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Registros recuperados: 15
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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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Altered volcanic deposits as basal failure surfaces of submarine landslides ArchiMer
Miramontes, Elda; Sultan, Nabil; Garziglia, Sebastien; Jouet, Gwenael; Pelleter, Ewan; Cattaneo, Antonio.
One of the main concerns regarding the development of submarine landslides is the role played by weak layers in the failure process and, in particular, their impact in terms of volume, shape, and evolution of mass movements. In the present study we identified a weak layer in the eastern margin of the Corsica Trough (northern Tyrrhenian Sea) that formed the basal failure surface of the Pianosa Slump at 42–50 ka. This layer is characterized by high water content, high plasticity, high compressibility, and post-peak strain softening behavior (i.e., strength loss with increasing strain). These specific mechanical and sedimentological properties seem to be related to the presence of analcime zeolites with a concentration of 2–4% in the muddy sediment. Zeolites...
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Ano: 2018 URL: http://archimer.ifremer.fr/doc/00444/55565/57176.pdf
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ARCHIMEDE - A new software for management of geological and biological samples ArchiMer
Tosello, Vanessa; Borremans, Catherine; Detoc, Jerome; Pelleter, Ewan.
Since 2003, IFREMER manages the marine geology database of Brest (BGMB) which includes information on geological samples (sediment cores and rocks) and geotechnical measurements collected by IFREMER teams and/or resources and related analyses (stratigraphy, lithology, chemistry, grain size). In the same way, the IFREMER Deep Sea Lab database (BIOCEAN) gathers data about biological, sediment and hydrological samples collected by IFREMER biologists and ecologists since 1967. These databases which include several thousands of operations and samples require having a better visibility for the scientific community through the improvement of existing software tools and services. Indeed, according to the current scientific projects and future applications (e.g....
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00363/47372/47358.pdf
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Contribution of resuspended sedimentary particles to dissolved iron and manganese in the ocean: An experimental study ArchiMer
Cheize, Marie; Planquette, H.f.; Fitzsimmons, J.n.; Pelleter, Ewan; Sherrell, R.m.; Lambert, Christophe; Bucciarelli, E.; Sarthou, G.; Le Goff, Marion; Liorzou, Celine; Chéron, Sandrine; Viollier, E.; Gayet, Nicolas.
A number of trace metals play essential roles in marine ecosystem structure and biological productivity. Until recently, it has been argued that phytoplankton access primarily dissolved iron, while particulate iron was considered a refractory material with little use biologically and limited interaction with the dissolved pool. In order to assess the transfer mechanisms between sediment-sourced particulate trace metals and the dissolved pool, we conducted a 14-month incubation that reacted resuspended sediments with natural seawater, both originating from the Kerguelen area (KEOPS cruises; Southern Ocean), in the dark, and at concentrations replicating natural conditions. Three types of sediments were investigated (named BioSi, BioSi + Ca, and Basalt),...
Tipo: Text Palavras-chave: Suspended particle dissolution; Sediment; Iron; Manganese; Biogenic silica; Southern Ocean; Kerguelen.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00460/57197/59166.pdf
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Extensive hydrothermal activity revealed by multi-tracer survey in the Wallis and Futuna region (SW Pacific) ArchiMer
Konn, Cecile; Fourre, E.; Jean-baptiste, P.; Donval, Jean-pierre; Guyader, Vivien; Birot, Dominique; Alix, Anne-sophie; Gaillot, Arnaud; Perez, Florian; Dapoigny, A.; Pelleter, Ewan; Resing, J. A.; Charlou, Jean-luc; Fouquet, Yves.
The study area is close to the Wallis and Futuna Islands in the French EEZ. It exists on the western boundary of the fastest tectonic area in the world at the junction of the Lau and North-Fiji basins. At this place, the unstable back-arc accommodates the plate motion in three ways: (i) the north Fiji transform fault, (ii) numerous unstable spreading ridges, and (iii) large areas of recent volcanic activity. This instability creates bountiful opportunity for hydrothermal discharge to occur. Based on geochemical (CH4, TDM, 3He) and geophysical (nephelometry) tracer surveys: (1) no hydrothermal activity could be found on the Futuna Spreading Center (FSC) which sets the western limit of hydrothermal activity; (2) four distinct hydrothermal active areas were...
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Ano: 2016 URL: http://archimer.ifremer.fr/doc/00347/45848/45505.pdf
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Growth and demise of Cenozoic isolated carbonate platforms: New insights from the Mozambique Channel seamounts (SW Indian Ocean) ArchiMer
Courgeon, Simon; Jorry, Stephan; Camoin, G. F.; Boudagher-fadel, M. K.; Jouet, Gwenael; Revillon, Sidonie; Bachelery, P.; Pelleter, Ewan; Borgomano, J.; Poli, E.; Droxler, A. W..
Although long-term evolutions of isolated shallow-water carbonate platforms and demise episodes leading to guyot formation have been the subject of numerous studies during the last decades, their driving processes are still the subject of active debates. The Mozambique Channel (SW Indian Ocean) is characterized by several flat-topped seamounts ranging from 11°S to 21°S in latitudes. Based on a comprehensive geomorphologic study and on dredged samples analysis, we show that these features correspond to tropical isolated shallow-water carbonate platforms. Coupling strontium isotopy and foraminifera biostratigraphy, well-constrained chronostratigraphy results indicate that shallow-water carbonate production started in the Mozambique Channel during distinct...
Tipo: Text Palavras-chave: Carbonate platform; Drowning; Cenozoic; Mozambique Channel; East African rift system.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00347/45827/46634.pdf
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Influence of early diagenesis on geotechnical properties of clay sediments (Romania, Black Sea) ArchiMer
Ballas, Gregory; Garziglia, Sebastien; Sultan, Nabil; Pelleter, Ewan; Toucanne, Samuel; Marsset, Tania; Riboulot, Vincent; Ker, Stephan.
The geotechnical properties of clay sediments were investigated using laboratory and in-situ measurements as part of the geohazard assessment in the Romanian sector of the Black Sea affected by landslides and seafloor deformation features. The sediments were characterized as predominantly high plastic silty clay of high compressibility, low undrained shear strength, low cohesion and moderate sensitivity. A shallow increase in shear strength exceeding the general trend could have been reconciled with evidence for the precipitation of iron sulfides and calcium carbonates related to early diagenetic reactions of sulfate reduction (e.g. cryptic sulfur cycle) and anaerobic oxidation of methane. Comparison of the compression behaviour of natural and...
Tipo: Text Palavras-chave: Lacustrine clay sediment; Structured material; Sulfur cement; Carbonate cement; Early diagenesis; Weak layer.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00439/55064/56545.pdf
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Living (stained) deep-sea foraminifera from the Sea of Marmara: a preliminary study ArchiMer
Fontanier, Christophe; Dissard, D.; Ruffine, Livio; Mamo, B.; Ponzevera, Emmanuel; Pelleter, Ewan; Baudin, F.; Roubi, Angelique; Cheron, Sandrine; Boissier, Audrey; Gayet, Nicolas; Bermell-fleury, S.; Pitel, M.; Guyader, Vivien; Lesongeur, Francoise; Savignac, F..
In this preliminary study, we investigate living (stained) foraminifera from the Sea of Marmara. We focus on the faunal composition and geochemical signatures (trace elements, carbon and oxygen stable isotopes) in foraminiferal tests at two deep-sea sites (329 and ~1240 m depth respectively). Documented by ROV observations and sampling, both study areas are heterogeneous (including bacterial mats and carbonate concretions), proximal to cold seeps and consist of dysoxic bottom water (O2<20 µmol/L). The prevailing dysoxia at both study areas restricts foraminiferal diversity to very low values (S<9, H’<0.97). Stress-tolerant species Bolivina vadescens and Globobulimina affinis dominate living faunas at both sites. The highest foraminiferal standing...
Tipo: Text Palavras-chave: Living (stained) benthic foraminifera; Sea of Marmara; Extreme ecosystems; Trace elements; Stable isotopes.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00416/52774/53646.pdf
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Ni-Cu-Co-rich hydrothermal manganese mineralization in the Wallis and Futuna back-arc environment (SW Pacific) ArchiMer
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
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Organic, Gas, and Element Geochemistry of Hydrothermal Fluids of the Newly Discovered Extensive Hydrothermal Area in the Wallis and Futuna Region (SW Pacific) ArchiMer
Konn, Cecile; Donval, Jean-pierre; Guyader, Vivien; Roussel, Erwan; Fourre, E.; Jean-baptiste, P.; Pelleter, Ewan; Charlou, Jean-luc; Fouquet, Yves.
Two newly discovered hydrothermal vent fields of the Wallis and Futuna region, Kulo Lasi and Fatu Kapa, were sampled for fluid geochemistry. A great geochemical diversity was observed and assigned to the diversity of lithologies as well as the occurrence of various processes. Kulo Lasi fluids likely formed by interaction with fresh volcanic rocks, phase separation, and mixing with magmatic fluid. Conversely, the geochemistry of the Fatu Kapa fluids would be mostly due to water/felsic lavas reactions. In terms of organic geochemistry, fluids from both fields were found to be enriched in formate, acetate, and semivolatile organic compounds (SVOCs): n-alkanes, n-fatty acids, and polyaromatic hydrocarbons (PAHs). Concentrations of SVOCs reached a few ppb at...
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Ano: 2018 URL: https://archimer.ifremer.fr/doc/00431/54245/55571.pdf
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Sulfate minerals control dissolved rare earth element flux and Nd isotope signature of buoyant hydrothermal plume (EMSO-Azores, 37°N Mid-Atlantic Ridge) ArchiMer
Chavagnac, Valerie; Ali, Hassan Saleban; Jeandel, Catherine; Leleu, Thomas; Destrigneville, Christine; Castillo, Alain; Cotte, Laura; Waeles, Mathieu; Cathalot, Cecile; Laes, Agathe; Pelleter, Ewan; Nonnotte, Philippe; Sarradin, Pierre-marie; Cannat, Mathilde.
While hydrothermal vents are now thought to be a major source of dissolved iron to the oceans, they have always been considered to be a sink for the dissolved rare-earth elements (DREEs). However, true dissolved REE observations in hydrothermal plumes are still lacking. Here we report for the first time the DREE concentrations and neodymium isotopic compositions (DεNd) of buoyant hydrothermal fluids at Lucky Strike (Mid-Atlantic Ridge). We find that 27 to 62% of total hydrothermal DREEs are rapidly scavenged by anhydrite precipitation at the onset of buoyant plume formation. After this initial loss, all DREEs behave quasi-conservatively within the buoyant plume. Dissolved phase εNd (DεNd) in the evolving plume are identical to black smoker DεNd of +9.0 and...
Tipo: Text Palavras-chave: Black smokers; Rare earth elements; Neodymium isotopes; Hydrothermal; Sulfate minerals; EMSO-Azores.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00456/56733/58511.pdf
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The Cryogenian arc formation and successive high-K calc-alkaline plutons of Socotra Island (Yemen) ArchiMer
Denele, Y.; Leroy, S.; Pelleter, Ewan; Pik, R.; Talbot, J-y.; Khanbari, K..
The Socotra Island belongs to the southern rifted margin of the Gulf of Aden and occupied in Neoproterozoic times a key position to constrain the age and the nature of the largely hidden Neoproterozoic rocks of the Arabian plate. Our integrated field, petrographic, geochemical and geochronological study in the Neoproterozoic rocks recognises three main successive events: (a) high-temperature ductile deformation and metamorphism forming probably in a compressive or transpressive regime; (b) mafic to intermediate intrusions as vertical sheets, kilometre-scale gabbro laccoliths, mafic dike swarm and lavas which present mainly a depleted arc signature with some evidences of evolution from an enriched-arc signature; (c) felsic intrusions mainly composed of...
Tipo: Text Palavras-chave: Neoproterozoic; East African-Antartic Orogen; Arabian-Nubian shield; Socotra Island; Andean-type arc; Back-arc basin.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00090/20131/17839.pdf
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The dark side of soft tissues: unexpected inorganic carbonate in the invasive slipper limpet Crepidula fornicata and its implications for stable isotope interpretations ArchiMer
Androuin, Thibault; Dubois, Stanislas; Decottignies, Priscilla; Pelleter, Ewan; Carlier, Antoine.
Rationale Stable isotopic analysis is extensively used in trophic ecology. Inorganic carbonates, usually originating from shell fragments, are routinely removed from samples using an acid treatment because they affect δ13C values. However, acid treatment can also change δ15N values. For some taxa such as molluscs, the general assumption is that acid pre‐treatment is not necessary since their shell is easily dissected from soft tissues and represents the only source of inorganic carbonates. However, other sources of non‐dietary carbon (e.g., intracellular inorganic carbon) enriched in 13C thus get overlooked. Methods Soft tissues (foot) of the invasive gastropod Crepidula fornicata of different size classes were analysed for their δ13C and δ15N values with...
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Ano: 2019 URL: https://archimer.ifremer.fr/doc/00464/57602/59798.pdf
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Volcanic and hydrothermal processes in submarine calderas: the Kulo Lasi example (SW Pacific) ArchiMer
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
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Young Marquesas volcanism finally located ArchiMer
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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