Description du projet
L’origine volatile de la Terre révélée par des analyses isotopiques du krypton et du xénon
La composition des gaz nobles lourds krypton (Kr) et xénon (Xe) présents dans le manteau terrestre est mal comprise; c’est pourquoi l’histoire volatile de la Terre reste si largement méconnue. Le projet VolatileOrigin, financé par l’UE, mesurera avec précision les isotopes Kr et Xe dans des échantillons dérivés du manteau, y compris les basaltes et les diamants de la dorsale médio-océanique, et dans différents types de météorites. En déterminant les compositions d’échantillons de la dorsale médio-océanique et de diamants, les chercheurs pourront caractériser l’étendue des hétérogénéités mantelliques de Kr et Xe, introduites par le recyclage progressif des gaz rares atmosphériques par subduction, et ainsi identifier la ou les sources de ces volatils dans le manteau. Des données précises concernant les isotopes Kr et Xe non radiogéniques dans les météorites permettront de mieux comprendre les compositions mesurées du manteau et d’identifier les sources volatiles.
Objectif
The presence of volatile elements such as carbon, nitrogen, water, noble gases, on terrestrial planets is a requirement for planet habitability, yet their origin is still highly debated. Noble gases are invaluable tracers of volatile sources due to their inertness, in particular their non-radiogenic isotopes have kept remnant signatures of planetary accretion. Krypton and xenon are mighty tools to distinguish between chondritic and solar volatile sources due to the distinct isotopic compositions of these end-members. However, the heavy noble gas (Kr, Xe) compositions of the Earth’s mantle is poorly determined. Hence, the Earth’s mantle volatile history remains largely unknown. The objectives of this project are to precisely measure the non-radiogenic Kr and Xe isotopes in mantle-derived samples, including mid-ocean ridge basalts and diamonds, and in meteorites of different types in order to better understand Earth’s volatile origin. Determining the compositions of mid-ocean ridge and diamond samples will allow to characterize the extent of mantle Kr and Xe heterogeneities, introduced through progressive atmospheric noble gas recycling via subduction, and, hence to identify the source(s) of these volatiles in the mantle. Precise bulk meteorite data for the non-radiogenic Kr and Xe isotopes are incomplete and will be crucial in our understanding of the measured mantle compositions to fingerprint the volatile sources. This project will use a novel protocol for the specific measurements of these isotopes in mantle-derived samples associated with noble gas mass spectrometry. The MSCA fellowship represents a unique opportunity for me to learn new analytical skills in cosmochemistry, to improve my soft skills and to secure my fruitful reintegration in Europe. I will transfer to the host lab my expertise of mantle geochemistry. On the whole, this project will strengthen my scientific independence, taking me closer to achieve an outstanding academic position in Europe.
Champ scientifique
- natural scienceschemical sciencesinorganic chemistrynoble gases
- natural sciencesphysical sciencesastronomyplanetary sciencesmeteorites
- natural sciencesphysical sciencesastronomyplanetary sciencesplanets
- natural sciencesearth and related environmental sciencesgeochemistrycosmochemistry
- natural scienceschemical sciencesanalytical chemistrymass spectrometry
Mots‑clés
Programme(s)
Régime de financement
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinateur
8092 Zuerich
Suisse