A5019827486- Geochemistry and Elemental Analysis
- Geological and Geochemical Analysis
- Paleontology and Stratigraphy of Fossils
- Isotope Analysis in Ecology
- Astro and Planetary Science
- Radioactive element chemistry and processing
- Mercury impact and mitigation studies
- High-pressure geophysics and materials
- earthquake and tectonic studies
- Geochemistry and Geologic Mapping
- Analytical chemistry methods development
- Planetary Science and Exploration
- Rare-earth and actinide compounds
- Hydrocarbon exploration and reservoir analysis
- Geology and Paleoclimatology Research
- Mass Spectrometry Techniques and Applications
- Groundwater and Isotope Geochemistry
- Chemical Thermodynamics and Molecular Structure
- Astronomical and nuclear sciences
- Inorganic Chemistry and Materials
- Pacific and Southeast Asian Studies
- Radioactive contamination and transfer
- Magnetic and transport properties of perovskites and related materials
- Metallurgical Processes and Thermodynamics
- Radioactive Decay and Measurement Techniques
Laboratoire Magmas et Volcans
2018-2023
Centre National de la Recherche Scientifique
2012-2023
Université de Bretagne Occidentale
2021-2023
Université Clermont Auvergne
2018-2023
Institut de Recherche pour le Développement
2019-2023
Ifremer
2023
Institut Universitaire Européen de la Mer
2021-2023
Geo-Ocean
2021
University of Oxford
2015-2020
The Open University
2011-2015
Chromium isotopes are fractionated during redox reactions and have the potential to provide a record of changes in oxygenation levels oceans geological past. However, Cr is trace metal seawater its low concentrations make isotopic measurements challenging. Here we report first determinations δCr53 for from open ocean (Argentine Basin) coastal (Southampton Water) settings, using double-spike technique. The total chromium concentration Southampton Water 1.85 nM, whereas content Argentine Basin...
Techniques for the separation of small quantities Cr from carbonate material and analysis stable isotopes in carbonates by MC-ICP-MS are presented this study. In comparison with previously published methods, we have developed a one-step procedure that is relatively simple, has low blank (0.12–0.20 ng). Moreover, careful optimisation desolvating sample introduction system allows significant increase sensitivity our technique compared to previous studies. Instrumental mass bias effects...
We present new mass independent and dependent Cr isotope compositions for meteorites measured by double spike thermal ionisation spectrometry. Small differences in both 53Cr 54Cr relative to the Bulk Silicate Earth are reported very similar previously published values. Carbonaceous chondrites characterised an excess compared ordinary enstatite which make isotopes a useful tool distinguishing between meteoritic groups. Mass stable same samples also reported. identical within uncertainty with...
We present the first stable chromium isotopic data from mare basalts in order to investigate similarity between Moon and Earth's mantle. A double spike technique coupled with MC-ICP-MS measurements was used analyse 19 basalts, comprising high-Ti, low-Ti KREEP-rich varieties. Chromium isotope ratios (δ53Cr) for are positively correlated indices of magmatic differentiation such as Mg# Cr concentration which suggests that isotopes were fractionated during differentiation. Modelling results...
Precambrian banded iron formations (BIF) are chemical sedimentary deposits whose trace element signatures have been widely used to interrogate the composition and redox state of ancient seawater. Here we investigated in BIF 3.22 Ga Moodies Group, Barberton Greenstone Belt (South Africa), which interbedded with near-shore siliciclastic rocks represent one oldest known shallow-water occurrences BIF. Unusual rare earth (REE) signatures, notably pronounced negative Ce anomalies shale-normalized...
Techniques for the separation of Cerium (Ce) from silicate matrices and analysis radiogenic (<italic>ε</italic><sup>138</sup>Ce) mass dependent (<italic>δ</italic><sup>142</sup>Ce) Ce isotope variations by Thermal Ionisation Mass Spectrometry (TIMS) are presented in this study.
Data on the chromium stable isotope composition of planetary reservoirs have potential to provide information about core formation, partial melting and conditions Moon formation. In order detect small Cr isotopic differences between various in solar system, their compositions need be precisely constrained. The current BSE value δ53Cr = −0.11 ± 0.06‰ (Sossi et al., 2018) cannot resolve achondrites, (Vesta −0.17 0.05‰) chondrites (carbonaceous −0.12 0.05‰; ordinary 0.04‰). bulk silicate Earth...
Chromium isotope compositions have been determined for 42 mantle-derived xenoliths from Cameroon, France, Mongolia, Russia and the USA. The samples are mainly spinel garnet lherzolites, or harzburgites, yield δ53CrNIST979 −0.33 to 0.43‰, within range of previously reported compositions, −0.51 0.74‰ (Xia et al., 2017). Partial melting has proposed as a process that alters δ53Cr mantle residue. New non-modal models show compatible nature Cr is inconsistent with large changes in residue's...
Abstract Hot spot lavas show a large diversity of isotope compositions resulting from the recycling surface material into convective mantle. Amongst mantle end‐members, EM‐1 (enriched mantle) is widely debated and scenarios involving either old pelagic sediments subducted deep or subcontinental lithospheric incorporated at shallow depths are commonly evoked. We selected 12 Gough Island (south Atlantic Ocean) for measurement 138 La‐ Ce, 147 Sm‐ 143 Nd, 176 Lu‐ 177 Hf systems. Results limited...
Ce (‰) Ce/Ce* Silicate rocks Carbonates BIF 1.2 0.6 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 Nodules 1.4 NOD-A1 = 4.18 1.6 Oxidation No oxidation Negative anomaly 1.8Redox conditions in past oceans have attracted significant interest and many proxies been used to probe redox changes through time.For example, the dependent behaviour of Ce, resulting negative or positive elemental anomalies, has widely used.More recently, mass isotopic variations proposed as a powerful tool study...
A 600 km long metabasite belt is exposed at the southern border of Chugach terrane in Alaska, south Eocene Metamorphic Complex (CMC). In this contribution, we present petrologic and geochemical results for parts belt. The metabasites studied are amphibolite grade their PT conditions evaluated with hornblende–plagioclase thermometry average method. From west to east peak metamorphic calculated are: about 730–793 °C pressures between 5 15 kbar westernmost part, 740–760 middle locality 640–675...
The coupling of a micro-flow injection sample introduction system to highly versatile quadrupole ICP-MS (FI-ICP-MS) has been demonstrated achieve accurate and precise trace element measurements for several iron meteorites.
Abstract The ca. 3.5 Ga Bon Accord Ni deposit was located in the Barberton Greenstone Belt of Kaapvaal Craton, South Africa, and contained a unique assemblage Ni-rich minerals including trevorite (NiFe2O4). It initially interpreted as metamorphosed extraterrestrial body, recently ruled out by Cr isotope data, subsequently fragment Archean Earth’s core. More recent suggestions have highlighted similarities between magmatic sulfide mineralization. We present geochemical (rare earth element...