Description du projet
Le traçage des éléments halogènes dans les météorites offre un nouvel éclairage sur la formation de la Terre
L’évolution physique et chimique de la Terre et le développement de la vie à sa surface dépendent d’éléments volatils comme les halogènes. Des questions fondamentales concernant la façon dont la Terre a acquis ses éléments volatils, la période où elle l’a fait et leur répartition au sein de ses réservoirs géochimiques demeurent sans réponse. Le projet HAMA, financé par l’UE, cherchera à mieux comprendre la géochimie des halogènes en mesurant la concentration d’éléments tels que le fluor, le chlore, le brome et l’iode dans un groupe hétérogène de météorites primitives. Ces météorites sont susceptibles d’avoir figuré parmi les constituants essentiels ayant favorisé la formation de la Terre. Les recherches menées dans le cadre du projet mettront en évidence le comportement des halogènes entraînés dans le manteau terrestre par un mouvement de subduction ainsi que leur influence sur la chimie des magmas et sur le volcanisme.
Objectif
Halogens (F, Cl, Br and I) are involved in key processes of the Earth and Planetary sciences. However, some crucial challenges of halogens’ geochemistry are unsolved. They include (i) halogen abundances in the Earth’s primitive mantle (PM) with implications on their origin and evolution during Earth formation and early differentiation; (ii) their behaviour during subduction to the Earth’s mantle; and (iii), their magmatic-volcanogenic fluxes from the mantle to the crust at subduction zones (SZ). Halogen geochemistry is currently hampered by analytical and sampling limitations. The suitability of reference halogen values in glass standards for in situ analysis is disputed. It has been also shown that indirect inferences from the whole-rock compositions of magmas are limited for fully assessing the chemical geodynamics of halogens. Technique and methodology leaps are needed to allow the in situ analysis (i.e. in minerals) of mantle and crust rocks, and to address fundamental questions in halogen geochemistry. I propose to analyse halogens in the minerals of meteorites, and unique PM-like intraplate, SZ and cratonic mantle rocks. This research will enable to define new benchmark values for meteorites and PM and determine how halogens are recycled to SZ magmas and to the deeper mantle. I will produce new standards, which in combination with analytical developments, will provide unique data about the volumetrically important mantle reservoir. In the final phase of the project, I will study halogens in the mineral-hosted melt inclusions of magma-percolated mantle and crust rocks to derive partitioning coefficients and model their SZ magmatic-volcanogenic fluxes. The research will settle in an interdisciplinary, collaborative network to stimulate breakthrough outcomes in geochemistry, cosmochemistry, volcanology and economic geology. It will significant upgrade my technical and scientific capabilities and will allow me to reach a leading position in volatile geochemistry.
Champ scientifique
- natural sciencesphysical sciencesastronomyplanetary sciencesmeteorites
- natural sciencesearth and related environmental sciencesgeologyvolcanology
- natural sciencesearth and related environmental sciencesgeologyseismologyplate tectonics
- natural scienceschemical sciencesinorganic chemistryhalogens
- natural sciencesearth and related environmental sciencesgeochemistrycosmochemistry
Mots‑clés
Programme(s)
Régime de financement
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinateur
1015 LAUSANNE
Suisse