159 results on '"Bernard Bourdon"'
Search Results
2. Corrigendum to 'Testing pyroxenite versus peridotite sources for marine basalts using U-series isotopes' [Lithos 332–333 (2019) 226–244]
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Lynne J. Elkins, Bernard Bourdon, and Sarah Lambart
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Geochemistry and Petrology ,Geology - Published
- 2023
3. The Sn isotope composition of chondrites: Implications for volatile element depletion in the Solar System
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Bernard Bourdon, Xueying Wang, Kevin Righter, Caroline Fitoussi, Quentin Amet, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Murchison meteorite ,Condensation ,Evaporation ,Trace element ,Analytical chemistry ,Volatile elements ,Silicate ,Parent body ,Ordinary chondrites ,chemistry.chemical_compound ,Isotope fractionation ,Allende meteorite ,chemistry ,Meteorite ,[SDU]Sciences of the Universe [physics] ,Geochemistry and Petrology ,Chondrite ,Sn isotopes ,Carbonaceous chondrites - Abstract
International audience; The origin of volatile element depletion in terrestrial planets and meteorites relative to a solar composition represented by CI carbonaceous chondrites remains an unsolved problem. The isotope compositions of moderately volatile elements may offer the possibility to distinguish between the various processes that may have caused this depletion (e.g., partial condensation or partial evaporation). We report high precision Sn isotope measurements in carbonaceous chondrites and ordinary chondrites and the results are reported as δ124/116Sn. Four carbonaceous chondrites (Orgueil CI, Murchison CM2, NWA 5240 CV3 and Allende CV3) show a limited range in δ124/116Sn (-0.02‰ to 0.11‰) with an average value of 0.04 ± 0.11‰ (2 s.d.) for a wide range of Sn concentrations (0.63 ppm to 1.57 ppm). The absence of Sn isotope fractionation among carbonaceous chondrites suggests that volatile depletion may have taken place under thermodynamic equilibrium conditions between solid and vapor in the Solar Nebula. Alternatively, the mixing of two components, a volatile-free component containing no or little Sn and a volatile-rich component could explain this trend. This latter hypothesis is consistent with the overall trace element pattern found in carbonaceous chondrites, showing a constant relative abundance when normalized to CI chondrites for the most volatile elements. In contrast with carbonaceous chondrites, ordinary chondrites exhibit a larger range of Sn isotope compositions (δ124/116Sn from -2.02‰ to 0.64‰), but neither the degree of metamorphism (3-6) nor the group (H, L, LL) is correlated with Sn isotopic variations, or with the Sn contents (range 0.20 to 1.44 ppm). Nineteen out of twenty-one ordinary chondrites are enriched in light Sn isotopes compared with carbonaceous chondrites and the bulk silicate Earth. The trace element patterns of volatile elements in ordinary chondrites suggest that equilibrated ordinary chondrites have been disturbed by parent body processes related to metamorphic or shock overprinting but also inherited isotope fractionation found in unequilibrated ordinary chondrites. Last, the isotope composition of the bulk silicate Earth (BSE) indicates that the volatile element depletion observed in the Earth took place in conditions perhaps similar to those of carbonaceous chondrites, as a simple model describing the effect of Earth's core formation on Sn isotopes shows that the Sn isotope composition of the bulk Earth is identical to that of the BSE and of carbonaceous chondrites.
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- 2021
4. Silicon isotope composition of angrites inherited from early condensation in the protoplanetary disk
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Delphine Losno, Bernard Bourdon, and Caroline Fitoussi
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- 2022
5. Condensation of the precursory elements of xenon isotopes produced by underground nuclear explosions
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Bernard Bourdon and Eric Pili
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- 2022
6. Thermodynamic Determination of Condensation Behavior for the Precursory Elements of Radioxenon Following an Underground Nuclear Explosion
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Bernard Bourdon and Eric Pili
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History ,Polymers and Plastics ,Health, Toxicology and Mutagenesis ,Environmental Chemistry ,General Medicine ,Business and International Management ,Pollution ,Waste Management and Disposal ,Industrial and Manufacturing Engineering - Published
- 2022
7. Trace element volatility and the conditions of liquid-vapor separation in the proto-lunar disk
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Dmitry Ivanov, Caroline Fitoussi, Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology ,Condensation ,Space and Planetary Science ,Astronomy and Astrophysics ,Giant impact ,Moon ,Protolunar disk ,Volatile trace elements - Abstract
International audience; The Moon is thought to have formed from material ejected by a giant impact that took place at the end of Earth's accretion. The material ejected to space generated a large hot structure where material beyond the Roche limit accreted to form the Moon. It has long been known that the Moon is characterized by abundances in moderately volatile elements (MVE) lower than that of the Earth, while more recent studies have established that the concentrations in refractory elements are similar to the bulk Silicate Earth. The thermodynamic conditions that prevailed after this impact are poorly known and understanding the origin of the Moon-Earth differences in MVE requires a knowledge of the volatility of elements under these conditions. In this study, we reexamine the volatility of a large set of geochemically relevant elements and attempt to determine the P-T conditions under which volatiles were putatively separated from the liquid material. Our model predicts very different condensation temperatures due to higher pressures, compared with the conditions of the Solar Nebula and we extend the values of these temperatures to a wide number of trace elements
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- 2022
8. Determination of chromium isotopic composition in various geological material by thermal ionization mass spectrometry
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Mélie Cornet, Caroline Fitoussi, Bernard Bourdon, Eric Pili, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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[SDU]Sciences of the Universe [physics] ,Physical and Theoretical Chemistry ,Condensed Matter Physics ,Instrumentation ,Spectroscopy - Abstract
International audience
- Published
- 2022
9. Testing pyroxenite versus peridotite sources for marine basalts using U-series isotopes
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Sarah Lambart, L. J. Elkins, Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Thermal equilibrium ,Peridotite ,Basalt ,010504 meteorology & atmospheric sciences ,Isotope ,Lithology ,Geochemistry ,Geology ,010502 geochemistry & geophysics ,01 natural sciences ,Mantle (geology) ,System a ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,Geochemistry and Petrology ,Homogeneous ,0105 earth and related environmental sciences - Abstract
Geochemically enriched signatures in global oceanic basalts have long indicated a heterogeneous mantle source, but the role of lithologic heterogeneity in producing mantle partial melts, particularly fertile pyroxenite rocks, remains unclear. Uranium-series disequilibria in basalts are particularly sensitive to the increased garnet mode and melting rates of pyroxenite rocks, making the system a useful indicator of mantle lithologic heterogeneity in the melt region for oceanic basalts. Here we summarize evidence for the presence and importance of pyroxenite rocks in the upper mantle and their role in melt generation of mid-ocean ridge basalts and ocean island basalts, with a synthesis of U-series disequilibrium systematics in oceanic basalts and implications for global lithologic heterogeneity of the upper mantle. We further synthesize the melt modeling approaches for the interpretation of U-series disequilibria in basalts and demonstrate the use of numerical solution models for time-dependent reactive porous flow and dynamic melting during decompression of a two-lithology mantle in thermal equilibrium. Our model outcomes corroborate prior interpretations in favor of reactive porous flow and two-porosity transport for relatively homogeneous, peridotite-dominated mantle regimes, and further support contributions of pyroxenite partial melts to aggregated melts in order to reproduce the heterogeneous global basalt data. To most accurately predict the conditions of melting by comparison with measured data, two-lithology melting calculations should carefully consider the role of thermal equilibrium, mineral/melt partitioning, non-linear variations in mineral modes, and degree of melting during the melting process.
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- 2019
10. Condensation temperatures of trace elements during Moon formation
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Caroline Fitoussi, Bernard Bourdon, and Dmitry Ivanov
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Trace (semiology) ,Chemistry ,Condensation ,Astrobiology - Published
- 2021
11. Mass-independent fractionation of Cr isotopes during photo-oxidation of Cr(III) in solution
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Caroline Fitoussi, Bernard Bourdon, and Mélie Cornet
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Chromium ,chemistry ,Radiochemistry ,chemistry.chemical_element ,Cr isotopes ,Mass-independent fractionation - Published
- 2021
12. Silicon isotopes in SNC meteorites : a record of accretion or differentiation of Mars ?
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Delphine Losno, Bernard Bourdon, and Caroline Fitoussi
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Meteorite ,Mars Exploration Program ,Isotopes of silicon ,Accretion (astrophysics) ,Geology ,Astrobiology - Published
- 2021
13. Molybdenum isotope fractionation in uranium oxides and during key processes of the nuclear fuel cycle: Towards a new nuclear forensic tool
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Eric Pili, Bernard Bourdon, Caroline Fitoussi, Valérie Migeon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Nuclear fuel cycle ,010504 meteorology & atmospheric sciences ,Isotope ,Nuclear forensics ,Geochemistry ,chemistry.chemical_element ,Uranium ,010502 geochemistry & geophysics ,01 natural sciences ,chemistry.chemical_compound ,Uranium ore ,Isotope fractionation ,chemistry ,Geochemistry and Petrology ,Ammonium diuranate ,[SDE]Environmental Sciences ,Environmental science ,Mineral processing ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
The ability to identify the sources of nuclear materials using various analytical methods has become a major target of nuclear forensics science. However, despite the emergence of novel tools developed in recent years, it has become obvious that accurate identification of sources requires multiple tools. Here, we have developed a new isotope tool based on Mo isotopes that could be used in nuclear forensics. Molybdenum is a trace element that is found in significant levels in uranium ores (0.5–4800 ppm), uranium minerals (0.02–6000 ppm) and uranium ore concentrates (UOCs, from 0.7 to 1400 ppm). The Mo isotope composition, reported as δ98Mo was analyzed in these materials and shown to have a significant variability from −2.62 to +0.30‰ in uranium ores and from −3.50 to +0.46‰ in UOCs. In uranium ores, the largest Mo isotope fractionation is found in deposits of sedimentary origin while the few ores with a magmatic origin show limited Mo isotope fractionation. Thus, the Mo isotope ratios may ultimately be used to distinguish high temperature from low temperature uranium ores. The δ98Mo values in UOCs also show a significant range that not only originate from variations in ore compositions but can also be attributed to ore processing such as leaching, solvent extraction, resin extraction and UOC precipitation. Laboratory experiments based on existing protocols of uranium ore separation demonstrate the existence of sizeable Mo isotope fractionation associated with these processes. Experiments with solvent extraction and precipitation of ammonium diuranate and peruranate show that the refined uranium fraction is enriched in light Mo isotopes in both cases. In the case of a uranium ore (SOMAIR, Niger) and associated UOC, the observed fractionation can possibly be assigned to the combined effect of solvent extraction and precipitation, although Mo isotope variability in ores and UOCs may make such a diagnostic difficult. Ultimately, these experiments can be used to reconstruct the Mo isotope composition of the ore, if there is sufficient knowledge about the ore processing flowsheet or to provide information about the type of uranium ore. Alternatively, it could be used to identify the process used for manufacturing a given UOC, if one can make an estimate about the composition of the ore, probably in conjunction with other tools. Our study demonstrates the potential of Mo isotopes as a useful tool in the field of nuclear forensics.
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- 2020
14. Redox and structural controls on tin isotopic fractionations among magmas
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M. Roskosz, Michael Hu, Laurent Tissandier, Esen E. Alp, Ayman Said, Nicolas Dauphas, Quentin Amet, Caroline Fitoussi, Ahmet Alatas, Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Unité Matériaux et Transformations - UMR 8207 (UMET), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut National de la Recherche Agronomique (INRA), Origins Laboratory [Chicago], Department of Geophysical Sciences [Chicago], University of Chicago-University of Chicago-Enrico Fermi Institute, University of Chicago, Institute of Geochemistry and Petrology, Advanced Photon Source [ANL] (APS), Argonne National Laboratory [Lemont] (ANL)-University of Chicago-US Department of Energy, Advanced Photon Source, Argonne National Laboratory [Lemont] (ANL), Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centrale Lille Institut (CLIL), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), and Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)
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Fractional crystallization (geology) ,010504 meteorology & atmospheric sciences ,Isotope ,Coordination number ,Analytical chemistry ,chemistry.chemical_element ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,engineering.material ,010502 geochemistry & geophysics ,Anorthite ,01 natural sciences ,Isotope fractionation ,chemistry ,13. Climate action ,Geochemistry and Petrology ,[SDU]Sciences of the Universe [physics] ,Isotopes of tin ,Enstatite ,engineering ,Tin ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
Recent analytical developments have made possible the determination of the isotopic composition of tin in igneous rocks. In order to establish a framework to interpret the mass-dependent tin isotopic signatures of planetary materials, seven geologically-relevant silicate glasses (basalt, rhyolite, enstatite and anorthite glasses) were synthesized with moderate amounts of 119Sn (on the order of a weight percent). Redox conditions were controlled during sample synthesis to set the redox ratio (Sn2+/Sntot) from stannous (Sn2+) to stannic (Sn4+) glasses. The mean force constants of tin bonds in these glasses were determined by synchrotron nuclear resonant inelastic X-ray scattering (NRIXS) in order to determine the reduced isotopic partition function ratios (β-factors) of these glasses. Clues on the coordination chemistry and the valence state of tin in these glasses were also derived from synchrotron Mossbauer spectroscopy (SMS). The force constants of tin drastically increases from Sn2+-bearing to Sn4+-bearing glasses and varies significantly with the glass composition at a given redox state. The average coordination number of tin likely controls these variations with glass composition as suggested by SMS results. It is concluded that large isotope fractionation is expected between materials containing Sn2+ and Sn4+ respectively even at magmatic temperatures and that the coordination chemistry of tin in silicates strongly affect its isotope partitioning behavior. Our experimental data are finally used to interpret available Sn isotope data collected in terrestrial rocks. The incompatible behavior of Sn4+ in mantle minerals leads to a enrichment in heavy isotopes in mantle melts and to the depletion in heavy isotopes in solid residues of melting with a magnitude consistent with the isotope fractionation between Sn2+ and Sn4+ predicted by NRIXS data. Finally, we show that during fractional crystallization of basalt and considering the effect of tin coordination number in minerals and melts, the partitioning of Sn4+ into ilmenite leads to an enrichment in light isotopes in the residual melt.
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- 2020
15. Isotope Fractionation during Condensation and Evaporation during Planet Formation Processes
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Caroline Fitoussi, Bernard Bourdon, Bourdon, Bernard, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,Analytical chemistry ,Evaporation ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,[SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Fractionation ,010502 geochemistry & geophysics ,Protoplanetary disk ,01 natural sciences ,evaporation ,Isotope fractionation ,Geochemistry and Petrology ,Planet ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Vaporization ,[SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Physics::Atomic Physics ,fractionation ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Isotope ,Chemistry ,Condensation ,condensation ,13. Climate action ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics - Abstract
International audience; During the early stages of a protoplanetary disk, it is expected that the temperatures reached in the disk will lead to total or partial vaporization of dust, followed by condensation upon cooling. Similarly, chondrule forming events or giant impacts followed by magma oceans can also produce partial evaporation. Thus, moderately volatile elements can be mobilized during these thermal events, thereby leading to characteristic isotope signatures that can be used to decipher the conditions of elemental fractionation. Indeed, the magnitude of isotope fractionation of moderately volatile elements is directly modulated by the partial pressure of the element of interest. Thus, the isotope fractionation pattern for a given level of elemental depletion can be used to infer the 2 pressure conditions during condensation or evaporation, thus providing strong constraints on astrophysical settings. The observations made on moderately volatile elements or on some major elements such as Mg, Si, or Fe isotopes demonstrate that the isotope signature is most generally more subdued than that of vacuum evaporation producing the maximum isotope fractionation. Thus, experimental studies showing the existence of kinetic isotope fractionation associated with evaporation experiments are not sufficient to interpret cosmochemical data. In this study, we show that the evaporation or condensation coefficients may play a key role in controlling isotope fractionation. The possible role of composition and temperature on the values of evaporation/condensation coefficients are emphasized. Similarly, the role of diffusion in the gas phase leading to a back reaction of condensation during evaporation (or vice-versa) is addressed. In addition, we demonstrate that a new expression linking elemental depletion and isotope fractionation needs to be used in the case of evaporation or condensation in a closed system. Specifically, for condensation in a closed system, one needs to take into account the effect of decreasing oversaturation to model isotope fractionation. We also explored the effect of having a population of grains rather than a single grain on isotope fractionation associated with evaporation on the isotope trajectories. Last, the case of evaporation with multiple species produces a situation where the isotope fractionation pattern is modified. Overall, this study demonstrates a wealth of behaviors in isotope tracers associated with volatile loss that needs to be carefully investigated to fully exploit the information carried by them.
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- 2020
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16. Molybdenum isotope fractionation during acid leaching of a granitic uranium ore
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Caroline Fitoussi, Valérie Migeon, Bernard Bourdon, Eric Pili, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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inorganic chemicals ,Nuclear fuel cycle ,Granite ,Molybdenum isotopes ,chemistry.chemical_element ,Fractionation ,010501 environmental sciences ,010502 geochemistry & geophysics ,01 natural sciences ,chemistry.chemical_compound ,Adsorption ,Isotope fractionation ,Geochemistry and Petrology ,Nitric acid ,0105 earth and related environmental sciences ,Nuclear forensics ,Radiochemistry ,technology, industry, and agriculture ,Sulfuric acid ,Uranium ,Acid leaching ,chemistry ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,Leaching (metallurgy) - Abstract
As an attempt to prevent illicit trafficking of nuclear materials, it is critical to identify the origin and transformation of uranium materials from the nuclear fuel cycle based on chemical and isotope tracers. The potential of molybdenum (Mo) isotopes as tracers is considered in this study. We focused on leaching, the first industrial process used to release uranium from ores, which is also known to extract Mo depending on chemical conditions. Batch experiments were performed in the laboratory with pH ranging from 0.3 to 5.5 in sulfuric acid. In order to span a large range in uranium and molybdenum yields, oxidizers such as nitric acid, hydrogen peroxide and manganese dioxide were also added. An enrichment in heavy Mo isotopes is produced in the solution during leaching of a granitic uranium ore, when Mo recovery is not quantitative. At least two Mo reservoirs were identified in the ore: similar to 40% as Mo oxides soluble in water or sulfuric acid, and similar to 40% of Mo hosted in sulfides soluble in nitric acid or hydrogen peroxide. At pH \textgreater 1.8, adsorption and/or precipitation processes induce a decrease in Mo yields with time correlated with large Mo isotope fractionations. Quantitative models were used to evaluate the relative importance of the processes involved in Mo isotope fractionation: dissolution, adsorption, desorption, precipitation, polymerization and depolymerization. Model best fits are obtained when combining the effects of dissolution/precipitation, and adsorption/desorption onto secondary minerals. These processes are inferred to produce an equilibrium isotope fractionation, with an enrichment in heavy Mo isotopes in the liquid phase and in light isotopes in the solid phase. Quantification of Mo isotope fractionation resulting from uranium leaching is thus a promising tool to trace the origin and transformation of nuclear materials. Our observations of Mo leaching are also consistent with observations of natural Mo isotope fractionation taking place during chemical weathering in terrestrial environments where the role of secondary processes such as adsorption is significant. (C) 2018 Elsevier Ltd. All rights reserved.
- Published
- 2018
17. Tin isotope fractionation during magmatic processes and the isotope composition of the bulk silicate Earth
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Xueying Wang, Caroline Fitoussi, Bernard Bourdon, Quentin Amet, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Bulk silicate earth ,Basalt ,Peridotite ,Redox state ,010504 meteorology & atmospheric sciences ,Isotope ,Stable isotope ratio ,Partial melting ,Geochemistry ,010502 geochemistry & geophysics ,01 natural sciences ,Silicate ,chemistry.chemical_compound ,Isotope fractionation ,chemistry ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,Geochemistry and Petrology ,Oceanic crust ,Sn isotopes ,0105 earth and related environmental sciences - Abstract
Tin is a moderately volatile element whose isotope composition can be used to investigate Earth and planet differentiation and the early history of the Solar System. Although the Sn stable isotope composition of several geological and archaeological samples has been reported, there is currently scarce information about the effect of igneous processes on Sn isotopes. In this study, high-precision Sn isotope measurements of peridotites and basalts were obtained by MC-ICP-MS with a double-spike technique. The basalt samples display small variations in delta Sn-124/116 ranging from -0.01 +/- 0.11 to 0.27 +/- 0.11 parts per thousand (2 s.d.) relative to NIST SRM 3161a standard solution, while peridotites have more dispersed and more negative delta Sn-124 values ranging from -1.04 +/- 0.11 to -0.07 +/- 0.11 parts per thousand (2 s.d.). Overall, basalts are enriched in heavy Sn isotopes relative to peridotites. In addition, delta Sn-124 in peridotites become more negative with increasing degrees of melt depletion. These results can be explained by different partitioning behavior of Sn4+ and Sn2+ during partial melting. Sn4+ is overall more incompatible than Sn2+ during partial melting, resulting in Sn4+-rich silicate melt and Sn2+-rich residue. As Sn4+ has been shown experimentally to be enriched in heavy isotopes relative to Sn2+, the effect of melting is to enrich residual peridotites in relatively more compatible Sn2+, which results in isotopically lighter peridotites and isotopically heavier mantle-derived melts. This picture can be disturbed partly by the effect of refertilization. Similarly, the presence of enriched components such as recycled oceanic crust or sediments could explain part of the variations in Sn isotopes in oceanic basalts. The most primitive peridotite analyzed in this study was used for estimating the Sn isotope composition of the BSE, with delta Sn-124 = -0.08 +/- 0.11 parts per thousand (2 s.d.) relative to the Sn NIST SRM 3161a standard solution. Altogether, this suggests that Sn isotopes may be a powerful probe of redox processes in the mantle. (C) 2018 Elsevier Ltd. All rights reserved.
- Published
- 2018
18. Physical processes occurring in tight gas reservoirs from Western Canadian Sedimentary Basin: Noble gas signature
- Author
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Matthias S. Brennwald, Magali Pujol, Rolf Kipfer, Bernard Bourdon, Sander H. J. M. van den Boorn, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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010504 meteorology & atmospheric sciences ,Geochemistry ,010502 geochemistry & geophysics ,01 natural sciences ,Tight gas play ,Geochemistry and Petrology ,Natural gas ,Tight gas ,0105 earth and related environmental sciences ,geography ,geography.geographical_feature_category ,business.industry ,Noble gas ,Geology ,Sedimentary basin ,Unconventional oil ,Petroleum reservoir ,Basin centered gas play ,Noble gases ,Petroleum system ,Natural gas field ,Source rock ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,business - Abstract
Noble gases have become a powerful tool to constrain the origin of fluids as well as the rates of fluid migration in sedimentary basins. The aim of this study was to apply these tracers to understand the genesis and the evolution of unconventional gas reservoirs, basin-centered gas reservoirs (also called tight-gas reservoirs). A natural laboratory for this study is the methane-rich gas field in Cretaceous tight sands from the Western Canadian Sedimentary Basin (WCSB). The selection of the WCSB was motivated by an easy access to wells that cover an extensive area from deep to shallow parts of the basin, as well as the relatively well documented geology and hydrology of the area. The elemental noble gas signature (He, Ar, Kr and Xe) of natural gas from 18 wells of the basin shows a mixture between the original low content noble gas signature of the hydrocarbon gas (after its charge into the reservoir) and water (trapped in intergranular volumes (IGV)), which is comparatively rich in noble gases. This difference in relative contents can be used to estimate the geographical position of the contact between the gas reservoir and the shallower IGV water. Furthermore, the ‘original’ noble gas signature, which is defined as the noble gases generated in the source, later transferred, and mixed with in situ produced noble gases in the reservoir, is mainly composed of radiogenic isotopes (40Ar and 4He). The comparison of 4He/40Ar ratios with an average value for potential source rocks and reservoir rocks production ratio (estimated with U, Th and K concentrations) allows us to understand how the gas was transferred from the source rock to the reservoir rock. These results, combined with the geological and hydrological knowledge of the WCSB, affords a new method to better understand the dynamics of unconventional gas reservoirs.
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- 2018
19. Evaporation and isotope fractionation in a TIMS source
- Author
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Bernard Bourdon, Caroline Fitoussi, Mélie Cornet, Mathieu Touboul, Institute of Geochemistry and Petrology, Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Touboul, Mathieu
- Subjects
[SDU] Sciences of the Universe [physics] ,[SDU]Sciences of the Universe [physics] ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,[SDU.STU.GC] Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,[SDU.STU] Sciences of the Universe [physics]/Earth Sciences ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences - Abstract
International audience; Understanding the stable isotope record of meteorites requires a quantitative knowledge of isotope fractionation related to thermal events leading to vaporization of elements as refractory as Mg (T50%condensation=1336 K). However, so far few experiments, except for major elements are available to determine the isotope fractionation linked with the kinetic process of evaporation. In this study, we have used the evaporation of various elements (e.g. Nd, Cr) analyzed by thermal ionization mass spectrometry to characterize the isotope fractionation and the thermodynamics of evaporation from a TIMS filament under various conditions. In the first part of this study, we investigated the thermodynamic conditions of Cr evaporation by simulating the chemical equilibrium of the mixture of the element of interest with the activator to predict the vapor pressure and speciation in equilibrium at the temperature of ion emission. This enables to predict free evaporation rate of species to be compared with the observed ion beam and to optimize the running conditions. Based on the ion beam signal, one should be able to obtain a crude estimate of the evaporation coefficients. In a second part of this study, the observed isotope fractionation was first characterized using the classical exponential law. It was found as has been reported previously that after mass fractionation correction, there is a small residual trend in the Cr isotope ratios corrected for mass fractionation plotted one against each other. A new mass fractionation law based on first principles was derived and found to remove any temporal trend mass fractionation. This mass fractionation law yields more reproducible results and allows to estimate the kinetic mass fractionation coefficients associated with evaporation.
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- 2019
20. Elemental and isotopic variability in solar system materials by mixing and processing of primordial disk reservoirs
- Author
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Bernard Bourdon, Ulrik Hans, Christoph Burkhardt, Nicolas Dauphas, Thorsten Kleine, Institute of Geochemistry and Petrology, Origins Laboratory [Chicago], Department of Geophysical Sciences [Chicago], University of Chicago-University of Chicago-Enrico Fermi Institute, University of Chicago, and Biozentrum der LMU München
- Subjects
Murchison meteorite ,CAIs ,Materials science ,010504 meteorology & atmospheric sciences ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Mineralogy ,FOS: Physical sciences ,010502 geochemistry & geophysics ,01 natural sciences ,Sr isotopes ,Allende meteorite ,Geochemistry and Petrology ,Chondrite ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Ti isotopes ,Early solar system ,Chemical composition ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences ,Earth and Planetary Astrophysics (astro-ph.EP) ,Presolar grains ,Chondrule ,Meteorite ,13. Climate action ,Physics::Space Physics ,Astrophysics::Earth and Planetary Astrophysics ,Formation and evolution of the Solar System ,Nucleosynthesis ,Meteorites ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Isotope anomalies among planetary bodies provide key constraints on planetary genetics and the Solar System's dynamical evolution. However, to unlock the full potential of these anomalies for constraining the processing, mixing, and transport of material in the disk it is essential to identify the main components responsible for producing planetary-scale isotope variations, and to investigate how they relate to the isotopic heterogeneity inherited from the Solar System's parental molecular cloud. To address these issues we measured the Ti and Sr isotopic compositions of Ca,Al-rich inclusions (CAIs) from the Allende CV3 chondrite, as well as acid leachates and an insoluble residue from the Murchison CM2 chondrite, and combine these results with literature data for presolar grains, hibonites, chondrules, and bulk meteorites. Our analysis reveals that the mineral-scale nebular isotopic heterogeneity as sampled by leachates and presolar grains is largely decoupled from the planetary-scale isotope anomalies. Combining isotope anomaly data for a large number of elements reveals that the difference between non-carbonaceous (NC) and carbonaceous (CC) meteorites is the product of mixing between NC material and a nebular reservoir (termed IC) whose isotopic composition is similar to that of CAIs, but whose chemical composition is similar to bulk chondrites. In our preferred model, the distinct isotopic compositions of these two nebular reservoirs reflect an inherited heterogeneity of the solar system's parental molecular cloud core, which therefore has never been fully homogenized during collapse. Planetary-scale isotopic anomalies are thus caused by variable mixing of isotopically distinct primordial disk reservoirs, the selective processing of these reservoirs in different nebular environments, and the heterogeneous distribution of the thereby forming nebular products., Accepted for publication in Geochimica et Cosmochimica Acta
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- 2019
21. More than Five Percent Ionization Efficiency by Cavity Source Thermal Ionization Mass Spectrometry for Uranium Subnanogram Amounts
- Author
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Anne Trinquier, Bernard Bourdon, Anne-Laure Fauré, Colin Maden, Fabien Pointurier, Amélie Hubert, Maria Schönbächler, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)
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Isotope ,Chemistry ,Nuclear forensics ,010401 analytical chemistry ,Radiochemistry ,chemistry.chemical_element ,Thermal ionization mass spectrometry ,Uranium ,010402 general chemistry ,01 natural sciences ,7. Clean energy ,0104 chemical sciences ,Analytical Chemistry ,Nuclear safeguards ,[SDU]Sciences of the Universe [physics] ,Ionization - Abstract
Numerous applications require the precise analysis of U isotope relative enrichment in sample amounts in the sub-nanogram to picogram range, among those are nuclear forensics, nuclear safeguards, environmental survey and geosciences. However, conven-tional thermal ionization mass spectrometry (TIMS) yields U combined ionization and transmission efficiencies (i.e ratio of ions detected to sample atoms loaded) less than 0.1 or 2% depending on the loading protocol, motivating the development of sources capable of enhancing ionization. The new prototype cavity source TIMS at ETH offers improvements from 4 to 15 times in com-bined ionization and transmission efficiency compared to conventional TIMS, yielding up to 5.6 % combined efficiency. Uranium isotope ratios have been determined on reference standards in the 100 pg range bound to ion-exchange or extraction resin beads. For natural U standards, n(235U)/n(238U) ratios are measured to relative external precisions of 0.5 to 1.0 % (2RSD, 2
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- 2019
22. Numerical simulations of magnetic electron-impact ion source
- Author
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Dmitry Ivanov, Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Chemistry ,010401 analytical chemistry ,Electron ,010402 general chemistry ,Condensed Matter Physics ,Mass spectrometry ,01 natural sciences ,7. Clean energy ,Ion source ,0104 chemical sciences ,Ion ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,[CHIM.ANAL]Chemical Sciences/Analytical chemistry ,Ionization ,Electric field ,Atom ,Physics::Atomic and Molecular Clusters ,Physical and Theoretical Chemistry ,Atomic physics ,Instrumentation ,Spectroscopy ,Electron ionization ,ComputingMilieux_MISCELLANEOUS - Abstract
An electron impact ion source equipped with a magnet has been designed for enhancing the ionization efficiency of such ion sources with potential applications in Knudsen effusion mass spectrometry or electron impact sources used in gas mass spectrometry. This modernized device utilizes the trapping of electrons in parallel electrical and magnetic fields with the goal of maximizing the probability of impact between an electron and an atom or molecule to be ionized. The influence of magnetic and electrical fields on ions and electron trajectories inside the ion source was studied with numerical simulations. Based on the electron and ion trajectories we have modified the classical Nier-type ion source and found the optimal geometrical and potential parameters to provide better electron ionization and higher ion extraction efficiency. This design has the potential to enhance ionization efficiency by a factor of ∼15–20 compared with existing designs.
- Published
- 2019
23. Size and density sorting of dust grains in SPH simulations of protoplanetary disc II: Fragmentation
- Author
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Caroline Fitoussi, Bernard Bourdon, Jean-François Gonzalez, Francesco C. Pignatale, Institute of Geochemistry and Petrology, Muséum national d'Histoire naturelle (MNHN), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), ANR-10-LABX-0066,LIO,Lyon Institute of Origins(2010), ANR-11-IDEX-0007,Avenir L.S.E.,PROJET AVENIR LYON SAINT-ETIENNE(2011), ANR-15-CE31-0004,CRADLE,Origine des chondrites: une approche croisée entre simulations numériques et analyses en laboratoire(2015), and ANR-16-CE31-0013,PLANET-FORMING-DISKS,De meilleurs modèles pour de meilleures données(2016)
- Subjects
Astrochemistry ,010504 meteorology & atmospheric sciences ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,FOS: Physical sciences ,01 natural sciences ,meteorites ,methods: numerical ,Fragmentation (mass spectrometry) ,Chondrite ,0103 physical sciences ,meteors ,meteoroids ,010303 astronomy & astrophysics ,ComputingMilieux_MISCELLANEOUS ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Meteoroid ,astrochemistry ,Chemical fractionation ,Astronomy and Astrophysics ,protoplanetary discs ,Grain growth ,Meteorite ,Space and Planetary Science ,Chemical physics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Grain growth and fragmentation are important processes in building up large dust aggregates in protoplanetary discs. Using a 3D two-phase (gas-dust) SPH code, we investigate the combined effects of growth and fragmentation of a multi-phase dust with different fragmentation thresholds in a time-evolving disc. We find that our fiducial disc, initially in a fragmentation regime, moves toward a pure-growth regime in a few thousands years. Timescales change as a function of the disc and dust properties. When fragmentation is efficient, it produces, in different zones of the disc, Fe/Si and rock/ice ratios different from those predicted when only pure growth is considered. Chemical fractionation and the depletion/enrichment in iron observed in some chondrites can be linked to the size-density sorting and fragmentation properties of precursor dusty grains . We suggest that aggregation of chondritic components could have occurred where/when fragmentation was not efficient if their aerodynamical sorting has to be preserved. Chondritic components would allow aerodynamical sorting in a fragmentation regime only if they have similar fragmentation properties. We find that, in the inner disc, and for the same interval of time, fragmenting dust can grow larger when compared to the size of grains predicted by pure growth. This counter-intuitive behaviour is due to the large amount of dust which piles up in a fragmenting zone followed by the rapid growth that occurs when this zone transitions to a pure growth regime. As an important consequence, dust can overcome the radial-drift barrier within a few thousands years., Comment: Accepted, MNRAS. ArXiv version, some figures compressed to fit the max allowed size
- Published
- 2019
- Full Text
- View/download PDF
24. List of Contributors
- Author
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Yuri Amelin, Nicholas T. Arndt, Gennadiy Artemenko, Wenqian Bai, Darcy Baker, Stephen J. Barnes, Ann M. Bauer, Robert L. Bauer, Raphael Baumgartner, Richard W. Belcher, Vickie C. Bennett, Ankit Bhandari, Marion E. Bickford, Janne Blichert-Toft, Svetlana Bogdanova, Christian O. Böhm, Bernard Bourdon, Gary R. Byerly, Richard W. Carlson, Nicole Cates, Barbara Cavalazzi, Aaron J. Cavosie, Thomas Chacko, Godfrey Chagondah, Kevin R. Chamberlain, David C. Champion, Stefan Claesson, Kent C. Condie, Brendan Cummins, Alexandra Krull Davatzes, Sukanta Dey, Tara Djokic, Chunyan Dong, Annika Dziggel, J. Elis Hoffmann, Don Francis, Clark R.L. Friend, Yashvardhan Gaur, Steven Goderis, William L. Griffin, Martin Guitreau, Xie Hangqiang, Simon L. Harley, Russell P. Hartlaub, Larry M. Heaman, Esa Heilimo, Christoph Heubeck, Keyron Hickman-Lewis, Axel Hofmann, Pentti Hölttä, Hannu Huhma, David L. Huston, George D. Kamenov, James F. Kasting, Nigel M. Kelly, Anthony I.S. Kemp, Alexander F.M. Kisters, Asko Kontinen, Alfred Kröner, Monika A. Kusiak, Laura Lauri, Morgane Ledevin, Baptiste Lemirre, Evelyn Y. Levine, Yuan Li, Dunyi Liu, Yongsheng Liu, Shoujie Liu, Donald R. Lowe, Yongjun Lu, Mingzhu Ma, Terrence P. Mernagh, Aniruddha Mitra, Stephen J. Mojzsis, Sudipto Mondal, Peter Morant, Jean-Francois Moyen, Paul A. Mueller, Elodie Muller, Thorsten J. Nagel, Jinia Nandy, Pritam Nasipuri, Marc D. Norman, Allen P. Nutman, Jonathan O'Neil, Craig O'Neill, Suzanne Y. O'Reilly, Dominic Papineau, Jayanta K. Pati, Pascal Philippot, Franco Pirajno, Greg Poole, Jesse R. Reimink, Claire Rollion-Bard, Antoine S.G. Roth, Lopamudra Saha, Scott D. Samson, Saheli Sarkar, Aaron M. Satkoski, Manavan Satyanaryanan, Mark D. Schmitz, Graham A. Shields, Leonid Shumlyanskyy, Bruce M. Simonson, Alexandr Slabunov, Robert H. Smithies, Catherine Spaggiari, Luke Steller, Gary Stevens, Kenichiro Sugitani, Sahand Tadbiri, Abhishek Topno, John W. Valley, Martin J. Van Kranendonk, Mark A. van Zuilen, Yusheng Wan, Frances Westall, Simon A. Wilde, Michael T.D. Wingate, Joseph L. Wooden, Stephen Wyche, Hangqiang Xie, Shiwen Xie, Chao Zhang, Siqi Zhang, and Keqing Zong
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- 2019
25. The Assean Lake Complex
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Nicole L. Cates, R. P. Hartlaub, Christian O. Böhm, Larry M. Heaman, Antoine S.G. Roth, Bernard Bourdon, Stephen J. Mojzsis, Martin Guitreau, Janne Blichert-Toft, Department of Geological Sciences [Boulder], University of Colorado [Boulder], Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire de Sciences de la Terre (LST), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement et la société-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Université Jean Monnet [Saint-Étienne] (UJM), Institute of Geochemistry and Petrology, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut de Recherche pour le Développement et la société-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut national des sciences de l'Univers (INSU - CNRS), and École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL)
- Subjects
010504 meteorology & atmospheric sciences ,[SDU]Sciences of the Universe [physics] ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,010502 geochemistry & geophysics ,01 natural sciences ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
International audience
- Published
- 2019
26. Extremely young melt infiltration of the sub-continental lithospheric mantle
- Author
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Bernard Bourdon, Michael Turner, Kari M. Cooper, Simon Turner, Don Porcelli, Macquarie University, and Institute of Geochemistry and Petrology
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Basalt ,Incompatible element ,010504 meteorology & atmospheric sciences ,Physics and Astronomy (miscellaneous) ,Pargasite ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Astronomy and Astrophysics ,010502 geochemistry & geophysics ,01 natural sciences ,Mantle (geology) ,Geophysics ,13. Climate action ,Space and Planetary Science ,Asthenosphere ,Xenolith ,Metasomatism ,Low-velocity zone ,Petrology ,ComputingMilieux_MISCELLANEOUS ,Geology ,0105 earth and related environmental sciences - Abstract
It has long been inferred that mantle metasomatism and the incompatible element enrichment of the continents both require movement of melts formed by very low degree melting of the mantle. Yet establishing the presence of these melts and whether this process is on-going and continuous, or spatially and temporally restricted, has proved difficult. Here we report large U-Th-Ra disequilibria in metasomatised, mantle xenoliths erupted in very young lavas from the Newer Volcanics Province in southeastern Australia. The 226Ra-230Th disequilibria appear to require reappraisal of previous estimates for the age of eruption that now seems unlikely to be more than a few kyr at most. We propose that infiltration of carbonatitic melts/fluids, combined with crystallization of pargasite, can account for the first order U-series disequilibria observations. Irrespective of the exact details of the complex processes responsible, the half-lives of the nuclides require that some of the chemical and isotopic disturbance was extremely young (« 8 kyr) and potentially on-going at the time of incorporation into the alkali basalts that transported the xenoliths to the surface. This provides evidence for the presence and possibly continuing migration of small melt fractions (~0.02%) in the upper convecting mantle that may contribute to the seismic low velocity zone. By implication, it appears that the asthenosphere must lie close to its solidus, at least in this region. Pressure-temperature estimates indicate that the small degree melts identified could infiltrate as far as 25 km upwards into the sub-continental lithospheric mantle leading to strong incompatible element enrichment and the recent timing of this event this urges a reappraisal of the meaning of 300–500 Ma Nd model ages in mantle xenoliths from this region. In principle, the resultant metasomatised mantle could provide a component for some ocean island basalts, should the sub-continental lithospheric mantle be returned to the asthenosphere by convective removal at some later time.
- Published
- 2021
27. Isotope tracers of core formation
- Author
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Mathieu Roskosz, Remco C. Hin, Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Materials science ,010504 meteorology & atmospheric sciences ,Isotope ,Stable isotope ratio ,Thermodynamics ,010502 geochemistry & geophysics ,01 natural sciences ,Stable isotope ,Mantle (geology) ,Silicate ,chemistry.chemical_compound ,Isotope fractionation ,chemistry ,13. Climate action ,Chondrite ,[SDU]Sciences of the Universe [physics] ,Core formation ,Thermal ,General Earth and Planetary Sciences ,Astrophysics::Earth and Planetary Astrophysics ,Volatiles ,0105 earth and related environmental sciences - Abstract
The study of siderophile element isotope compositions in planetary mantles offers a new methodology to constrain the temperatures of core formation, provided there is an appropriate calibration of the temperature-dependence and possibly pressure-dependence of isotope fractionation between metal and silicate and of the metal-silicate partitioning for these elements. In this review, we examine recent studies that have shown that Si, Fe, Mo, Cr, Cu, Ni, N and C could potentially be used to constrain the temperature of metal-silicate equilibration using single stage or continuous models of core formation, yielding contrasted results. Such an approach requires assumptions about the building blocks of the Earth and it is generally considered that the composition of some chondrites is representative of bulk Earth. This is obviously more complex for volatile elements such as Cu, N or C, as the isotope composition of the building blocks of the Earth could have been affected by thermal processing. On the basis of a chondritic bulk composition, one can estimate a temperature of core formation assuming a model for this process. If the metal-silicate equilibration is incomplete, as is likely the case for giant impacts, then the composition of the mantle of the impactor and the fraction of metal that equilibrates needs to be assessed carefully. It has been shown recently that the degree of equilibration will be a function of the metal-silicate partition coefficient and will be hence very different for Si, Cr, or Mo, an aspect that has not been considered in previous studies and may help explain differences in interpretation. In this context, the expected temperatures of equilibration are quite variable and are a function of the impactor's conditions of metal-silicate segregation. Another complication arises when considering continuous models of core formation: the most siderophile elements will be sensitive to the last episodes of core formation, while the budget of less siderophile elements will reflect its integrated accretion history (e.g. Cr or Si). A model including Si, Cr and Mo isotope data that takes into account these aspects has been constructed and shown to be consistent with scenarii that were derived from siderophile element data.
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- 2018
28. Design of a prototype thermal ionization cavity source intended for isotope ratio analysis
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Colin Maden, Anne Trinquier, Amélie Hubert, Jörg Rickli, Anne-Laure Fauré, Bernard Bourdon, Fabien Pointurier, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)
- Subjects
Thermal ionization cavity ,Analytical chemistry ,chemistry.chemical_element ,Thermal ionization ,02 engineering and technology ,Thermal ionization mass spectrometry ,Mass spectrometry ,01 natural sciences ,Ion ,chemistry.chemical_compound ,Uranium oxide ,Physical and Theoretical Chemistry ,Instrumentation ,Spectroscopy ,Isotopes of uranium ,Chemistry ,Electron impact heating ,010401 analytical chemistry ,Uranium ,Ion optics ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Ion source ,0104 chemical sciences ,[SDU]Sciences of the Universe [physics] ,Ion source design ,Ionization efficiency ,0210 nano-technology - Abstract
The design of a prototype thermal ionization cavity (TIC) source attached to the mass analyser of a MAT262 thermal ionization mass spectrometer is presented. In addition to a detailed calculation and experimental verification of the ion optics, the new design includes several innovative features that set it apart from previously reported TIC sources. The goal is to employ this new ion source for high-efficiency isotope ratio analysis. For uranium adsorbed to a single resin bead, an overall efficiency gain of about a factor of 10 compared to the same sample type analysed by state-of-the-art conventional thermal ionization mass spectrometry (TIMS) on a Triton instrument is reported (ions detected per atom loaded). First attempts at isotope ratio analysis of micrometre sized uranium oxide particles, as is commonly done for nuclear safeguards, seem to confirm the enhancement in overall efficiency and could help with the analysis of the minor uranium isotopes on such samples. (C) 2018 Elsevier B.V. All rights reserved.
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- 2018
29. A new method for TIMS high precision analysis of Ba and Sr isotopes for cosmochemical studies
- Author
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Elsa Yobregat, Caroline Fitoussi, Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)
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Strontium ,Isotope ,010401 analytical chemistry ,Analytical chemistry ,chemistry.chemical_element ,Faraday cup ,Mineralogy ,Thermal ionization ,Barium ,010502 geochemistry & geophysics ,Mass spectrometry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Matrix (chemical analysis) ,symbols.namesake ,chemistry ,13. Climate action ,[SDU]Sciences of the Universe [physics] ,symbols ,NIST ,Spectroscopy ,0105 earth and related environmental sciences - Abstract
We present a new method for high precision measurement of both strontium and barium isotopes. Our method is primarily designed for extraterrestrial samples but is actually suitable for any sample, particularly for sampLes with Low Sr and Ba concentrations and complex matrices. The main separation of Sr, Ba and matrix elements is done with Eichrom (TM) Sr resin, which provides a quick and easy way to separate all three fractions with Lithe further purification needed. ALL isotope data were acquired on a Thermal Ionization Mass Spectrometer (TIMS) Thermo Triton (TM) plus. Isotopic ratios were calculated using a muLtidynamic acquisition scheme when possible. The decay of the amplifiers associated with Faraday cups was carefully tuned to ensure that there was no effect in the muLtidynamic acquisition mode. This technique improves the uncertainty for Sr-84/Sr-86, Sr-86/Sr-86 and Ba-135/Ba-136 by a factor of two compared with previous data obtained in static collection mode. The uncertainties attainable with our new method were 2 ppm and 19 ppm (2 s.d.) for the Sr-86/Sr-86 and Sr-84/Sr-86 ratios, respectively and 4 ppm (2 s.d.) for the Ba-135/Ba-136 ratio. The low-abundance Ba-132 isotope was measured with a Faraday cup equipped with a 10(12) Omega resistor to improve the precision of the Ba-132/Ba-136 ratio. We assessed the robustness of our method by measuring several terrestrial rock standards. The use of the muLtidynamic calculation shows the small, but resolvable difference of 20-30 ppm previously observed for the Sr-84/Sr-86 ratio between Earth and isotopic standard SRM NIST 987 (formerly NBS 987), which rules out the hypothesis of a Sr-84 contamination or a fractionation of NIST 987 [Moynier et al., Astrophys. J., 2012, 758, 45; Paton et al., Astrophys. J., 2013, 763, [401 and is in agreement with the results of Hans et al., Earth Planet. Sci. Lett., 2013, 374, 204-214.
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- 2017
30. Size and density sorting of dust grains in SPH simulations of protoplanetary discs
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Francesco C. Pignatale, Nicolás Cuello, Jean-François Gonzalez, Caroline Fitoussi, Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Pontificia Universidad Católica de Chile (UC), Millenium Nucleus Protoplanetary Disks in ALMA Early Science, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), ANR-11-IDEX-0007,Avenir L.S.E.,PROJET AVENIR LYON SAINT-ETIENNE(2011), and ANR-10-LABX-0066,LIO,Lyon Institute of Origins(2010)
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Astrochemistry ,010504 meteorology & atmospheric sciences ,[PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,Sorting (sediment) ,FOS: Physical sciences ,Astrophysics ,01 natural sciences ,meteorites ,methods: numerical ,Smoothed-particle hydrodynamics ,Settling ,Chondrite ,Phase (matter) ,0103 physical sciences ,meteors ,meteoroids ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Meteoroid ,astrochemistry ,Astronomy and Astrophysics ,protoplanetary discs ,Meteorite ,Space and Planetary Science ,[SDU]Sciences of the Universe [physics] ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The size and density of dust grains determine their response to gas drag in protoplanetary discs. Aerodynamical (size x density) sorting is one of the proposed mechanisms to explain the grain properties and chemical fractionation of chondrites. However, the efficiency of aerodynamical sorting and the location in the disc in which it could occur are still unknown. Although the effects of grain sizes and growth in discs have been widely studied, a simultaneous analysis including dust composition is missing. In this work we present the dynamical evolution and growth of multicomponent dust in a protoplanetary disc using a 3D, two-fluid (gas+dust) Smoothed Particle Hydrodynamics (SPH) code. We find that the dust vertical settling is characterised by two phases: a density-driven phase which leads to a vertical chemical sorting of dust and a size-driven phase which enhances the amount of lighter material in the midplane. We also see an efficient radial chemical sorting of the dust at large scales. We find that dust particles are aerodynamically sorted in the inner disc. The disc becomes sub-solar in its Fe/Si ratio on the surface since the early stage of evolution but sub-solar Fe/Si can be also found in the outer disc-midplane at late stages. Aggregates in the disc mimic the physical and chemical properties of chondrites, suggesting that aerodynamical sorting played an important role in determining their final structure., Comment: Astroph version. MNRAS: Accepted 2017 March 30. Received 2017 March 30; in original form 2016 May 10
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- 2017
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31. A new method of Sn purification and isotopic determination with a double-spike technique for geological and cosmochemical samples
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Xueying Wang, Bernard Bourdon, Caroline Fitoussi, Quentin Amet, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Reproducibility ,Accuracy and precision ,Isotope ,Chemistry ,010401 analytical chemistry ,Analytical chemistry ,Standard solution ,010502 geochemistry & geophysics ,Mass spectrometry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Isotope fractionation ,[SDU]Sciences of the Universe [physics] ,Isobaric process ,Analytical procedures ,Spectroscopy ,0105 earth and related environmental sciences - Abstract
This study aimed at developing a new methodology for measuring tin isotope compositions in geological and cosmochemical materials. The analytical procedures included sample treatment, chemical purification and measurement protocol of Sn isotopes by mass spectrometry. A new separation protocol relying on three-stage ion-exchange chromatography was optimized. Sn was separated from matrices and isobaric interferents (i.e. In, Cd and Te), as well as elements that could form molecular isobaric interferents (i.e. Ge, As, Se, Mo and Ag) with a high recovery close to 100%. The Sn isotope analysis was performed by using a Neptune Plus MC-ICP-MS equipped with jet cones. A double-spike technique was used for correcting isotope fractionation during the chemical procedure and instrumental mass bias correction and this method was shown to provide better reproducibility. All measurements were carried out at a concentration of 10 ppb and as little as 20 ng of Sn are sufficient for a single measurement. The precision of Sn standard solution NIST SRM 3161a with the double-spike method was 0.05 parts per thousand (2SD) for delta Sn-124. The intermediate precision of the whole procedure was tested by measuring multiple dissolutions of several geostandards (BHVO-1, BHVO-2 and AGV-1) and a value of 0.11 parts per thousand (2SD) was obtained. This new method has the best precision and accuracy for Sn isotope determination attained so far and has been applied to the analysis of geological and cosmochemical samples.
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- 2017
32. Kinetics of Hg(II) Exchange between Organic Ligands, Goethite, and Natural Organic Matter Studied with an Enriched Stable Isotope Approach
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Ruben Kretzschmar, Erik Björn, Bernard Bourdon, Martin Jiskra, Damian Saile, Jan G. Wiederhold, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Goethite ,010504 meteorology & atmospheric sciences ,Inorganic chemistry ,Chemical Fractionation ,Environment ,010501 environmental sciences ,Ligands ,01 natural sciences ,Metal ,Adsorption ,Isotope fractionation ,Desorption ,Environmental Chemistry ,Organic Chemicals ,0105 earth and related environmental sciences ,Minerals ,Stable isotope ratio ,Chemistry ,Sorption ,Mercury ,General Chemistry ,Models, Theoretical ,Kinetics ,Mercury Isotopes ,Resins, Synthetic ,[SDU]Sciences of the Universe [physics] ,Stability constants of complexes ,Isotope Labeling ,visual_art ,visual_art.visual_art_medium ,Iron Compounds - Abstract
The mobility and bioavailability of toxic Hg(II) in the environment strongly depends on its interactions with natural organic matter (NOM) and mineral surfaces. Using an enriched stable isotope approach, we investigated the exchange of Hg(II) between dissolved species (inorganically complexed or cysteine-, EDTA-, or NOM-bound) and solid-bound Hg(II) (carboxyl-/thiol-resin or goethite) over 30 days under constant conditions (pH, Hg and ligand concentrations). The Hg(II)-exchange was initially fast, followed by a slower phase, and depended on the properties of the dissolved ligands and sorbents. The results were described by a kinetic model allowing the simultaneous determination of adsorption and desorption rate coefficients. The time scales required to reach equilibrium with the carboxyl-resin varied greatly from 1.2 days for Hg(OH)2 to 16 days for Hg(II)-cysteine complexes and approximately 250 days for EDTA-bound Hg(II). Other experiments could not be described by an equilibrium model, suggesting that a significant fraction of total-bound Hg was present in a non-exchangeable form (thiol-resin and NOM: 53-58%; goethite: 22-29%). Based on the slow and incomplete exchange of Hg(II) described in this study, we suggest that kinetic effects must be considered to a greater extent in the assessment of the fate of Hg in the environment and the design of experimental studies, for example, for stability constant determination or metal isotope fractionation during sorption.
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- 2014
33. Small-scale studies of roasted ore waste reveal extreme ranges of stable mercury isotope signatures
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Gordon E. Brown, Bernard Bourdon, Adam D. Jew, Jan G. Wiederhold, Ruben Kretzschmar, Robin S. Smith, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Isotope ,Chemistry ,Metacinnabar ,Mineralogy ,chemistry.chemical_element ,Fractionation ,engineering.material ,Mercury (element) ,Cinnabar ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,Geochemistry and Petrology ,TRACER ,Environmental chemistry ,engineering ,Roasting ,Isotope analysis - Abstract
Active and closed Hg mines are significant sources of Hg contamination to the environment, mainly due to large volumes of mine waste material disposed of on-site. The application of Hg isotopes as source tracer from such contaminated sites requires knowledge of the Hg isotope signatures of different materials potentially released to the environment. Previous work has shown that calcine, the waste residue of the on-site ore roasting process, can exhibit distinct Hg isotope signatures compared with the primary ore. Here, we report results from a detailed small-scale study of Hg isotope variations in calcine collected from the closed New Idria Hg mine, San Benito County, CA, USA. The calcine samples exhibited different internal layering features which were investigated using optical microscopy, micro X-ray fluorescence, micro X-ray absorption spectroscopy (mu-XAS), and stable Hg isotope analysis. Significant Fe, S, and Hg concentration gradients were found across the different internal layers. Isotopic analyses revealed an extreme variation with pronounced isotopic gradients across the internal layered features. Overall, delta Hg-202(+/- 0.10 parts per thousand, 2 SD) describing mass-dependent fractionation (MDF) ranged from -5.96 to 14.49 parts per thousand, which is by far the largest range of delta Hg-202 values reported for any environmental sample. In addition, Delta Hg-199 (+/- 0.06 parts per thousand, 2 SD) describing mass-independent fractionation (MIF) ranged from -0.17 to 0.21 parts per thousand. The mu-XAS analyses suggested that cinnabar and metacinnabar are the dominant Hg-bearing phases in the calcine. Our results demonstrate that the incomplete roasting of HgS ores in Hg mines can cause extreme mass-dependent Hg isotope fractionations at the scale of individual calcine pieces with enrichments in both light and heavy Hg isotopes relative to the primary ore signatures. This finding has important implications for the application of Hg isotopes as potential source tracers for Hg released to the environment from closed Hg mines and highlights the need for detailed source signature identification. (C) 2014 Elsevier Ltd. All rights reserved.
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- 2014
34. Combined147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust
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Martin Guitreau, John F. Rudge, Antoine S.G. Roth, Bernard Bourdon, Janne Blichert-Toft, Stephen J. Mojzsis, Institute of Geochemistry and Petrology, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Sciences de la Terre (LST), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
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Acasta Gneiss ,Felsic ,Hadean ,Archean ,Geochemistry ,Crust ,sub-02 ,Mantle (geology) ,Paleontology ,Geophysics ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Geochemistry and Petrology ,Geology ,Zircon ,Gneiss - Abstract
International audience; Primordial silicate differentiation controlled the composition of Earth's oldest crust. Inherited Nd-142 anomalies in Archean rocks are vestiges of the mantle-crust differentiation before ca. 4300 Ma. Here we report new whole-rock Sm-147,Sm-146-Nd-143,Nd-142 data for the Acasta Gneiss Complex (AGC; Northwest Territories, Canada). Our Sm-147-Nd-143 data combined with literature data define an age of 3371 +/- 141 Ma (2 SD) and yield an initial epsilon Nd-143 of -5.6 +/- 2.1. These results are at odds with the Acasta zircon U-Pb record, which comprises emplacement ages of 3920-3960 Ma. Ten of our thirteen samples show Nd-142 deficits of -9.6 +/- 4.8 ppm (2 SD) relative to the modern Earth. The discrepancy between Nd-142 anomalies and a mid-Archean Sm-147-Nd-143 age can be reconciled with Nd isotope reequilibration of the AGC during metamorphic perturbations at ca. 3400 Ma. A model age of ca. 4310 Ma is derived for the early enrichment of the Acasta source. Two compositional end-members can be identified: a felsic component with Nd-142/Nd-144 identical to the modern Earth and a mafic component with Nd-142/Nd-144 as low as -14.1 ppm. The ca. 4310 Ma AGC source is similar to 200 Myr younger than those estimated for Nuvvuagittuq (northern Quebec) and Isua (Itsaq Gneiss Complex, West Greenland). The AGC does not have the same decoupled Nd-Hf isotope systematics as these other two terranes, which have been attributed to the crystallization of an early magma ocean. The Acasta signature rather is ascribed to the formation of Hadean crust that was preserved for several hundred Myr. Its longevity can be linked to Nd-142 evolution in the mantle and does not require slow mantle stirring times nor modification of its convective mode.
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- 2014
35. Evidence for Mo isotope fractionation in the solar nebula and during planetary differentiation
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Remco C. Hin, Christoph Burkhardt, Bernard Bourdon, Thorsten Kleine, Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Biozentrum der LMU München, Ludwig-Maximilians-Universität München (LMU), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Institute of Geochemistry and Petrology, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)
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010504 meteorology & atmospheric sciences ,Analytical chemistry ,Geochemistry ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Chondrule ,010502 geochemistry & geophysics ,01 natural sciences ,Iron meteorite ,Parent body ,Geophysics ,Isotope fractionation ,Meteorite ,13. Climate action ,Space and Planetary Science ,Geochemistry and Petrology ,Chondrite ,Earth and Planetary Sciences (miscellaneous) ,Achondrite ,ComputingMilieux_MISCELLANEOUS ,Geology ,Planetary differentiation ,0105 earth and related environmental sciences - Abstract
Mass-dependent Mo isotope fractionation has been investigated for a wide range of meteorites including chondrites (enstatite, ordinary and carbonaceous chondrites), iron meteorites, and achondrites (eucrites, angrites and martian meteorites), as well as for lunar and terrestrial samples. Magmatic iron meteorites together with enstatite, ordinary and most carbonaceous chondrites define a common δ 98 / 95 Mo value of − 0.16 ± 0.02 ‰ (relative to the NIST SRM 3134 Mo standard), which is interpreted to reflect the Mo isotope composition of bulk planetary bodies in the inner solar system. Heavy Mo isotope compositions for IAB iron meteorites most likely reflect impact-induced evaporative losses of Mo from these meteorites. Carbonaceous chondrites define an inverse correlation between δ 98 / 95 Mo and metal content, and a positive correlation between δ 98 / 95 Mo and matrix abundance. These correlations are mainly defined by CM and CK chondrites, and may reflect the heterogeneous distribution of an isotopically light metal and/or an isotopically heavy matrix component in the formation region of carbonaceous chondrites. Alternatively, the elevated δ 98 / 95 Mo of the CM and CK chondrites could result from the loss of volatile, isotopically light Mo oxides, that formed under oxidized conditions typical for the formation of these chondrites. The Mo isotope compositions of samples derived from the silicate portion of differentiated planetary bodies are heavy compared to the mean composition of chondrites and iron meteorites. This difference is qualitatively consistent with experimental evidence for Mo isotope fractionation between metal and silicate. The common δ 98 / 95 Mo values of − 0.05 ± 0.03 ‰ of lunar samples derived from different geochemical reservoirs indicate the absence of significant Mo isotope fractionation by silicate differentiation or impact metamorphism/volatilization on the Moon. The most straightforward interpretation of the Mo isotope composition of the lunar mantle corresponds to the formation of a lunar core at a metal–silicate equilibration temperature of 1800 ± 200 °C . The investigated martian meteorites, angrites and eucrites exhibit more variable Mo isotope compositions, which for several samples extend to values above the maximum δ 98 / 95 Mo = + 0.14 ‰ that can be associated with core formation. For these samples post-core formation processes such as partial melting, metamorphism and in the case of meteorite finds terrestrial weathering must have resulted in Mo isotope fractionation. Estimates of the metal–silicate equilibration temperatures for Mars ( 2490 ± 770 °C ) and the angrite parent body ( 1790 ± 230 °C ) are thus more uncertain than that derived for the Moon. Although the Mo isotope composition of the bulk silicate Earth has not been determined as part of this study, a value of − 0.16 ‰ δ 98 / 95 Mo 0 can be predicted based on the chondrite and iron meteorite data and by assuming a reasonable temperature range for core formation in the Earth. This estimate is in agreement with four analyzed basalt standards ( − 0.10 ± 0.10 ). Improved application of mass-dependent Mo isotope fractionation to investigate core formation most of all requires an improved understanding of potential Mo isotope fractionation during processes not related to metal–silicate differentiation.
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- 2014
36. Experimental evidence for Mo isotope fractionation between metal and silicate liquids
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Thorsten Kleine, Remco C. Hin, Max W. Schmidt, Christoph Burkhardt, and Bernard Bourdon
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Isotope ,Stable isotope ratio ,Analytical chemistry ,Mineralogy ,Fractionation ,Mass-independent fractionation ,Silicate ,Equilibrium fractionation ,chemistry.chemical_compound ,Geophysics ,Isotope fractionation ,chemistry ,Space and Planetary Science ,Geochemistry and Petrology ,Mineral redox buffer ,Earth and Planetary Sciences (miscellaneous) ,Geology - Abstract
Stable isotope fractionation of siderophile elements may inform on the conditions and chemical consequences of core–mantle differentiation in planetary objects. The extent to which Mo isotopes fractionate during such metal–silicate segregation, however, is so far unexplored. We have therefore investigated equilibrium fractionation of Mo isotopes between liquid metal and liquid silicate to evaluate the potential of Mo isotopes as a new tool to study core formation. We have performed experiments at 1400 and 1600 °C in a centrifuging piston cylinder. Tin was used to lower the melting temperature of the Fe-based metal alloys to 0.19 ± 0.03 ‰ (95% confidence interval) heavier than that of metal. This fractionation is not significantly affected by the presence or absence of carbon. Molybdenum isotope fractionation is furthermore independent of oxygen fugacity in the range IW −1.79 to IW +0.47, which are plausible values for core formation. Experiments at 1600 °C show that, at equilibrium, the 98Mo/95Mo ratio of silicate is 0.12 ± 0.02 ‰ heavier than that of metal and that the presence or absence of Sn does not affect this fractionation. Equilibrium Mo isotope fractionation between liquid metal and liquid silicate as a function of temperature can therefore be described as Δ Mo Metal – Silicate 98 / 95 = − 4.70 ( ± 0.59 ) × 10 5 / T 2 . Our experiments show that Mo isotope fractionation may be resolvable up to metal–silicate equilibration temperatures of about 2500 °C, rendering Mo isotopes a novel tool to investigate the conditions of core formation in objects ranging from planetesimals to Earth sized bodies.
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- 2013
37. Rb–Sr chronology of volatile depletion in differentiated protoplanets: BABI, ADOR and ALL revisited
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Thorsten Kleine, Bernard Bourdon, and Ulrik Hans
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Eucrite ,Solar System ,Planetesimal ,Accretion (astrophysics) ,Astrobiology ,Geophysics ,Space and Planetary Science ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Formation and evolution of the Solar System ,Protoplanet ,Volatiles ,Achondrite ,Geology - Abstract
A strong depletion in moderately volatile elements is a characteristic feature of many planetary bodies in the inner solar system and either reflects the rapid accretion of planetesimals from an incompletely condensed solar nebula, or is the result of energetic collisions during planetary accretion. To better constrain the origin and timescales of this volatile depletion, we have precisely measured Sr isotope compositions in angrites, eucrites and Ca–Al-rich inclusions (CAI). Angrites have an initial (87Sr/86Sr)ADOR=0.698978±0.000004, which is indistinguishable from (87Sr/86Sr)BABI=0.698970±0.000028 obtained for eucrites. In agreement with earlier studies we find that angrites and eucrites have higher initial 87Sr/86Sr ratios than CAI, at face value corresponding to model timescales for volatile loss of several millions of years. However, all the investigated CAI are characterized by elevated 84Sr/86Sr ratios compared to angrites and eucrites, which we interpret to reflect an excess of r-process Sr in the CAI. If this is correct, then the nucleosynthetic Sr isotope anomalies in the CAI require an upward correction of their measured 87Sr/86Sr. After this correction CAI have an initial (87Sr/86Sr)CAI=0.698975±0.000008, which is indistinguishable from ADOR and BABI. This implies volatile loss from the angrite and eucrite parent bodies within less than ~1 Ma after formation of CAI. The volatile-depleted nature of these differentiated protoplanets thus most likely reflects their rapid accretion from volatile-poor dust in an incompletely condensed solar nebula.
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- 2013
38. The stable calcium isotopic composition of rivers draining basaltic catchments in Iceland
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Ruth S. Hindshaw, Bernard Bourdon, Philip A.E. Pogge von Strandmann, Nathalie Vigier, Kevin W. Burton, Institute of Geochemistry and Petrology [ETH Zurich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institute of Biogeochemistry and Pollutant Dynamics [ETH Zurich], Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Department of Earth Sciences [Oxford], University of Oxford [Oxford], Centre de Recherches Pétrographiques et Géochimiques (CRPG), Université de Lorraine (UL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Earth Sciences [Durham], Durham University, Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), University of Oxford, and Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Iceland ,Drainage basin ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,Weathering ,Fractionation ,010501 environmental sciences ,010502 geochemistry & geophysics ,01 natural sciences ,chemical weathering ,Isotope fractionation ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Precipitation ,Glacial period ,Meltwater ,0105 earth and related environmental sciences ,Basalt ,Hydrology ,geography ,calcium ,geography.geographical_feature_category ,calcium isotopes ,Geophysics ,13. Climate action ,Space and Planetary Science ,Geology - Abstract
Calcium isotopic compositions (δ44/42Ca) were measured in Icelandic rivers draining a range of catchment types. The δ44/42Ca values of the rivers ranged from 0.45‰ to 0.67‰, which in all cases was higher than the δ44/42Ca value of basaltic rock standards (0.42±0.03‰). A single explanation was unable to satisfactorily explain the δ44/42Ca values of all rivers, rather it was found that the rivers formed three distinct groups based on the extent of glacial coverage in each catchment. The Ca isotopic composition of rivers draining catchments with less than 10% glacial cover could be explained by the mixing of water sources: basalt-derived solutes, meltwater (taken to represent meteorological precipitation inputs) and hydrothermal water. However, fractionation of δ44/42Ca in these catchments cannot unequivocally be ruled out. In catchments with greater than 22% glacial cover, Ca isotopic compositions could not be explained by a mixture of water sources and instead reflected a fractionation process, most likely the precipitation of Ca-bearing secondary minerals or the adsorption/ion-exchange of Ca onto mineral surfaces. The fractionation factor (α) for this process was calculated to be 0.9999. The third group of rivers, with partially glaciated (10–21%) catchments, grouped with glaciated catchments with respect to their Sr geochemistry and with non-glaciated catchments with respect to their Ca geochemistry. The difference in the controls of Ca isotope fractionation between glaciated and unglaciated catchments was attributed to different weathering regimes.
- Published
- 2013
39. Mercury Isotope Signatures as Tracers for Hg Cycling at the New Idria Hg Mine
- Author
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Gordon E. Brown, Adam D. Jew, Bernard Bourdon, Hagar Siebner, Jan G. Wiederhold, Robin S. Smith, and Ruben Kretzschmar
- Subjects
Pollution ,Isotope ,Chemistry ,media_common.quotation_subject ,chemistry.chemical_element ,Mercury ,General Chemistry ,Fractionation ,Contamination ,Mining ,United States ,Mercury (element) ,Mercury Isotopes ,Environmental chemistry ,Environmental Chemistry ,Cycling ,media_common ,Isotope analysis ,Roasting - Abstract
Mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) of Hg isotopes provides a new tool for tracing Hg in contaminated environments such as mining sites, which represent major point sources of Hg pollution into surrounding ecosystems. Here, we present Hg isotope ratios of unroasted ore waste, calcine (roasted ore), and poplar leaves collected at a closed Hg mine (New Idria, CA, U.S.A.). Unroasted ore waste was isotopically uniform with δ(202)Hg values from -0.09 to 0.16‰ (± 0.10‰, 2 SD), close to the estimated initial composition of the HgS ore (-0.26‰). In contrast, calcine samples exhibited variable δ(202)Hg values ranging from -1.91‰ to +2.10‰. Small MIF signatures in the calcine were consistent with nuclear volume fractionation of Hg isotopes during or after the roasting process. The poplar leaves exhibited negative MDF (-3.18 to -1.22‰) and small positive MIF values (Δ(199)Hg of 0.02 to 0.21‰). Sequential extractions combined with Hg isotope analysis revealed higher δ(202)Hg values for the more soluble Hg pools in calcines compared with residual HgS phases. Our data provide novel insights into possible in situ transformations of Hg phases and suggest that isotopically heavy secondary Hg phases were formed in the calcine, which will influence the isotope composition of Hg leached from the site.
- Published
- 2013
40. A legacy of Hadean silicate differentiation inferred from Hf isotopes in Eoarchean rocks of the Nuvvuagittuq supracrustal belt (Québec, Canada)
- Author
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Janne Blichert-Toft, Antoine S.G. Roth, Bernard Bourdon, Stephen J. Mojzsis, Martin Guitreau, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Sciences de la Terre (LST), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), and Institute of Geochemistry and Petrology
- Subjects
Radiogenic nuclide ,Felsic ,010504 meteorology & atmospheric sciences ,Hadean ,Geochemistry ,Cummingtonite ,010502 geochemistry & geophysics ,01 natural sciences ,Silicate ,Mantle (geology) ,chemistry.chemical_compound ,Geophysics ,chemistry ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Space and Planetary Science ,Geochemistry and Petrology ,Earth and Planetary Sciences (miscellaneous) ,Mafic ,ComputingMilieux_MISCELLANEOUS ,Geology ,0105 earth and related environmental sciences ,Zircon - Abstract
New Lu–Hf isotopic data for mafic and felsic rocks from the Nuvvuagittuq supracrustal belt (NSB) in northern Quebec (Canada) yield an Eoarchean age of 3864±70 Ma consistent with both zircon U–Pb and whole-rock 147Sm–143Nd chronology, but in disagreement with ca. 4400 Ma ages inferred from the 146Sm–142Nd chronometer ( O'Neil et al., 2008 , O'Neil et al., 2012 ). The Lu–Hf result is interpreted as the mean emplacement age of the different autochthonous units of the NSB. An observed alignment of the data along a Lu–Hf “scatterchron” precludes a Hadean age for the NSB because its isotopic characteristics appear to be controlled by long-term radiogenic ingrowth. Emplacement of the NSB in the Hadean (e.g., 4362 − 54 + 35 Ma if the decay constant of 146Sm of Kinoshita et al. (2012 ) is used with the O'Neil et al., 2008 data) should instead have caused age differences of hundreds of millions of years to manifest as strong deviations from the Lu–Hf scatterchron. Combined Lu–Hf and Sm–Nd data on the same NSB amphibolite samples (Ca-poor cummingtonite- and hornblende-bearing) define a mixing hyperbola at ca. 3800 Ma with end-member compositions representative of the compositional groups identified for these lithologies ( O'Neil et al., 2011 ). Anomalously low 142Nd/144Nd values relative to Bulk Silicate Earth are endemic to a group of rocks in the NSB termed “low-TiO2” amphibolites; this is attributable to an ancient multi-stage history of their mantle source. Modeling shows that the 142Nd/144Nd deficits could have developed in response to a re-fertilization episode within a previously fractionated mantle domain at 4510 Ma.
- Published
- 2013
41. Introduction to U-series geochemistry
- Author
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Craig C. Lundstrom, Bernard Bourdon, Gideon M. Henderson, and Simon Turner
- Subjects
Series (stratigraphy) ,Earth science ,Geochemistry ,The Renaissance ,law.invention ,Plate tectonics ,Marine chronometer ,Geochemistry and Petrology ,law ,Planet ,Sufficient time ,Earth (chemistry) ,Igneous petrology ,Geology - Abstract
During the last century, the Earth Sciences underwent two major revolutions in understanding. The first was the recognition of the great antiquity of the Earth and the second was the development of plate tectonic theory. These leaps in knowledge moved geology from its largely descriptive origins and established the modern, quantitative, Earth Sciences. For any science, and particularly for the Earth Sciences, time scales are of central importance. Until recently, however, the study of time scales in the Earth Sciences was largely restricted to the unraveling of the ancient history of our planet. For several decades, Earth scientists have used a variety of isotope chronometers to unravel the long-term evolution of the planet. A fuller understanding of the physical and chemical processes driving this evolution often remained elusive because such processes occur on time scales (1–105 years) which are simply not resolvable by most conventional chronometers. The U-series isotopes, however, do provide tools with sufficient time resolution to study these Earth processes. During the last decade, the Earth Sciences have become increasingly focused on fundamental processes and U-series geochemistry has witnessed a renaissance, with widespread application in disciplines as diverse as modern oceanography and igneous petrology. The uranium and thorium decay-series contain radioactive isotopes of many elements (in particular, U, Th, Pa, Ra and Rn). The varied geochemical properties of these elements cause nuclides within the chain to be fractionated in different geological environments. while the varied half-lives of the nuclides allows investigation of processes occurring on time scales from days to 105 years. U-series measurements have therefore revolutionized the Earth Sciences by offering some of the only quantitative constraints on time scales applicable to the physical processes that take place on the Earth. The application of U-series geochemistry to the Earth Sciences was thoroughly summarized in 1982 …
- Published
- 2016
42. Hf-W chronology of the accretion and early evolution of asteroids and terrestrial planets
- Author
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Alex N. Halliday, Qing-Zhu Yin, Francis Nimmo, Mathieu Touboul, Bernard Bourdon, Herbert Palme, Stein B. Jacobsen, Thorsten Kleine, and Klaus Mezger
- Subjects
Eucrite ,Meteorite ,Geochemistry and Petrology ,Planet ,Chondrite ,Chondrule ,Terrestrial planet ,Parent body ,Geology ,Mantle (geology) ,Astrobiology - Abstract
The 182Hf-182W systematics of meteoritic and planetary samples provide firm constraints on the chronology of the accretion and earliest evolution of asteroids and terrestrial planets and lead to the following succession and duration of events in the earliest solar system. Formation of Ca,Al-rich inclusions (CAIs) at 4568.3 ± 0.7 Ma was followed by the accretion and differentiation of the parent bodies of some magmatic iron meteorites within less than ∼1 Myr. Chondrules from H chondrites formed 1.7 ± 0.7 Myr after CAIs, about contemporaneously with chondrules from L and LL chondrites as shown by their 26Al-26Mg ages. Some magmatism on the parent bodies of angrites, eucrites, and mesosiderites started as soon as ∼3 Myr after CAI formation and may have continued until ∼10 Myr. A similar timescale is obtained for the high-temperature metamorphic evolution of the H chondrite parent body. Thermal modeling combined with these age constraints reveals that the different thermal histories of meteorite parent bodies primarily reflect their initial abundance of 26Al, which is determined by their accretion age. Impact-related processes were important in the subsequent evolution of asteroids but do not appear to have induced large-scale melting. For instance, Hf-W ages for eucrite metals postdate CAI formation by ∼20 Myr and may reflect impact-triggered thermal metamorphism in the crust of the eucrite parent body. Likewise, the Hf-W systematics of some non-magmatic iron meteorites were modified by impact-related processes but the timing of this event(s) remains poorly constrained. The strong fractionation of lithophile Hf from siderophile W during core formation makes the Hf-W system an ideal chronometer for this major differentiation event. However, for larger planets such as the terrestrial planets the calculated Hf-W ages are particularly sensitive to the occurrence of large impacts, the degree to which impactor cores re-equilibrated with the target mantle during large collisions, and changes in the metal-silicate partition coefficients of W due to changing fO2 in differentiating planetary bodies. Calculated core formation ages for Mars range from 0 to 20 Myr after CAI formation and currently cannot distinguish between scenarios where Mars formed by runaway growth and where its formation was more protracted. Tungsten model ages for core formation in Earth range from ∼30 Myr to >100 Myr after CAIs and hence do not provide a unique age for the formation of Earth. However, the identical 182W/184W ratios of the lunar and terrestrial mantles provide powerful evidence that the Moon-forming giant impact and the final stage of Earth's core formation occurred after extinction of 182Hf (i.e., more than ∼50 Myr after CAIs), unless the Hf/W ratios of the bulk silicate Moon and Earth are identical to within less than ∼10%. Furthermore, the identical 182W/184W of the lunar and terrestrial mantles is difficult to explain unless either the Moon consists predominantly of terrestrial material or the W in the proto-lunar magma disk isotopically equilibrated with the Earth's mantle. Hafnium-tungsten chronometry also provides constraints on the duration of magma ocean solidification in terrestrial planets. Variations in the 182W/184W ratios of martian meteorites reflect an early differentiation of the martian mantle during the effective lifetime of 182Hf. In contrast, no 182W variations exist in the lunar mantle, demonstrating magma ocean solidification later than ∼60 Myr, in agreement with 147Sm-143Nd ages for ferroan anorthosites. The Moon-forming giant impact most likely erased any evidence of a prior differentiation of Earth's mantle, consistent with a 146Sm-142Nd age of 50-200 Myr for the earliest differentiation of Earth's mantle. However, the Hf-W chronology of the formation of Earth's core and the Moon-forming impact is difficult to reconcile with the preservation of 146Sm-142Nd evidence for an early (
- Published
- 2016
43. Uranium Decay Series
- Author
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Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), White, William M., Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010504 meteorology & atmospheric sciences ,Decay Chain ,[SDU]Sciences of the Universe [physics] ,Submarine Groundwater Discharge ,Decay Series ,Melting Rate ,010503 geology ,Secular Equilibrium ,010502 geochemistry & geophysics ,01 natural sciences ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
International audience
- Published
- 2016
44. Determination of ionization efficiencies of thermal ionization cavity sources by numerical simulation of charged particle trajectories including space charge
- Author
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Anne-Laure Fauré, Amélie Hubert, Colin Maden, Fabien Pointurier, Bernard Bourdon, Heinrich Baur, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Thermal ionization cavity ,Thermal ionization ,02 engineering and technology ,01 natural sciences ,Space charge ,Ionization ,Physical and Theoretical Chemistry ,Instrumentation ,Spectroscopy ,Electron ionization ,Charged particle optics ,Chemistry ,010401 analytical chemistry ,Cavity geometry ,Plasma ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Charged particle ,Ion source ,0104 chemical sciences ,[SDU]Sciences of the Universe [physics] ,Ionization efficiency ,Atomic physics ,0210 nano-technology ,Cavity wall - Abstract
An in-house developed code, Sofie, and the methods used for numerical determination of the ionization efficiency of thermal ionization cavity (TIC) sources up to intermediate temperatures (\textless2500 K for cavity dimensions of a few millimetres) are presented, thus, creating a tool to identify cavity geometries offering better ionization efficiencies and to aid in matching the ion beam produced by a TIC source to the ion optics of a beam line or a mass analyser as used in conventional thermal ionization mass spectrometry (TIMS). Essential is the code's ability to approximate the solution of Poisson's equation, in which the space charge predominantly originates from electrons thermally emitted from the inner cavity walls. The assumption of a quasi-neutral plasma forming in the volume of the cavity is no longer valid at lower temperatures and/or cavity dimensions, and charged particles can be regarded as moving freely throughout the cavity only interacting via the electrostatic potential shaped by the particles' space charge. Under such conditions the geometry of the cavity has got a large effect on the ionization efficiency of sample atoms loaded into the source. The code also allows the simulation of surface adsorption and re-emission of various particle species simultaneously, making the calculation of ionization efficiencies possible by determining the currents of sample ions and neutral atoms out of the cavity. The validity of the code is successfully demonstrated by simulating problem sets, for which analytical solutions exist, and also by reproducing experimental data from TIC sources found in the literature. The necessity of including space charge in such simulations is demonstrated. A non-exhaustive search for a best cavity geometry has been performed and a geometry has been identified that could enhance the ionization efficiency by up to a factor of 100 over the ionization efficiency of the Saha-Langmuir equation, which corresponds to the efficiency achievable with conventional flat filament TIMS sources. (C) 2016 Elsevier B.V. All rights reserved.
- Published
- 2016
45. The building blocks of Earth and Mars: A close genetic link
- Author
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Xueying Wang, Caroline Fitoussi, Bernard Bourdon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010502 geochemistry & geophysics ,01 natural sciences ,Astrobiology ,Physics::Geophysics ,building blocks ,Geochemistry and Petrology ,Chondrite ,Planet ,0103 physical sciences ,Earth and Planetary Sciences (miscellaneous) ,Composition of Mars ,010303 astronomy & astrophysics ,Achondrite ,Refractory (planetary science) ,isotopes ,0105 earth and related environmental sciences ,Mars composition ,Mars Exploration Program ,Earth composition ,planetary formation ,Geophysics ,Meteorite ,13. Climate action ,Space and Planetary Science ,[SDU]Sciences of the Universe [physics] ,Physics::Space Physics ,terrestrial planet's recipe ,Astrophysics::Earth and Planetary Astrophysics ,Earth (classical element) ,Geology - Abstract
The Earth formed in a swarm of Moon- to Mars-sized objects that collided together to build our planet. A large body of work has been dedicated to understanding the Earth's composition as being made of single groups or mixtures of chondrites, however, these models cannot account for the isotopic and elemental characteristics of the Earth. Here, we test mixtures of meteorites, including achondrites, analyzed for seven isotope systems (O, Cr, Ni, Ti, Mo, Ca and Sr), to reproduce the isotope compositions of the Earth and Mars. Our Monte Carlo inversion (a numerical method based on generation of random numbers used to invert multiparameter models) yields a new compositional model where Earth and Mars come almost entirely from the same source material. This finding is in striking agreement with recent planetary formation models in which Earth and Mars formed in a common narrow zone of the protoplanetary disk with Mars being ejected to its current position which prevented further accretion. An important outcome of the model is that a significant mass fraction of the Earth could have been made of volatile depleted and refractory enriched planetary bodies such as angrites (among the oldest known achondrites). This conclusion is also in agreement with new Si isotope data in angrites which suggest that a component of angrites would help explain the difference in delta Si-30 between the bulk silicate Earth and its building blocks. Our model matches all isotope compositions for both planets, reproduces the volatile element budget of Mars, and accounts for the enrichment in refractory elements of the Earth and Mars compared to chondrites. (C) 2015 Elsevier B.V. All rights reserved.
- Published
- 2016
46. Experimental evidence for the absence of iron isotope fractionation between metal and silicate liquids at 1GPa and 1250–1300°C and its cosmochemical consequences
- Author
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Max W. Schmidt, Remco C. Hin, and Bernard Bourdon
- Subjects
Stable isotope ratio ,Radiochemistry ,Analytical chemistry ,Fractionation ,Mass-independent fractionation ,Silicate ,Equilibrium fractionation ,chemistry.chemical_compound ,Isotope fractionation ,chemistry ,Geochemistry and Petrology ,Chondrite ,Mineral redox buffer ,Geology - Abstract
Iron isotope fractionation during metal–silicate differentiation has been proposed as a cause for differences in iron isotope compositions of chondrites, iron meteorites and the bulk silicate Earth. Stable isotope fractionation, however, rapidly decreases with increasing temperature. We have thus performed liquid metal–liquid silicate equilibration experiments at 1250–1300 °C and 1 GPa to address whether Fe isotope fractionation is resolvable at the lowest possible temperatures for magmatic metal–silicate differentiation. A centrifuging piston cylinder apparatus enabled quantitative metal–silicate segregation. Elemental tin or sulphur was used in the synthetic metal-oxide mixtures to lower the melting temperature of the metal. The analyses demonstrate that eight of the 10 experimental systems equilibrated in a closed isotopic system, as was assessed by varying run durations and starting Fe isotope compositions. Statistically significant iron isotope fractionation between quenched metals and silicates was absent in nine of the 10 experiments and all 10 experiments yield an average metal–silicate fractionation factor of 0.01 ± 0.04‰, independent of whether graphite or silica glass capsules were used. This implies that Fe isotopes do not fractionate during low pressure metal–silicate segregation under magmatic conditions. In large bodies such as the Earth, fractionation between metal and high pressure (>20 GPa) silicate phases may still be a possible process for equilibrium fractionation during metal–silicate differentiation. However, the 0.07 ± 0.02‰ heavier composition of bulk magmatic iron meteorites relative to the average of bulk ordinary/carbonaceous chondrites cannot result from equilibrium Fe isotope fractionation during core segregation. The up to 0.5‰ lighter sulphide than metal fraction in iron meteorites and in one ordinary chondrite can only be explained by fractionation during subsolidus processes.
- Published
- 2012
47. Solution Speciation Controls Mercury Isotope Fractionation of Hg(II) Sorption to Goethite
- Author
-
Bernard Bourdon, Ruben Kretzschmar, Martin Jiskra, and Jan G. Wiederhold
- Subjects
Minerals ,Goethite ,Isotope ,Inorganic chemistry ,Sorption ,Mercury ,General Chemistry ,Equilibrium fractionation ,chemistry.chemical_compound ,Spectrometry, Fluorescence ,Isotope fractionation ,Adsorption ,Isotopes ,X-Ray Diffraction ,chemistry ,Environmental chemistry ,visual_art ,Kinetic isotope effect ,visual_art.visual_art_medium ,Environmental Chemistry ,Sulfate ,Iron Compounds - Abstract
The application of Hg isotope signatures as tracers for environmental Hg cycling requires the determination of isotope fractionation factors and mechanisms for individual processes. Here, we investigated Hg isotope fractionation of Hg(II) sorption to goethite in batch systems under different experimental conditions. We observed a mass-dependent enrichment of light Hg isotopes on the goethite surface relative to dissolved Hg (ε(202)Hg of -0.30‰ to -0.44‰) which was independent of the pH, chloride and sulfate concentration, type of surface complex, and equilibration time. Based on previous theoretical equilibrium fractionation factors, we propose that Hg isotope fractionation of Hg(II) sorption to goethite is controlled by an equilibrium isotope effect between Hg(II) solution species, expressed on the mineral surface by the adsorption of the cationic solution species. In contrast, the formation of outer-sphere complexes and subsequent conformation changes to different inner-sphere complexes appeared to have insignificant effects on the observed isotope fractionation. Our findings emphasize the importance of solution speciation in metal isotope sorption studies and suggest that the dissolved Hg(II) pool in soils and sediments, which is the most mobile and bioavailable, should be isotopically heavy, as light Hg isotopes are preferentially sequestered during binding to both mineral phases and natural organic matter.
- Published
- 2012
48. Seasonal sensitivity of weathering processes: Hints from magnesium isotopes in a glacial stream
- Author
-
Bernard Bourdon, Edward T. Tipper, Ben C. Reynolds, Ruth S. Hindshaw, and Emmanuel Lemarchand
- Subjects
geography ,geography.geographical_feature_category ,Isotope ,Drainage basin ,Geochemistry ,Geology ,Weathering ,Fractionation ,Silicate ,chemistry.chemical_compound ,chemistry ,Geochemistry and Petrology ,Environmental chemistry ,Precipitation ,Leaching (agriculture) ,Isotopes of magnesium - Abstract
Seasonal changes in river chemistry offer the potential to assess how weathering processes respond to changing meteorological parameters and ultimately how chemical weathering might respond to climatic parameters. Systematic seasonal variations in magnesium isotope ratios (the 26Mg/24Mg ratio expressed as δ26Mg in per mil units) are reported in stream waters from a mono-lithological granitic, weathering-limited, first order catchment from the Swiss Alps (Damma glacier). Rain, ground, and pore-waters, in addition to plants, rocks, mineral separates and soil are also reported. The concentration response of the river waters is attenuated compared to the large changes in discharge. However, the systematic trends in the isotope data imply that either the source of the Mg changes in a systematic manner, or that the process by which Mg is released into solution changes as a function of discharge. The two first order observations in the data that need to be explained are 1) the systematic enrichment in 24Mg in the stream waters compared to the granitic rocks they drain and 2) a systematic increase in δ26Mg in the waters during the summer melt season. Both observations (which are similar to many other rivers draining silicate rock) can either be accounted for by 1) conservative mixing between at least two different sources of Mg (in addition to precipitation inputs), or 2) process related fractionation. If the stream water compositions can be rationalised by multi-component mixing, there is at least one unidentified component with a δ26Mg < − 1.2‰. This is considered unlikely. Multiple physicochemical processes could fractionate Mg isotope ratios such as 1) preferential leaching of 24Mg, 2) exchange of Mg onto (or from) mineral surfaces and into interlayer sites of clays, 3) uptake by plants, and 4) 26Mg could be preferentially retained during the formation of secondary phases, such as clays, amorphous phases or oxides. These processes are not mutually exclusive and distinguishing between them at a field scale is not trivial, but significant biological uptake is improbable at this site. Unless there is a non-identified external input of Mg, 26Mg must be accumulating in solid phase residues in the catchment because of at least one physicochemical process. Such processes are likely well described, at least in the first order by a Rayleigh distillation model. Simple calculations illustrate how much 26Mg would accumulate in the catchment per unit time. In the first order, the isotopic enrichments in the solids are so small that they would not be detectable for the time-scales that are relevant to this field site, in spite of the marked impact on the water chemistry. The seasonal signal detected by Mg isotope ratios is promising for using them (with a better understanding of fractionation mechanisms) to quantify how specific weathering processes impact upon both export fluxes, and retention of elements within catchments.
- Published
- 2012
49. Refractory element fractionation in the Allende meteorite: Implications for solar nebula condensation and the chondritic composition of planetary bodies
- Author
-
Bernard Bourdon, Carsten Münker, Andreas Stracke, Detlef Günther, Marko Gellissen, Jutta Zipfel, Thorsten Kleine, Karin Birbaum, Herbert Palme, Institute of Geochemistry and Petrology, Institut für Mineralogie, Westfälische Wilhelms-Universität Münster (WWU), Senckenberg Forschungsinstitut und Naturmuseum, Naturmuseum Frankfurt, Institut für Geologie und Mineralogie [Köln], Universität zu Köln, Institut für Planetologie [Münster], Laboratory of Inorganic Chemistry, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Forderungsprofessur of the Schweizerischer Nationalfonds : PP00P2_123470, Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Westfälische Wilhelms-Universität Münster = University of Münster (WWU), Universität zu Köln = University of Cologne, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
RARE-EARTH-ELEMENTS ,ID-ICP-MS ,CHEMICAL FRACTIONATIONS ,[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] ,[SDE.MCG]Environmental Sciences/Global Changes ,Mineralogy ,[PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] ,010502 geochemistry & geophysics ,01 natural sciences ,ASTEROIDAL ALTERATION ,Parent body ,CV3 CHONDRITES ,Allende meteorite ,[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry ,Geochemistry and Petrology ,Chondrite ,0103 physical sciences ,TRACE-ELEMENTS ,CARBONACEOUS CHONDRITES ,LU-HF ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Rare-earth element ,Refractory metals ,Chondrule ,CA-RICH INCLUSIONS ,TERRESTRIAL PLANETS ,Meteorite ,13. Climate action ,Formation and evolution of the Solar System ,Geology - Abstract
International audience; Chondritic meteorites represent primitive undifferentiated solar system material that is compositionally similar to the nonvolatile fraction of the Sun. The mineralogy and texture of chondritic meteorites is complex, however, because they are mixtures of several components that formed under different conditions in the solar nebula and were further processed on their parent bodies: chondrules, a volatile rich, fine-grained matrix, including a variety of mineral and lithic clasts, metal, sulfides, and Ca, Al-rich inclusions (CAI). The bulk chemistry of a single aliquot of a chondritic meteorite consequently depends on the size and distribution of its constituents. Here, we investigate the effect of sample heterogeneity on the major and trace element composition of the CV chondrite Allende using a single 30 g slice, which is 22.5 cm(2) in dimension and 4 mm thick. Thirty-nine equally sized pieces with an average sample weight of ca. 0.6 g (corresponding to a cube with an edge length of 5 to 6 mm) were powdered and aliquots of 0.12 g and 0.02-0.03 g were analyzed by XRF for major and ICP-MS for trace elements. One sample contained a large CAI, another sample was dominated by a dark inclusion (DI). Excluding these two samples, the concentrations of the major elements Mg, Si and Fe are constant within analytical uncertainty at the millimeter-centimeter scale (S.D. 0.9, 1.3 and 2.6%, respectively). Non-refractory minor and trace elements are similarly constant, including geochemically very different elements such as Mn, Cr, Ni, Co, P, Zn and Pb. This reflects a uniform mixture of the various host phases of these elements during accretion, and excludes elemental redistribution above a millimeter-scale by aqueous alteration and/or thermal metamorphism on the parent body. The refractory elements Al, Ca, Ti etc. are more variable (S. D. 17, 10 and 9%, respectively), which is mainly the result of different proportions of millimeter-size CAI, many of them with strongly fractionated group II rare earth element patterns, i.e., variable enrichment of the more volatile refractory elements (Ta, U, Nb, Sr, Tm, Nd) over the strongly refractory elements (Lu, Zr, Hf). Admixture of group II CAI can also account for the sub-chondritic Nb/Ta and Zr/Nb ratios in CV chondrites. The total average of all 37 samples has a clear group II-type rare earth element pattern. If this fractionated refractory element pattern is representative of the Allende parent body, this observation suggests that bulk planetary bodies, possibly including the Earth-forming planetary embryos, may have refractory element patterns that are fractionated relative to those of CI chondrites.
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- 2012
50. The influence of source heterogeneity on the U–Th–Pa–Ra disequilibria in post-glacial tholeiites from Iceland
- Author
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Janne M. Koornneef, Karl Grönvold, Bernard Bourdon, Andreas Stracke, and Geology and Geochemistry
- Subjects
Basalt ,geography ,Incompatible element ,Rift ,geography.geographical_feature_category ,Trace element ,Geochemistry ,Mineralogy ,Mantle (geology) ,Plume ,Volcano ,Geochemistry and Petrology ,Upwelling ,SDG 14 - Life Below Water ,Geology - Abstract
We investigate the relative influence of mantle upwelling velocity and source heterogeneity on the melting rates recorded by 230 Th– 238 U, 231 Pa– 235 U and 226 Ra– 230 Th disequilibria in post-glacial tholeiites from Iceland’s main rift areas. The measured ( 230 Th/ 238 U) ratios range from 1.085 to 1.247, the ( 231 Pa/ 235 U) ratios from 1.333 to 1.925, and the ( 226 Ra/ 230 Th) ratios from 0.801 to 1.218. A general positive correlation between 230 Th excesses and distance from the inferred plume centre is consistent with a model of decreasing mantle upwelling velocity with increasing distance from the plume axis. However, the model is not substantiated by the ( 231 Pa/ 235 U) data as the correlation with distance from the plume centre is weak. On the scale of individual eruption centres, the observed U-series are influenced by variations in melt transport time, source porosity, and local variations in mantle upwelling velocity. Broad correlations between ( 230 Th/ 238 U) and ( 231 Pa/ 235 U) and highly incompatible trace element ratios for samples from the Western Volcanic Zone provide, however, evidence for a significant underlying effect of source heterogeneity on the U-series data. Low 230 Th and 231 Pa excesses in enriched samples from the Western Volcanic Zone with high U/Th, Nb/U and Nb/La indicate that partial melts from an enriched source component, characterised by high melt productivity but low bulk D U / D Th , influence the U-series systematics of the erupted melts. These results re-affirm the presence of comparatively larger abundances of enriched material in the mantle source beneath the South Western Rift of Iceland, which has been suggested based on relationships between highly incompatible element and Pb isotope ratios in Icelandic basalts. Overall, our results highlight the importance of lithological heterogeneity on the melting behaviour of the upper mantle and the composition of oceanic basalts.
- Published
- 2012
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