Papers by Elena Bazarkina
The distribution of heat-producing trace elements including uranium (U) and thorium (Th) between ... more The distribution of heat-producing trace elements including uranium (U) and thorium (Th) between a silicate and metal melt is a key parameter to reconstruct the formation history of the Earth's core, its composition and initial heat budget. The main objective of this study is to unambiguously investigate the valance of U and Th contained in silicate glasses (600 ppm) synthesized previously at Early Earth's conditions (highly reducing). This knowledge is crucial to interpret their experimentally observed silicate-metal melt distribution behaviors and to deduce their abundances in the Earth's core. U and Th valence can only be determined unambiguously from High-energy-resolution-fluorescence (HERFD) X-ray Near Edge Absorption Spectroscopy measurements at the M4 edges, which remain challenging at these high dilution levels. ID26 and BM20 are the few instruments in Europe allowing acquiring such data also thanks to the significant flux increase of the ESRF-EBS.
Elements
The presence of H2 and H2O in planetary interiors prompts the need for fundamental studies on the... more The presence of H2 and H2O in planetary interiors prompts the need for fundamental studies on these compounds under corresponding conditions. Here, we summarize data on H2 properties in aqueous systems under conditions of high temperature and pressure. We explain how to measure important H2 fugacities in hydrothermal systems. We present available experimental data and thermodynamic models for H2 solubility and vapor–liquid partitioning under hydrothermal conditions. In addition, we introduce the fascinating world of H2–H2O clathrate hydrates under extreme temperatures and pressures. The properties of the H2–H2O system are well established below the critical point of water (374 °C and 22.06 MPa), but far less is known under higher temperatures and pressures, or the effect of salt.
Geology of Ore Deposits, 2010
Potentiometric measurements were performed in the Cd(NO 3) 2-KCl-H 2 O system at 25°C and 1-1000 ... more Potentiometric measurements were performed in the Cd(NO 3) 2-KCl-H 2 O system at 25°C and 1-1000 bar using an isothermal cell with a liquid junction and equipped with a solid contact Cd selective electrode. At 1 bar, the stepwise equilibrium constant of the fourth cadmium chloride complex has been determined (log =-0.88 ± 0.25). The pressure dependent stability constants for all cadmium chlo ride complexes have been experimentally established for the first time. As pressure increases from 1 to 1000 bar, the stability constants for the first, third, and fourth complexes change by less than 0.05 logarithmic units, whereas that for the second complex decreases by 0.33 logarithmic units. On the basis of these data, the partial molar volumes of four cadmium chloride complexes have been determined under standard state con ditions: V 0 (CdCl +) = 2.20 ± 3, V 0 (CdCl 2 (aq)) = 42.21 ± 5, V 0 () = 63.47 ± 10, and V 0 () = 81.35 ± 15 cm 3 mol-1. The linear correlation between the nonsolvation contributions of molar volumes and the number of ligands corresponds to the change in coordination from octahedral in Cd 2+ and CdCl + to tet rahedral in CdCl 2 (aq) , , and complexes. Using theoretical correlations, the HKF parameters allowing calculation of the volumetric properties of cadmium chloride complexes in a wide range of temper ature and pressure have been obtained. The pressure effect on cadmium concentration in sphalerite in equi librium with the H 2 O-NaCl hydrothermal fluid has been estimated. It is shown that the Cd content in sphalerite increases with pressure.
American Mineralogist, 2021
9 Experimental Geosciences Group (GeoExp), Géosciences Environnement Toulouse (GET), UMR 10 5563,... more 9 Experimental Geosciences Group (GeoExp), Géosciences Environnement Toulouse (GET), UMR 10 5563, Observatoire Midi-Pyrénées, Université de Toulouse, Centre National de la Recherche 11 Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), 14, avenue Edouard Belin, 12 F-31400 Toulouse, France 13 PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne 14 Université, CNRS, F-75005 Paris, France 15 Université Grenoble Alpes, CNRS, Institut Néel, 25, avenue des Martyrs, F-38042 Grenoble Cedex 16 9, France 17 Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, Russian 18 Academy of Sciences (IGEM RAS), 35, Staromonetny per., F-119017 Moscow, Russia 19 Sorbonne Université, CNRS, UMR 7590, IMPMC, F-75005 Paris, France 20 21 22 23 * Corresponding author: phone: (33)-(0)5-61-33-26-18; fax: (33)-(0)5-61-33-25-60; 24 e-mail: [email protected]; [email protected] 25 26 27 28 Revision 1 for American Mineralogist 29
Olivier Proux, Eric Lahera, William Del Net, Isabelle Kieffer, Mauro Rovezzi, Denis Testemale, Mo... more Olivier Proux, Eric Lahera, William Del Net, Isabelle Kieffer, Mauro Rovezzi, Denis Testemale, Mohammed Irar, Sara Thomas, Antonio Aguilar-Tapia, Elena F. Bazarkina, Alain Prat, Marie Tella, Mélanie Auffan, Jérôme Rose, Jean-Louis Hazemann 1 Observatoire des Sciences de l'Univers de Grenoble (OSUG), UMS 832 CNRS Univ. Grenoble Alpes, F38041 Grenoble, France 2 Inst. Néel, UPR 2940 CNRS Univ. Grenoble Alpes, F-38000 Grenoble, France 3 Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208, United States 4 Laboratoire de Chimie et Biologie des Métaux (LCBM) UMR 5249 CNRS CEAUniv. Grenoble Alpes, F38054 Grenoble, France 5 Institute of Geology of Ore Deposits, Mineralogy, Petrography and Geochemistry, Russian Academy of Sciences, IGEM RAS, 119017 Moscow, Russia 6 Centre de coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), US 49 Analyse, TA B-49/01, F-34398 Montpellier Cedex 5, France 7 Centre de Recherche ...
Cette etude a pour but de quantifier le role de la phase fluide et vapeur dans le comportement de... more Cette etude a pour but de quantifier le role de la phase fluide et vapeur dans le comportement de Zn et de Cd dans les processus hydrothermaux/volcaniques, en combinant mesures experimentales en laboratoire (solubilite, potentiometrie, coefficients de partage) et spectroscopie d'absorption de rayons X in situ (XAS) avec modelisations physico-chimiques et analyses de gaz volcaniques naturels. Nos resultats mettent en evidence la formation de complexes chlorures en phase fluide et vapeur de stoechiometrie CdClm(H2O)n2-m ayant des geometries octaedrique ou tetraedrique selon T et mCl. Les parametres thermodynamiques generes pour ces complexes demontrent qu'ils sont les especes majeures responsables du transport de Cd par les fluides naturels. Ces complexes chlorures de Cd sont beaucoup plus stables que leurs analogues de Zn et jouent un role cle dans le fractionnement des deux metaux. L'ensemble des donnees experimentales, thermodynamiques et analytiques obtenu permet de pr...
Geochimica et Cosmochimica Acta
Goldschmidt2021 abstracts
Geochimica et Cosmochimica Acta
Goldschmidt2021 abstracts
Proceedings of the National Academy of Sciences
Platinum group elements (PGE) are considered to be very poorly soluble in aqueous fluids in most ... more Platinum group elements (PGE) are considered to be very poorly soluble in aqueous fluids in most natural hydrothermal–magmatic contexts and industrial processes. Here, we combined in situ X-ray absorption spectroscopy and solubility experiments with atomistic and thermodynamic simulations to demonstrate that the trisulfur radical ion S3•− forms very stable and soluble complexes with both PtII and PtIV in sulfur-bearing aqueous solution at elevated temperatures (∼300 °C). These Pt-bearing species enable (re)mobilization, transfer, and focused precipitation of platinum up to 10,000 times more efficiently than any other common inorganic ligand, such as hydroxide, chloride, sulfate, or sulfide. Our results imply a far more important contribution of sulfur-bearing hydrothermal fluids to PGE transfer and accumulation in the Earth’s crust than believed previously. This discovery challenges traditional models of PGE economic concentration from silicate and sulfide melts and provides new pos...
Hydrogen gas is seeping from the sedimentary basin of São Franciso, Brazil. The seepages of H2 ar... more Hydrogen gas is seeping from the sedimentary basin of São Franciso, Brazil. The seepages of H2 are accompanied by helium whose isotopes reveal a strong crustal signature. Geophysical data indicates that this intra-cratonic basin is characterized by i) a relatively high geothermal gradient, ii) deep faults delineating a horst and graben structure and affecting the entire sedimentary sequence, iii) an archean to paleoproterozoïc basements enriched in radiogenic elements and displaying mafic and ultramafic units, and iv) a possible karstic reservoir located 400 m below the surface. The high geothermal gradient could be due to a thin lithosphere enriched in radiogenic elements, which can also contribute to a massive radiolysis process of water at depth, releasing an important amount of H2. Alternatively, ultramafic rocks that may have generated H2 during their serpentinization are also documented in the basement. The seismic profiles show that the faults seen at the surface are deeply r...
Elements
The presence of H2 and H2O in planetary interiors prompts the need for fundamental studies on the... more The presence of H2 and H2O in planetary interiors prompts the need for fundamental studies on these compounds under corresponding conditions. Here, we summarize data on H2 properties in aqueous systems under conditions of high temperature and pressure. We explain how to measure important H2 fugacities in hydrothermal systems. We present available experimental data and thermodynamic models for H2 solubility and vapor–liquid partitioning under hydrothermal conditions. In addition, we introduce the fascinating world of H2–H2O clathrate hydrates under extreme temperatures and pressures. The properties of the H2–H2O system are well established below the critical point of water (374 °C and 22.06 MPa), but far less is known under higher temperatures and pressures, or the effect of salt.
E3S Web of Conferences
This experimental and theoretical study is aimed at better quantifying the transport of Zn and Cd... more This experimental and theoretical study is aimed at better quantifying the transport of Zn and Cd by hydrothermal fluids rich in sulfur by using in-situ X-ray absorption spectroscopy (XAS). We measured simultaneously fluorescence and transmission spectra of dissolved metal in NaHS-H2S, K2S2O3, Na2S2O3, K2S2O3-HCl aqueous solutions at 250-350°C and 600 bar. Here the first experimental results are presented. Possible sulfur speciation models for Zn and Cd are briefly discussed.
E3S Web of Conferences
Much has been learned about natural hydrogen (H2) seepages and accumulation, but present knowledg... more Much has been learned about natural hydrogen (H2) seepages and accumulation, but present knowledge of hydrogen behavior in the crust is so limited that it is not yet possible to consider exploitation of this resources. Hydrogen targeting requires a shift in the long-standing paradigms that drive oil and gas exploration. This paper describes the foundation of an integrated source-to-sink view of the hydrogen cycle, and propose preliminary practical guidelines for hydrogen exploration.
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Papers by Elena Bazarkina