9 results on '"T. Augé"'
Search Results
2. A stable isotopic study of the Bruvann Ni deposit, Norway
- Author
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C. Lerouge, T. Augé, P. Lamberg, and F. Pineau
- Published
- 2022
3. Origin of chromite in mafic–ultramafic-hosted hydrothermal massive sulfides from the Main Uralian Fault, South Urals, Russia
- Author
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V. V. Zaykov, Svetlana G. Tesalina, Paolo Nimis, and T Augé
- Subjects
Peridotite ,education.field_of_study ,Volcanogenic massive sulfide ore deposit ,Population ,Geochemistry ,Geology ,Geochemistry and Petrology ,Ultramafic rock ,Chromite ,Mafic ,education ,Forearc ,Melt inclusions - Abstract
Mafic–ultramafic-hosted hydrothermal Fe–Cu–(Ni–Co) sulfide ores from the Main Uralian Fault Zone (MUFZ), South Urals (Ivanovka and Ishkinino ore fields), contain a relatively large (up to 3%) proportion of chromite. This association is common for magmatic Fe–Ni–Cu sulfides, but definitely unusual for hydrothermal sulfides. Textural, morphological and compositional data are used here to gain an insight into the origin and significance of this unusual chromite–sulfide association. The studied chromites occur both as broken fragments and as euhedral or subhedral crystals, which are included in the sulfides or scattered in their talc±chlorite±saponite±quartz±carbonate matrix. They are characterized by high Cr/(Cr+Al) ratios (0.58–0.85) and range in composition from magnesiochromite to chromite sensu stricto. Textural, morphological and compositional features, as well as the occurrence of relatively high-silica, low-Ti, low-K melt inclusions in some of the crystals, indicate that the ore-associated chromites (i) are a mixed population of grains derived from mafic–ultramafic mantle and crustal magmatic rocks and mantle peridotite melting residua, (ii) have no genetic relation with the host sulfides and (iii) represent relicts derived from the hydrothermally altered country rocks. The compositions of the chromites and of the melt inclusions denote a clear supra-subduction zone signature. The melts parent to the cumulitic chromites had an arc tholeiitic to, possibly, boninitic affinity. These data suggest that the host mafic–ultramafic complexes formed in an early arc or forearc setting and do not represent obducted portions of MORB oceanic lithosphere. Hence, contrary to previous interpretations, the associated massive sulfides could not originate on a mid-ocean ridge, but rather in an early arc or forearc environment. Given the relatively short life of the western Uralian arc system, the most probable time window for sulfide ore deposition is confined to Early to Middle Devonian time.
- Published
- 2003
4. Existence of two widespread semi-isolated genetic entities within Mediterranean anchovies
- Author
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K. Fadhlaoui-Zid, S. Oueslati, M. T. Augé, François Bonhomme, Jean-Pierre Quignard, O. Kada, Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UR226, Institut National des Sciences et Technologie de la Mer, Institut National des Sciences et Technologies de la Mer [Salammbô] (INSTM), and Institut National Agronomique de Tunisie
- Subjects
Mediterranean climate ,[SDV.GEN]Life Sciences [q-bio]/Genetics ,Ecology ,biology ,[SDV]Life Sciences [q-bio] ,Disequilibrium ,Aquatic Science ,biology.organism_classification ,Anchovy ,medicine ,Microsatellite ,Black sea ,14. Life underwater ,medicine.symptom ,Ecology, Evolution, Behavior and Systematics - Abstract
International audience; We investigated genetic transitions in European anchovies (Engraulidae) by analysing one mitochondrial and six nuclear microsatellite loci in samples from 28 geographical locations, primarily in the Western Mediterranean with external samples from the Black Sea in the East, and the Gulf of Biscay in the West. Four samples were collected from lagoons or shallow waters in France, Morocco and Tunisia. Two strongly differentiated loci and nucleo-cytoplasmic disequilibrium allowed us unambiguously to confirm the existence of a coastal genetic entity that is distinct from the more offshore marine populations. By contrast, four microsatellites were undifferentiated within the entire set of samples, testifying to a variable permeability of the two interacting genomes. Our findings strengthen and extend previous reports of the existence of a coastal anchovy entity that is widespread in Mediterranean lagoons.
- Published
- 2014
5. Bioleaching of an organic-rich polymetallic concentrate using stirred-tank technology
- Author
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Patrick d'Hugues, Jérôme Gouin, P. Spolaore, Dominique Morin, A. Ibáñez, T. Augé, Catherine Joulian, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Hydrometallurgy and Electrochemistry, and Tecnicas Reunidas
- Subjects
Silver ,Continuous operation ,0211 other engineering and technologies ,Continuous stirred-tank reactor ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Industrial and Manufacturing Engineering ,Brine leaching ,Black shale concentrate ,Bioleaching ,Stirred-tank reactor ,Materials Chemistry ,[SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering ,021102 mining & metallurgy ,0105 earth and related environmental sciences ,Hydrometallurgy ,Chemistry ,Chalcopyrite ,Metallurgy ,Metals and Alloys ,Ore concentrate ,Pulp and paper industry ,visual_art ,visual_art.visual_art_medium ,Leaching (metallurgy) ,Aeration ,Copper ,Moderate thermophiles - Abstract
International audience; The bioleaching of a concentrate produced from a black shale ore in an industrial operation in Poland was assessed. Following preliminary batch culture tests, processing in continuous conditions was tested to determine the main specifications for the application of the stirred-tank technology to this organic-rich polymetallic concentrate. The experimental work was carried out in a laboratory-scale unit consisting of three stirred tanks (50 L or 20 L) using an acidophilic and moderate thermophilic (42 °C) bacterial population. Different configurations of the unit and key operating parameters were tested (nutrient medium composition, solids concentration, agitation and aeration rates). The analysis of both bacterial community structure and mineralogical characteristics of the concentrate and the bioleach residues were implemented in order to better understand the chemical and biochemical reactions occurring in the system. Using the data produced during the continuous operation, downstream processing assessment for both copper and silver recovery was also carried out. The best copper recovery obtained in the continuous operation was 92% and hot brine leaching of the bioleaching residue (PLINT Process) permitted the recovery of 92% of the silver. Copper and silver recoveries seemed to be limited by incomplete chalcopyrite dissolution. A preliminary techno-economical evaluation of the concentrate bioleach processing, including bioleaching and copper and silver recoveries, demonstrated the potential economical feasibility. Silver recovery plays an important role in the process's finances. This study presents promising results that encourage further investigation of bioleach processing.
- Published
- 2009
6. Crack path in liquid metal embrittlement: experiments with steels and modeling
- Author
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T. Auger, S. Hémery, M. Bourcier, C. Berdin, M. Martin, and I. Robertson
- Subjects
Crack path ,Liquid Metal Embrittlement ,Steels ,Multi-scale crack propagation modelling ,Mechanical engineering and machinery ,TJ1-1570 ,Structural engineering (General) ,TA630-695 - Abstract
We review the recent experimental clarification of the fracture path in Liquid Metal Embrittlement with austenitic and martensitic steels. Using state of the art characterization tools (Focused Ion Beam and Transmission Electron Microscopy) a clear understanding of crack path is emerging for these systems where a classical fractographic analysis fails to provide useful information. The main finding is that most of the cracking process takes place at grain boundaries, lath or mechanical twin boundaries while cleavage or plastic flow localization is rarely the observed fracture mode. Based on these experimental insights, we sketch an on-going modeling strategy for LME crack initiation and propagation at mesoscopic scale. At the microstructural scale, crystal plasticity constitutive equations are used to model the plastic deformation in metals and alloys. The microstructure used is either extracted from experimental measurements by 3D-EBSD (Electron Back Scattering Diffraction) or simulated starting from a Voronoï approach. The presence of a crackwithin the polycrystalline aggregate is taken into account in order to study the surrounding plastic dissipation and the crack path. One key piece of information that can be extracted is the typical order of magnitude of the stress-strain state at GB in order to constrain crack initiation models. The challenges of building predictive LME cracking models are outlined.
- Published
- 2016
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7. Crack path in liquid metal embrittlement: experiments with steels and modeling
- Author
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T. Auger, S. Hémery, M. Bourcier, C. Berdin, M. Martin, and I. Robertson
- Subjects
Crack path ,Liquid Metal Embrittlement ,Steels ,Multi-scale crack propagation modelling ,Mechanical engineering and machinery ,TJ1-1570 ,Structural engineering (General) ,TA630-695 - Abstract
We review the recent experimental clarification of the fracture path in Liquid Metal Embrittlement with austenitic and martensitic steels. Using state of the art characterization tools (Focused Ion Beam and Transmission Electron Microscopy) a clear understanding of crack path is emerging for these systems where a classical fractographic analysis fails to provide useful information. The main finding is that most of the cracking process takes place at grain boundaries, lath or mechanical twin boundaries while cleavage or plastic flow localization is rarely the observed fracture mode. Based on these experimental insights, we sketch an on-going modeling strategy for LME crack initiation and propagation at mesoscopic scale.
- Published
- 2015
8. Comparative Study of Chromite Deposits from Troodos, Vourinos, North Oman and New Caledonia Ophiolites
- Author
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T. Augé and Z. Johan
- Subjects
geography ,Olivine ,geography.geographical_feature_category ,Laurite ,Pargasite ,Geochemistry ,Massif ,engineering.material ,Mining engineering ,engineering ,Plagioclase ,Chromitite ,Chromite ,Amphibole ,Geology - Abstract
The comparative study of chromitites from Vourinos (Greece), Troodos (Cyprus), Semail (Oman), Tiebaghi and Massif du Sud (New Caledonia) ophiolitic complexes reveals that all studied chromite deposits are surrounded by dunite whose extent bears no relation to the size of the orebody. The dunite-chromitite contact may be gradational or sharp; in Oman, its sharpness is emphasized by the presence of interstitial silicates (plagioclase, pyroxenes) in chromitite which are missing in the surrounding dunite. The occurrence of PGM inclusions in disseminated chromite from dunite in the Vourinos and Tiebaghi ophiolites infers a genetic relationship between chromitites and their dunitic envelopes. In chromite deposits from Vourinos and Massif du Sud, olivine is the only interstitial phase. The Oman chromitites exhibit a complex interstitial assemblage with olivine, clinopyroxene, plagioclase and pargasitic amphibole. Silicate inclusions (olivine, orthopyroxene, clinopyroxene, plagioclase, pargasite, phlogopite, sodium equivalent of phlogopite, nepheline) are commonly observed in chromitites. Their distribution within the host crystal indicates that they were trapped during chromite crystallization. Tabular crystals of both pyroxenes found in some chromite bodies might result from epitaxial intergrowth or from exsolution.
- Published
- 1988
9. Solubilité des éléments du groupe du platine (PT ET PD) dans les liquides silicatés en fonction de FO 2, FS 2, T, P et composition : expérimentation, modélisation , implications métallogéniques et Géochimiques
- Author
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Azif, Ettibari, Centre de Recherche sur la Synthèse et la Chimie des Minéraux (CRSCM), Centre National de la Recherche Scientifique (CNRS), Université d'Orléans, Michel Pichavant, T. Augé(pichavan@cnrs-orleans.fr), and POTHIER, Nathalie
- Subjects
[SDU.STU.AG] Sciences of the Universe [physics]/Earth Sciences/Applied geology ,ETUDE EXPERIMENTALE/SOLUBILITE/ELEMENT GROUPE PLATINE/PLATINE/PALLADIUM/LIQUIDE SILICATE/FUGACITE/OXYGENE/SOUFRE/CONDITION PRESSION TEMPERATURE/MODELE/METALLOGENIE/ALLIAGE/SPECTROMETRIE MASSE/PLASMA COUPLE INDUCTIVEMENT/SPECIATION/COEFFICIENT PARTAGE/SPECTROMETRIE ICP/PETROLOGIE EXPERIMENTALE ,[SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology - Abstract
L'ETUDE EXPERIMENTALE A DEMONTRE (1) L'INFLUENCE IMPORTANTE DE CERTAINS PARAMETRES (FO2, COMPOSITION DE L'ALLIAGE METALLIQUE, FS2) SUR LA SOLUBILITE DES EGP DANS LES LIQUIDES BASALTIQUES ET (2) LE ROLE SENSIBLEMENT MOINS IMPORTANT D'AUTRES PARAMETRES (T, COMPOSITION DU LIQUIDE SILICATE). A 1 ATM, 1300< T, Pas de résumé
- Published
- 1998
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