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Lev Filippov - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Weda Bay nickel laterite ore from Indonesia
Journal of Geochemical Exploration, 2019Co-Authors: Saeed Farrokhpay, Michel Cathelineau, Simon Blancher, Odile Laugier, Lev FilippovAbstract:The association of fine grained MgeNi silicates with oxy-hydroxides in laterites and saprolites represents challenges for ore processing, in particular, in nickel enrichment. The Weda Bay nickel deposit in Indonesia is a typical example of these complex ores, where clays such as nontronites develop on polyphase serpentinite as protolith. Thus, ores at Weda Bay have a very fine textured and complex mineralogy, which requires a comprehensive mineralogical identification through the use of a series of different types of analytical approaches (i.e. macroscopic and microscopic methods including SEM equipped with energy dispersive X-ray spectrometry (EDS), Raman spectroscopy, Infrared and X-ray fluorescence spectroscopy, and QEMSCAN® mapping). Nickel rich saprolites were found to be principally composed of several types of MgeNi Serpentines, quartz, clays (nontronite in particular) and little amounts of iron hydroxides. Besides, some parts of the deposit were characterized by the development of nontronites at the interface between the saprolite and the limonite zone. Above this zone, the limonite zone is dominated by iron hydroxides as expected, which replace all earlier silicates including Serpentine, and contains a significant amount of nickel. The representative composite ore sample contains several nickel bearers with variable nickel grade of 2 to 3%. Exceptionally richer phases such as polygonal Fe (Ni)-rich Serpentine were also found with nickel grade of 5 to 10%. Serpentine types as well as other newly formed silicates such as Fe-Mg-(Ni) smectites, are intimately mixed, preventing any mineral separation. Therefore, the only phases which can be separated are quartz and magnetite. This complicates the upgrading of nickel in Weda Bay laterite ore.
Bruno Reynard - One of the best experts on this subject based on the ideXlab platform.
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Serpentines, talc, chlorites, and their high-pressure phase transitions: a Raman spectroscopic study
Physics and Chemistry of Minerals, 2015Co-Authors: Bruno Reynard, Lucile Bezacier, Razvan CaracasAbstract:Raman spectra of magnesian phyllosilicates belonging to the Serpentine, talc, and chlorite groups have been obtained at ambient conditions, and at high pressures and up to 200 °C in order to study high-pressure transformations in the 10 GPa range. The complex and distinct Raman spectra of these minerals allow straightforward identification, which may otherwise be difficult from optical microscopy. High-pressure measurements are in good agreement with DFT calculations for talc and lizardite. Pressure-induced displacive modifications are identified in lizardite and antigorite Serpentines, and in chlorite at ~4, 7 and 8 GPa, respectively, while talc shows no transition up to ~11 GPa. At high temperature, the high-pressure distortions of Serpentines shift to higher pressures. Given the stability limits of these minerals, and the natural range of P–T conditions, none of the high-pressure distortions observed at high pressure are likely to occur at depth in the Earth.
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Serpentines, talc, chlorites, and their high-pressure phase transitions: a Raman spectroscopic study
Physics and Chemistry of Minerals, 2015Co-Authors: Bruno Reynard, Lucile Bezacier, Razvan CaracasAbstract:Raman spectra of magnesian phyllosilicates belonging to the Serpentine, talc, and chlorite groups have been obtained at ambient conditions, and at high pressures and up to 200 °C in order to study high-pressure transformations in the 10 GPa range. The complex and distinct Raman spectra of these minerals allow straightforward identification, which may otherwise be difficult from optical microscopy. High-pressure measurements are in good agreement with DFT calculations for talc and lizardite. Pressure-induced displacive modifications are identified in lizardite and antigorite Serpentines, and in chlorite at ~4, 7 and 8 GPa, respectively, while talc shows no transition up to ~11 GPa. At high temperature, the high-pressure distortions of Serpentines shift to higher pressures. Given the stability limits of these minerals, and the natural range of P–T conditions, none of the high-pressure distortions observed at high pressure are likely to occur at depth in the Earth.
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Serpentine in active subduction zones
Lithos, 2013Co-Authors: Bruno ReynardAbstract:Abstract Serpentinization is a key phenomenon for understanding the geodynamics of subduction zones in the 10–200 km depth range. Serpentines are a major water carrier, and their rheological properties have a strong influence on deformation partitioning and seismicity at depths. I review experimental investigations that have been conducted on Serpentines, with emphasis on the large body of data acquired over the past decade. Determinations of physical properties at the pressure and temperature conditions of subductions allow interpreting geophysical data in active subduction in terms of mineralogy and petrology, and to link the presence of serpentinites with deformation and fluid circulation. The fluid budget can be partially constrained from geophysical data. Elasticity data provide a quantitative basis for mapping serpentinization in the mantle wedge and slab from seismic tomography. Anisotropy suggests the existence of thin serpentinite channels above the plate interface, that account for mechanical decoupling inferred from down-dip limit of the seismogenic zone and heat flow. Strain-rate dependent rheology of antigorite Serpentine is consistent with stable deformation of this thin layer or channel over timescales ranging from those of the seismic cycle to those of thermal equilibration and exhumation of high-pressure rocks, and with the geological record of subduction-related deformation. Circulation of serpentinizing fluids depends on the permeability structure, and is imaged by electrical conductivity tomography. It could be controlled by fracturing in the undeformed cold nose of the mantle wedge, and by plastic deformation along the plate interface. Fluid migration mechanisms are similar to those inferred from petrological and geochemical data on exhumed serpentinites. Estimation of the fluid budget associated with Serpentine formation will rely on numerical simulations for which coupling of kinetics of hydration and dehydration at scales ranging from grain size up to faulting pattern needs to be established, especially for water cycling to the transition zone in the core of the slab.
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Electron back-scattering diffraction (EBSD) measurements of antigorite lattice-preferred orientations (LPO)
Journal of Microscopy, 2010Co-Authors: Bertrand Van De Moortèle, Lucile Bezacier, G. Trullenque, Bruno ReynardAbstract:Lattice preferred orientations of Serpentines induce a strong anisotropy of various properties in Serpentine bearing-rocks. Lattice preferred orientations had so far been obtained only by X-ray diffraction techniques. We have applied electron back-scattering diffraction to the measurement of the lattice preferred orientations of antigorite in a naturally deformed high-pressure serpentinite. This technique is very sensitive to sample preparation that can lead to surface amorphization in the case of Serpentine. A polishing procedure is described that avoids amorphization and allows accurate electron back-scattering diffraction measurements with optimized experimental conditions in a variable pressure scanning electron microscope. Results indicate that deformation leads to lattice preferred orientations characterized by extremely strong c-axis clustering perpendicular to the foliation, as expected for a layered silicate. In the foliation plane, a significant clustering of the a-axis is observed and tentatively attributed to intracrystalline deformation mechanisms. These data suggest that antigorite deforms mostly by gliding along the basal plane of the layered phyllosilicate structure, but that gliding may occur along directions favouring a-axis alignment. Electron back-scattering diffraction appears to be a reliable method for determining phyllosilicate lattice preferred orientations in deformed rocks, with potential applications for determining anisotropy of properties like seismic velocities or thermal and electrical conductivities.
Michel Cathelineau - One of the best experts on this subject based on the ideXlab platform.
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serpentinization of new caledonia peridotites from depth to sub surface
Contributions to Mineralogy and Petrology, 2020Co-Authors: Marc Ulrich, Stéphane Guillot, Manuel Muñoz, Philippe Boulvais, Michel Cathelineau, Dominique Cluzel, Christian PicardAbstract:Serpentinization processes occur at geological settings notably during oceanic subduction and obduction, where mantle rocks interact with water. Different types of Serpentine minerals form according to temperature and pressure conditions, and potentially chemical exchanges. Therefore, the characterization of Serpentine minerals, and the possible occurrence of multiple Serpentine generations in mantle rocks provide essential constraints on the conditions of fluid–rock interactions in the mantle. The serpentinite sole of the Peridotite Nappe of New Caledonia (Southwest Pacific) is the result of several superimposed serpentinisation events. The latter were discriminated using mineralogical and geochemical approaches and modeling. Lizardite represents more than 80% of the entire Serpentine content of the ophiolite. It is crosscut by several veins of other Serpentine species in the serpentinite sole. The relative chronology appears as follows: lizardite 1 → lizardite 2 → antigorite → chrysotile → polygonal Serpentine. The transition from primary/magmatic minerals to lizardite 1 is almost isochemical. Then, the development of lizardite 2 yields an enrichment in fluid-mobile elements such as Cs, Rb, Ba, U and light rare-earth elements and an apparent increase of the Fe3+/FeT ratio. The modeling of δ18O values (1.9–13.9‰) and δD values (88–106‰) of all Serpentine species through Monte-Carlo simulations show that New Caledonia Serpentines were mainly formed in equilibrium with fluids released by the dehydration of altered oceanic crust (AOC) during subduction between 250 and 350 °C. AOC-derived fluids are not the unique source of fluids since a low temperature (100–150 °C) meteoric component is also predicted by the models. Thus, Serpentine acts as a tape-recorder of fluid–rock interactions into the mantle from depth to (sub-)surface.
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Serpentinization of New Caledonia peridotites: from depth to (sub-)surface
Contributions to Mineralogy and Petrology, 2020Co-Authors: Marc Ulrich, Stéphane Guillot, Manuel Muñoz, Philippe Boulvais, Michel Cathelineau, Dominique Cluzel, Christian PicardAbstract:Serpentinization processes occur at geological settings notably during oceanic subduction and obduction, where mantle rocks interact with water. Different types of Serpentine minerals form according to temperature and pressure conditions, and potentially chemical exchanges. Therefore, the characterization of Serpentine minerals, and the possible occurrence of multiple Serpentine generations in mantle rocks provide essential constraints on the conditions of fluid-rock interactions in the mantle. The serpentinite sole of the Peridotite Nappe of New Caledonia (Southwest Pacific) is the result of several superimposed serpentinisation events. The latter were discriminated using mineralogical and geochemical approaches and modeling.Lizardite represents more than 80% of the entire Serpentine content of the ophiolite. It is crosscut by several veins of other Serpentine species in the serpentinite sole. The relative chronology appears as follows: lizardite 1 → lizardite 2 → antigorite → chrysotile → polygonal Serpentine. The transition from primary/magmatic minerals to lizardite 1 is almost isochemical. Then, the development of lizardite 2 yields an enrichment in fluid-mobile elements such as Cs, Rb, Ba, U and light rare-earth elements and an apparent increase of the Fe3+/FeT ratio. The modeling of δ18O values (1.9‰ to 13.9‰) and δD values (88‰ to 106‰) of all Serpentine species through Monte-Carlo simulations show that New Caledonia Serpentines were mainly formed in equilibrium with fluids released by the dehydration of altered oceanic crust (AOC) during subduction between 250°C and 350°C. AOC-derived fluids are not the unique source of fluids since a low temperature (100-150°C) meteoric component is also predicted by the models. Thus, Serpentine acts as
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Characterization of Weda Bay nickel laterite ore from Indonesia
Journal of Geochemical Exploration, 2019Co-Authors: Saeed Farrokhpay, Michel Cathelineau, Simon Blancher, Odile Laugier, Lev FilippovAbstract:The association of fine grained MgeNi silicates with oxy-hydroxides in laterites and saprolites represents challenges for ore processing, in particular, in nickel enrichment. The Weda Bay nickel deposit in Indonesia is a typical example of these complex ores, where clays such as nontronites develop on polyphase serpentinite as protolith. Thus, ores at Weda Bay have a very fine textured and complex mineralogy, which requires a comprehensive mineralogical identification through the use of a series of different types of analytical approaches (i.e. macroscopic and microscopic methods including SEM equipped with energy dispersive X-ray spectrometry (EDS), Raman spectroscopy, Infrared and X-ray fluorescence spectroscopy, and QEMSCAN® mapping). Nickel rich saprolites were found to be principally composed of several types of MgeNi Serpentines, quartz, clays (nontronite in particular) and little amounts of iron hydroxides. Besides, some parts of the deposit were characterized by the development of nontronites at the interface between the saprolite and the limonite zone. Above this zone, the limonite zone is dominated by iron hydroxides as expected, which replace all earlier silicates including Serpentine, and contains a significant amount of nickel. The representative composite ore sample contains several nickel bearers with variable nickel grade of 2 to 3%. Exceptionally richer phases such as polygonal Fe (Ni)-rich Serpentine were also found with nickel grade of 5 to 10%. Serpentine types as well as other newly formed silicates such as Fe-Mg-(Ni) smectites, are intimately mixed, preventing any mineral separation. Therefore, the only phases which can be separated are quartz and magnetite. This complicates the upgrading of nickel in Weda Bay laterite ore.
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Geochemistry of the New Caledonia Serpentinites: Evidences for Multiple Serpentinization Events at Various Depths
2016Co-Authors: Marc Ulrich, Manuel Muñoz, Philippe Boulvais, Michel Cathelineau, Christian Picard, Benita PutlitzAbstract:Studies of Serpentine minerals around the world have shown that different varieties can coexist depending on external conditions such as temperature, pressure and chemical exchanges. Identifying Serpentine variety can thus provide significant constraints on the geodynamic environment at the time of formation. In the New Caledonia (NC) ophiolite, serpentinization is ubiquitous (>50%). The base of the ophiolite is made of a thick serpentinite sole that recorded multiple serpentinization events. This study aims at deciphering the nature and the origin of fluids involved in serpentinization processes from the characterization of primary minerals and Serpentine geochemistry, including: in situ major and trace elements and stable oxygen and hydrogen isotopes. Our results show that lizardite is the main mineral species (~80% of the Serpentine). In the serpentinite sole, lizardite is crosscut by multiple Serpentine veins ordered as follow: lizardite 1→lizardite 2→antigorite→chrysotile→polygonal Serpentine. From the trace elements analysis, we demonstrate that the transition from primary minerals to lizardite 1 occurs almost isochemically. However, Serpentine composition in the sole strongly differs from lizardite 1 and show a great enrichment in fluid-mobile elements and an increase of Fe3+/FeT ratio. Stable isotopes show that Serpentines display a wide range in δ18O (1.9-14‰) and a narrow range in δD (88-106‰). These results were then modeled based on Monte-Carlo simulations. Fluids in equilibrium with NC Serpentines define a linear trend that extends from the meteoric water line to an area defined between 3‰ and 8‰ in δ18O and -80‰ and -60‰ in δD. These compositions are consistent with fluids derived from the dehydration of the altered oceanic crust during the subduction in the South Loyalty Basin at temperatures between 250°C and 400°C. No evidence of sedimentary contribution was observed, suggesting that the serpentinization of the NC ophiolite was complete within few million years after the initiation of the subduction. Low δ18O values indicate that the latest generation of Serpentine may derive from the circulation of meteoric fluids at low temperature (
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Geochemistry of the New Caledonia serpentinites; evidence for multiple serpentinization events at various depths.
2016Co-Authors: Marc Ulrich, Stéphane Guillot, Manuel Muñoz, Philippe Boulvais, Michel Cathelineau, Christian PicardAbstract:Studies of Serpentine minerals around the world have shown that different varieties can coexist depending on external conditions such as temperature, pressure and chemical exchanges. Identifying Serpentine variety can thus provide significant constraints on the geodynamic environment at the time of formation. In the New Caledonia (NC) ophiolite, serpentinization is ubiquitous (>50%). The base of the ophiolite is made of a thick serpentinite sole that recorded multiple serpentinization events. This study aims at deciphering the nature and the origin of fluids involved in serpentinization processes from the characterization of primary minerals and Serpentine geochemistry, including: in situ major and trace elements and stable oxygen and hydrogen isotopes. Our results show that lizardite is the main mineral species ( approximately 80% of the Serpentine). In the serpentinite sole, lizardite is crosscut by multiple Serpentine veins ordered as follow: lizardite 1-->lizardite 2-->antigorite-->chrysotile-->polygonal Serpentine. From the trace elements analysis, we demonstrate that the transition from primary minerals to lizardite 1 occurs almost isochemically. However, Serpentine composition in the sole strongly differs from lizardite 1 and show a great enrichment in fluid-mobile elements and an increase of Fe (super 3+) /Fe (sub T) ratio. Stable isotopes show that Serpentines display a wide range in delta (super 18) O (1.9-14 ppm) and a narrow range in delta D (88-106 ppm). These results were then modeled based on Monte-Carlo simulations. Fluids in equilibrium with NC Serpentines define a linear trend that extends from the meteoric water line to an area defined between 3 ppm and 8 ppm in delta (super 18) O and -80 ppm and -60 ppm in delta D. These compositions are consistent with fluids derived from the dehydration of the altered oceanic crust during the subduction in the South Loyalty Basin at temperatures between 250 degrees C and 400 degrees C. No evidence of sedimentary contribution was observed, suggesting that the serpentinization of the NC ophiolite was complete within few million years after the initiation of the subduction. Low delta (super 18) O values indicate that the latest generation of Serpentine may derive from the circulation of meteoric fluids at low temperature (
Taisong Pan - One of the best experts on this subject based on the ideXlab platform.
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experimental and theoretical studies of Serpentine interconnects on ultrathin elastomers for stretchable electronics
Advanced Functional Materials, 2017Co-Authors: Taisong Pan, Matt Pharr, Rui Ning, Zheng Yan, Xue Feng, Yonggang Huang, John A RogersAbstract:Integrating deformable interconnects with inorganic functional materials establishes a path to high-performance stretchable electronics. A number of applications demand that these systems sustain large deformations under repetitive loading. In this manuscript, the influence of the elastomeric substrate on the stretchability of Serpentine interconnects is investigated theoretically and experimentally. Finite element analyses (FEA) reveal a substantial increase in the elastic stretchability with reductions in substrate thickness. Low-cycle fatigue tests confirm this trend by examining the stretch required to form fatigue cracks associated with plastic deformation. To elucidate the mechanics governing this phenomenon, the buckling behaviors of deformed Serpentine interconnects on substrates of various thicknesses are examined. The analytical model and FEA simulations suggest a change in the buckling mode from local wrinkling to global buckling below a critical thickness of the substrate. Scanning electron microscope and 3D optical profiler studies verify this transition in buckling behavior. The global buckling found in thin substrates accommodates large stretching prior to plastic deformation of the Serpentines, thereby drastically enhancing the stretchability of these systems.
Sebastien Maria - One of the best experts on this subject based on the ideXlab platform.
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Microstructured electrodes supported on Serpentine interconnects for stretchable electronics
Apl Materials, 2019Co-Authors: M. Nasreldin, R. Delattre, B. Marchiori, M. Ramuz, J. L. De Bougrenet Tocnaye, T. Djenizian, Sebastien MariaAbstract:In this work, it is reported the fabrication of highly stretchable electrodes on a polydimethylsiloxane substrate. A laser ablation technique is used to design lithium nickel manganese oxide micropillars supported on Serpentine Al interconnects. Morphological, mechanical, and chemical analyses have been investigated by scanning electron microscopy, optical microscopy, and energy dispersive X-Ray spectroscopy. We show that unlike compact and continuous electrode thin-films, vertical micropillar structures supported on Al Serpentines can be stretched up to 70% without structural damage, which opens a new alternative for the fabrication and development of truly stretchable devices such as stretchable micro-batteries. (C) 2019 Author(s).
