A5033991471- Geological and Geochemical Analysis
- Hydrocarbon exploration and reservoir analysis
- Radioactive element chemistry and processing
- Geochemistry and Geologic Mapping
- Geochemistry and Elemental Analysis
- High-pressure geophysics and materials
- Methane Hydrates and Related Phenomena
- Metal Extraction and Bioleaching
- Extraction and Separation Processes
- Minerals Flotation and Separation Techniques
- Mineralogy and Gemology Studies
- Phase Equilibria and Thermodynamics
- Inorganic Fluorides and Related Compounds
- X-ray Spectroscopy and Fluorescence Analysis
- Iron oxide chemistry and applications
- Glass properties and applications
- Paleontology and Stratigraphy of Fossils
- Atmospheric and Environmental Gas Dynamics
- Radioactivity and Radon Measurements
- Refrigeration and Air Conditioning Technologies
- Chemical Thermodynamics and Molecular Structure
- Radioactive contamination and transfer
- Industrial Engineering and Technologies
- Mining and Gasification Technologies
- Groundwater and Isotope Geochemistry
Institut des Sciences de la Terre d'Orléans
2012-2024
Centre National de la Recherche Scientifique
2014-2024
University of Münster
2020-2023
Institut des Sciences de la Terre
2012-2023
Université d'Orléans
2023
Deutsches Elektronen-Synchrotron DESY
2021
GFZ Helmholtz Centre for Geosciences
2021
University of Bristol
2017-2020
University of Cambridge
2019
Université Grenoble Alpes
2014-2017
Abstract Rare earth elements (REE), essential metals for the transition to a zero-emission economy, are mostly extracted from REE-fluorcarbonate minerals in deposits associated with carbonatitic and/or peralkaline magmatism. While role of high-temperature fluids (100 < T 500 °C) development economic concentrations REE is well-established, mechanisms element transport, ore precipitation, and light (L)REE/heavy (H)REE fractionation remain matter debate. Here, we provide direct evidence...
Earth's deep carbon cycle affects atmospheric CO2, climate, and habitability. Owing to the extreme solubility of CaCO3, aqueous fluids released from subducting slab could extract all slab. However, recycling efficiency is estimated at only around 40%. Data carbonate inclusions, petrology, Mg isotope systematics indicate Ca2+ in carbonates replaced by Mg2+ other cations during subduction. Here we determined dolomite [CaMg(CO3)2] rhodochrosite (MnCO3), put an upper limit on that magnesite...
A combined magneto-mineralogical approach is used to diagnose maghemitization in magnetic grains of basaltic rock fragments from sand dunes the Namibian desert SW Africa. Data were obtained static analysis, ferromagnetic resonance (FMR) spectroscopy, micro-Raman spectroscopy and electron microscopy. Micro-Raman showed that lithic form oxidative solid solution series with magnetite maghemite as end-members. The five active Raman modes at 712, 665, 507, 380 344 cm−1 indicate has well-defined...
Abstract Here we report the results of multiple analytical techniques on sub-mm particulate material derived from Unit 1 Fukushima Daiichi Nuclear Power Plant to provide a better understanding events that occurred and environmental legacy. Through combined x-ray fluorescence absorption contrast micro-focused tomography, entrapped U are observed exist around exterior circumference highly porous Si-based particle. Further synchrotron radiation analysis number these particles shows them as UO 2...
Zirconium and hafnium behave nearly identically in most geological processes due to their identical nominal ionic charge similar radius. Some of the pronounced exceptions from this rule are observed fluoride-rich aqueous systems, suggesting that fluoride complexation may be involved Zr/Hf fractionation. To understand mechanisms causing phenomenon, we investigated Zr4+ Hf4+ (1.0 mol/kg HF) solutions at 40 MPa 100 - 400 °C, using synchrotron X-ray absorption spectroscopy (X-ray near edge...
The partitioning of Zr between high P-T aqueous fluids and melts has been investigated in situ the haplogranite-H2O haplogranite-(F)-H2O systems to assess mobilization field strength elements (HFSE) magmatic-hydrothermal processes subduction zones. partition coefficients Df/Zmr were determined from concentrations measured by synchrotron X-ray fluorescence (SXRF) both F-free or F-bearing hydrous haplogranite equilibrated diamond-anvil cells at 575 800 °C 0.3 2.4 GPa. This experimental...
Abstract. Tungsten (W) concentrations in fluids equilibrium with crystalline tungsten oxide are used to determine thermodynamic parameters for W solubility and species hydrothermal fluids. The data were measured situ at high pressures temperatures using X-ray absorption. spectroscopic – absorption near-edge structure (XANES) extended fine (EXAFS) applied characterize the symmetry type of atoms first coordination shell aqueous complexes present fluid given pressures. Experiments performed up...
Rare Earth elements (REE) are gaining importance due to their increasing industrial applications and usefulness as petrogenetic indicators. REE-sulfate complexes some of the most stable REE aqueous species in hydrothermal fluids, may be responsible for transport deposition a wide variety geological environments, ranging from sedimentary basins magmatic settings. However, thermodynamic properties derived extrapolation ambient temperature data, since direct information on complexing under...
Vibrational spectroscopy is a fundamental tool to investigate local atomic arrangements and the effect of environment, provided that spectral features can be correctly assigned. This challenging in experiments simulations when double peaks are present because they have different origins. Fermi dyads common class such doublets, stemming from resonance excitation mode with overtone another. We new, efficient approach unambiguously characterize resonances density functional theory (DFT) based...
Chlorine is the most common ligand in geofluids, and one of important complexing agents for rare earth elements. The geometry thermodynamic properties La(III)-Cl complexes determined by previous experimental studies show inconsistency especially at temperature over 350 °C. Here, ab initio molecular dynamics (MD) simulations were employed to determine nature up 500 °C pressure 30 kbar. ground proofed situ X-ray absorption spectroscopy (XAS) results (400 bar, 25 °C). Both MD XAS an increase...
Abstract
A new diamond-anvil cell apparatus for in situ synchrotron X-ray diffraction measurements of liquids and glasses, at pressures from ambient to 5 GPa temperatures 1300 K, is reported. This portable setup enables monitoring the melting complex compounds determination structure properties melts under moderately high pressure temperature conditions relevant industrial processes magmatic Earth's crust shallow mantle. The device was constructed according a modified Bassett-type hydrothermal design...
Abstract The volcanic degassing of halogens, and especially the heavier Br I, received increased attention over last 20 years due to their significant effect on atmospheric chemistry, notably depletion stratospheric ozone. While melt composition halogen diffusion, solubility, or fluid-melt partitioning in crustal magma chambers has been thoroughly studied, structural controls incorporation silicate melts remain poorly known, with only few studies available simplified borosilicate...
We discuss the X-ray absorption spectroscopy (XAS) methods elaborated using high pressure and high-temperature autoclaves installed at FAME FAME-UHD beamlines. These are based on in situ acquisition of transmission fluorescence spectra hydrothermal fluids silicate melts enable derivation both solubility speciation information about metal complexes. The technological assets our described across a wide range experimental conditions spanning from different types fluids, liquid-like to...
Abstract. Understanding the behavior of halogens (Cl, Br, and I) in subduction zones is critical to constrain geochemical cycle these volatiles associated trace metals, as well quantify halogen fluxes atmosphere via volcanic degassing. Here, partitioning bromine between coexisting aqueous fluids hydrous granitic melts its speciation slab-derived have been investigated situ up 840 ∘C 2.2 GPa by synchrotron x-ray fluorescence (SXRF) absorption spectroscopy (XAS) diamond anvil cells. The...
We present a new autoclave that enables in situ characterization of hydrothermal fluids at high pressures and temperatures synchrotron x-ray radiation sources. The has been specifically designed to enable absorption spectroscopy with applications mineral solubility element speciation analysis complex compositions. However, other applications, such as Raman spectroscopy, high-pressure are also possible the autoclave. First experiments were run between 100 600 bars 25 °C 550 °C, preliminary...