Consulta: creatorFacets:"Etoubleau, Joel"
Registros recuperados: 32
Data/hora: 09/06/2024 05:46:15

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments
Provedor de dados: 5
Autores: Ciobanu, Maria Cristina; Rabineau, Marina; Droz, Laurence; Revillon, Sidonie; Ghiglione, J. -f.; Dennielou, Bernard; Jorry, Stephan; Kallmeyer, J.; Etoubleau, Joel; Pignet, Patricia; Crassous, Philippe; Vandenabeele-trambouze, Odile; Laugier, J.; Guegan, Matthieu; Godfroy, Anne; Alain, Karine.
An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine...
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00090/20171/17826.pdf

Chemical systematics of an intermediate spreading ridge: The Pacific-Antarctic Ridge between 56 degrees S and 66 degrees S
Provedor de dados: 5
Autores: 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

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
Provedor de dados: 5
Autores: 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.
Tipo: Text
Ano: 1983
URL: http://archimer.ifremer.fr/doc/00311/42189/41490.pdf

Hf and Nd isotope records of West African monsoon precipitation in sediments from the Niger Delta
Provedor de dados: 5
Autores: Bayon, Germain; Etoubleau, Joel; Ponzevera, Emmanuel; Voisset, Michel.
Tipo: Text
Ano: 2010
URL: http://archimer.ifremer.fr/doc/00023/13413/10490.pdf

Mineralogy, fluid inclusions and stable isotope study of epithermal Au-Ag-Bi-Te mineralization from the SE Afar Rift (Djibouti)
Provedor de dados: 5
Autores: Moussa, N.; Boiron, M.c-; Grassineau, N.v.; Asael, Dan; Fouquet, Yves; Le Gall, Bernard; Rolet, Joël; Etoubleau, Joel; Delacourt, Christophe.
In this paper, the mineralogy, fluid inclusions and stable isotopes of hydrothermal veins from the SE part of the Afar Rift (Djibouti) were studied. Mineralization occurs as gold-silver in quartz/carbonate veins and is mainly associated with felsic volcanism. The morphologies and textures of quartz show crustiform colloform banding, massive and breccias. Microthermometric measurements were made on quartz-hosted two phases (liquid + vapor) inclusions. Mean homogenization temperature ranges from 150°C to 340°C and ice-melting temperatures range from -0.2°C to - 1.6°C indicating that inclusion solutions contain 0.35 to 2.7 eq. wt. % NaCl. Furthermore, δ18O and δ13C values from calcite range from 3.7 to 26.6 ‰ and -7.5 to 0.3 ‰, respectively. The presence of...
Tipo: Text
Palavras-chave: Fluid inclusions; Stable isotopes; Hydrothermal; Epithermal system; SE Afar Rift; Djibouti.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00494/60528/63991.pdf

Determination of Rare Earth Elements, Sc, Y, Zr, Ba, Hf and Th in Geological Samples by ICP-MS after Tm Addition and Alkaline Fusion
Provedor de dados: 5
Autores: 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

Multi-disciplinary investigation of fluid seepage on an unstable margin: The case of the Central Nile deep sea fan
Provedor de dados: 5
Autores: Bayon, Germain; Loncke, L.; Dupre, Stephanie; Caprais, Jean-claude; Ducassou, E.; Duperron, Sebastien; Etoubleau, Joel; Foucher, Jean-paul; Fouquet, Yves; Gontharet, S.; Henderson, G. M.; Huguen, Caroline; Klaucke, I.; Mascle, J.; Migeon, S.; Olu-le-roy, Karine; Ondreas, Helene; Pierre, C.; Sibuet, Myriam; Stadnitskaia, A.; Woodside, J.
We report on a multidisciplinary study of cold seeps explored in the Central Nile deep-sea fan of the Egyptian margin. Our approach combines in situ seafloor observation, geophysics, sedimentological data, measurement of bottom-water methane anomalies, pore-water and sediment geochemistry, and Th-230/U dating of authigenic carbonates. Two areas were investigated, which correspond to different sedimentary provinces. The lower slope, at similar to 2100 m water depth, indicates deformation of sediments by gravitational processes, exhibiting slope-parallel elongated ridges and seafloor depressions. In contrast, the middle slope, at similar to 1650 m water depth, exhibits a series of debris-flow deposits not remobilized by post-depositional gravity processes....
Tipo: Text
Palavras-chave: Authigenic carbonate; U Th; Cold seep; Continental margin; Nile.
Ano: 2009
URL: http://archimer.ifremer.fr/doc/2009/publication-6586.pdf

Focus on sulfur count rates along marine sediment cores acquired by XRF Core Scanner
Provedor de dados: 5
Autores: 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...
Tipo: Text
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00346/45731/45376.pdf

Investigation on the geochemical dynamics of a hydrate-bearing pockmark in the Niger Delta
Provedor de dados: 5
Autores: 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

Ni-Cu-Co-rich hydrothermal manganese mineralization in the Wallis and Futuna back-arc environment (SW Pacific)
Provedor de dados: 5
Autores: Pelleter, Ewan; Fouquet, Yves; Etoubleau, Joel; Cheron, Sandrine; Labanieh, Shasa; Josso, Pierre; Bollinger, Claire; Langlade, Jessica.
The Wallis and Futuna back-arc system is a complex area composed of at least two active oceanic spreading centers (Futuna and Alofi spreading centers) and young volcanic zones characterized by diffuse magmatism locally affected by the Samoan hotspot. This geological setting is favorable to the establishment of hydrothermal systems either high-temperature (HT) hydrothermal venting or low-temperature (LT) diffuse flow. During the 2010 Futuna cruise aboard R/V L'Atalante, three remarkable inactive LT Fe-Si-Mn deposits have been discovered (i.e. Utu Uli, Anakele and Utu Sega). Some of the Mn-rich precipitates exhibit the highest base metals concentrations so far recorded in ferromanganese rocks including the well-documented hydrogenetic crusts and polymetallic...
Tipo: Text
Palavras-chave: Hydrothermal; Diffuse flow; Manganese oxyhydroxides; Metal-rich; Seafloor; Wallis and Futuna Island; South-West Pacific.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00350/46164/45862.pdf

Formation of carbonate chimneys in the Mediterranean Sea linked to deep-water oxygen depletion
Provedor de dados: 5
Autores: 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...
Tipo: Text
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00156/26734/24854.pdf

Response to Comments on "Intensifying Weathering and Land Use in Iron Age Central Africa"
Provedor de dados: 5
Autores: Bayon, Germain; Dennielou, Bernard; Etoubleau, Joel; Ponzevera, Emmanuel; Toucanne, Samuel; Bermell, Sylvain.
Tipo: Text
Ano: 2012
URL: http://archimer.ifremer.fr/doc/00092/20327/18004.pdf

Campagne HYDROFAST: Etudes quantitatives de l'activité hydrothermale sur la Ride-Est Pacifique à 13°N
Provedor de dados: 5
Autores: 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

Apport des techniques par rayons X à la caractérisation des encroûtements cobaitifères océaniques
Provedor de dados: 5
Autores: 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

U-Th isotope constraints on gas hydrate and pockmark dynamics at the Niger delta margin
Provedor de dados: 5
Autores: 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

Rare earth elements and neodymium isotopes in sedimentary organic matter
Provedor de dados: 5
Autores: Freslon, Nicolas; Bayon, Germain; Toucanne, Samuel; Bermell, Sylvain; Bollinger, Claire; Chéron, Sandrine; Etoubleau, Joel; Germain, Yoan; Khripounoff, Alexis; Ponzevera, Emmanuel; Rouget, Marie Laure.
We report rare earth element (REE) and neodymium (Nd) isotope data for the organic fraction of sediments collected from various depositional environments, i.e. rivers (n=25), estuaries (n=18), open-ocean settings (n=15), and cold seeps (n=12). Sedimentary Organic Matter (SOM) was extracted using a mixed hydrogen peroxide/nitric acid solution (20%-H2O2 – 0.02M-HNO3), after removal of carbonate and oxy-hydroxide phases with dilute hydrochloric acid (0.25M-HCl). A series of experimental tests indicate that extraction of sedimentary organic compounds using H202 may be complicated occasionally by partial dissolution of sulphide minerals and residual carbonates. However, this contamination is expected to be minor for REE because measured concentrations in H2O2...
Tipo: Text
Palavras-chave: Organic matter; Rare earth elements; REE; Neodymium isotopes; ΕNd; Sediment; Boundary Exchange; Paleoceanography.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00191/30250/28682.pdf

Mesure du phosphore dans les eaux naturelles : contamination potentielle par la verrerie
Provedor de dados: 5
Autores: 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

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
Provedor de dados: 5
Autores: 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

Evidence from Tm anomalies for non-CI refractory lithophile element proportions in terrestrial planets and achondrites
Provedor de dados: 5
Autores: 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...
Tipo: Text
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00302/41338/40524.pdf

The control of weathering processes on riverine and seawater hafnium isotope ratios
Provedor de dados: 5
Autores: Bayon, Germain; Vigier, Nathalie; Burton, Kevin W.; Brenot, Agnès; Carignan, Jean; Etoubleau, Joel; Chu, Nan-chin.
Hafnium Hf-176/Hf-177 isotope ratio variations in marine records are thought to reflect changes in continental weathering through time, but the behavior of Hf in rivers, and during weathering, is not well understood. Here, we present Hf-176/Hf-177 data for rivers, bedrock, soils, and leaching experiments for the Moselle basin, Vosges, France. These data strongly suggest that the Hf-176/Hf-177 composition of river waters is controlled by preferential dissolution of accessory phases (i.e., apatite, sphene) versus more resistant minerals (e.g., K-feldspar) and linked to the intensity of silicate weathering. Estimates for the global isotopic composition of riverine Hf suggest that the ocean Hf budget may be dominated by river input, and variations seen in...
Tipo: Text
Palavras-chave: Ocean chemistry; Silicate weathering; Rivers; Hafnium isotopes.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/2006/publication-2078.pdf

Hf and Nd isotopes in marine sediments: Constraints on global silicate weathering
Provedor de dados: 5
Autores: 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

Sr/Ca and Mg/Ca ratios in Niger Delta sediments: Implications for authigenic carbonate genesis in cold seep environments
Provedor de dados: 5
Autores: Bayon, Germain; Pierre, C; Etoubleau, Joel; Voisset, Michel; Cauquil, E; Marsset, Tania; Sultan, Nabil; Le Drezen, Eliane; Fouquet, Yves.
We report on a reconnaissance analysis of the geochemical composition of authigenic carbonates and sediment samples collected from various seepage sites on the Niger deep-sea fan. Our aim has been to investigate whether evidence for the presence of authigenic carbonates and gas hydrates within sediments is discernible from solid-phase sediment geochemistry. We show that sedimentary Sr/Ca and Mg/Ca ratios can be used to infer the presence of authigenic aragonite (Sr-rich) and Mg-rich carbonate phases (high-Mg calcite, dolomite) in cold seep settings. Using Sr/Ca and Mg/Ca ratios, the proportion (wt.%) of authigenic carbonates in Niger Fan sediments can be calculated from a mixing model between sediment fractions of terrigenous material, biogenic calcite,...
Tipo: Text
Palavras-chave: Niger Delta; Gas hydrates; Cold seeps; Mg/Ca; Sr/Ca; Authigenic carbonates.
Ano: 2007
URL: http://archimer.ifremer.fr/doc/2007/publication-2696.pdf

Geochemical Dynamics of the Natural-Gas Hydrate System in the Sea of Marmara, Offshore Turkey
Provedor de dados: 5
Autores: 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

Ferromanganese nodule fauna in the Tropical North Pacific Ocean: Species richness, faunal cover and spatial distribution
Provedor de dados: 5
Autores: 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

A New Discrimination Scheme for Oceanic Ferromanganese Deposits using High Field Strength and Rare Earth Elements
Provedor de dados: 5
Autores: 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

Rare earth elements and neodymium isotopes in world river sediments revisited
Provedor de dados: 5
Autores: Bayon, Germain; Toucanne, Samuel; Skonieczny, Charlotte; Andre, L.; Bermell, Sylvain; Cheron, Sandrine; Dennielou, Bernard; Etoubleau, Joel; Freslon, Nicolas; Gauchery, T.; Germain, Yoan; Jorry, Stephan; Menot, G.; Monin, L.; Ponzevera, Emmanuel; Rouget, M. -l.; Tachikawa, K.; Barrat, Jean-alix.
Over the past decades, rare earth elements (REE) and their radioactive isotopes have received tremendous attention in sedimentary geochemistry, as tracers for the geological history of the continental crust and provenance studies. In this study, we report on elemental concentrations and neodymium (Nd) isotopic compositions for a large number of sediments collected near the mouth of rivers worldwide, including some of the world’s major rivers. Sediments were leached for removal of non-detrital components, and both clay and silt fractions were retained for separate geochemical analyses. Our aim was to re-examine, at the scale of a large systematic survey, whether or not REE and Nd isotopes could be fractionated during Earth surface processes.  Our results...
Tipo: Text
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00276/38733/37249.pdf

High frequency of sediment gravity flow events in the Var submarine canyon (Mediterranean Sea)
Provedor de dados: 5
Autores: 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

Intensifying Weathering and Land Use in Iron Age Central Africa
Provedor de dados: 5
Autores: 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

Multidisciplinary investigation on cold seeps with vigorous gas emissions in the Sea of Marmara (MarsiteCruise): Strategy for site detection and sampling and first scientific outcome
Provedor de dados: 5
Autores: Ruffine, Livio; Ondreas, Helene; Blanc-valleron, Marie-madeleine; Teichert, Barbara M. A.; Scalabrin, Carla; Rinnert, Emmanuel; Birot, Dominique; Croguennec, Claire; Ponzevera, Emmanuel; Pierre, Catherine; Donval, Jean-pierre; Alix, Anne-sophie; Germain, Yoan; Bignon, Laurent; Etoubleau, Joel; Caprais, Jean-claude; Knoery, Joel; Lesongeur, Francoise; Thomas, Bastien; Roubi, Angelique; Legoix, Ludovic Nicolas; Burnard, Pete; Chevalier, Nicolas; Lu, Hailong; Dupre, Stephanie; Fontanier, Christophe; Dissard, Delphine; Olgun, Nazli; Yang, Hailin; Strauss, Harald; Ozaksoy, Volkan; Perchoc, Jonathan; Podeur, Christian; Tarditi, Corinne; Ozbeki, Eyyup; Guyader, Vivien; Marty, Bernard; Madre, David G; Pitel-roudaut, Mathilde; Grall, Celine; Embriaco, Davide; Polonia, Mina; Gasperini, Lucas; Cagatay, M. Namik; Henry, Pierre; Geli, Louis.
MarsiteCruise was undertaken in October/November 2014 in the Sea of Marmara to gain detailed insight into the fate of fluids migrating within the sedimentary column and partially released into the water column. The overall objective of the project was to achieve a more global understanding of cold-seep dynamics in the context of a major active strike-slip fault. Five remotely operated vehicle (ROV) dives were performed at selected areas along the North Anatolian Fault and inherited faults. To efficiently detect, select and sample the gas seeps, we applied an original procedure. It combines sequentially (1) the acquisition of ship-borne multibeam acoustic data from the water column prior to each dive to detect gas emission sites and to design the tracks of...
Tipo: Text
Palavras-chave: Acoustic survey; Authigenic carbonates; Biogeochemistry; Chemical analyses; Cold seeps; Dissolved major elements; Fluid seepage; Geology; In situ Raman analysis; Methane; ROV dives.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00433/54434/55783.pdf

Enargite-luzonite hydrothermal vents in Manus Back-Arc Basin: submarine analogues of high-sulfidation epithermal mineralization
Provedor de dados: 5
Autores: 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

Volcanic and hydrothermal processes in submarine calderas: the Kulo Lasi example (SW Pacific)
Provedor de dados: 5
Autores: Fouquet, Yves; Pelleter, Ewan; Konn, Cecile; Chazot, Gilles; Dupre, Stephanie; Alix, Anne-sophie; Cheron, Sandrine; Donval, Jean-pierre; Guyader, Vivien; Etoubleau, Joel; Charlou, Jean-luc; Labanieh, Shasa; Scalabrin, Carla.
The study area is located at the transition between the northern end of the Tonga Trench and the North Fiji fracture zone, where tectonic movements are reputed to be the fastest in the world. To the southeast of Futuna Island, a broad area of volcanism occurs within a region characterized by a change in the tectonic fabric between a NE-SW oriented volcanic graben and the N-S oriented Alofi ridge. In 2010, the active volcano Kulo Lasi, which represents the most recent volcanic episode in the Futuna area, was discovered in the center of this extensive volcanic zone. Kulo Lasi is a 20 km diameter shield volcano that rises 400 m above the seafloor. It is composed of basaltic to trachy-andesitic lava with no obvious geochemical affinity with the Tonga...
Tipo: Text
Palavras-chave: Subaqueous volcanism; Hydrothermal activity; Kulo Lasi caldera; Sulfides; SW Pacific.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00445/55633/57279.pdf

Methanogenesis and clay minerals diagenesis during the formation of dolomite nodules from the Tortonian marls of southern Spain
Provedor de dados: 5
Autores: 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