diagenesis during the formation of dolomite nodules from the Tortonian marls of southern Spain ArchiMer
Pierre, Catherine; Rouchy, Jean-marie; Blanc-valleron, Marie-madeleine; Etoubleau, Joel; Fouquet, Yves.
Dolomite nodules are widespread within the Tortonian marls of Fortuna and Lorca basins in southern Spain. They occur as large bodies of various forms (round, ovoid, tabular) that are parallel or secant relative to the stratification. They are massive and present sometimes internal conduits that are considered as drains used for the migration of fluids. This study brings new results on the mineralogy and elemental and isotopic geochemistry of these dolomite nodules to better describe the processes that were occurring during their formation. The diagenetic reactions that have driven authigenic dolomite precipitation within the sediments involved on the one hand methanogenesis that produced 13C-poor CH4 and 13C-rich CO2, on the other hand carbonate and...
Tipo: Text Palavras-chave: Authigenic dolomite nodules; Elemental geochemistry; Oxygen and carbon isotopes; Methanogenesis; Clay minerals diagenesis.
Ano: 2015 URL: https://archimer.ifremer.fr/doc/00266/37752/35803.pdf
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