PhD student (M/F) - Metal activity in magmatic oceans

Descrizione

PhD student (M/F) - Metal activity in magmatic oceans Sintesi in italiano (traduzione automatica): Il laboratorio Magmas and Volcanoes (LMV) dell'Università Clermont Auvergne, in collaborazione con il CNRS e l'IRD, cerca un dottorando per un progetto sulla modellazione termodinamica degli oceani magmatici. La sede è situata nel campus universitario di Cézeaux ad Aubière. Il candidato lavorerà nel team di petrologia, interagendo con ricercatori e tecnici del laboratorio. Le mansioni principali includono lo sviluppo di un modello basato su esperimenti di laboratorio per descrivere le relazioni attività-composizione nei silicati fusi ad alta pressione. È richiesta una laurea in geoscienze o un campo correlato. La ricerca prevede anche collaborazioni con l'ESRF per analisi avanzate sui metalli nei magmi e applicazioni a pianeti terrestri e atmosfere di esopianeti. The Magmas and Volcanoes Laboratory (LMV) is a joint research unit of Clermont Auvergne University, affiliated with the French National Centre for Scientific Research (CNRS) and the French Research Institute for Development (IRD). It is situated on the Cézeaux university campus in Aubière. It is one of the two laboratories of the Clermont-Ferrand Observatory of Earth Physics. It has a staff of 82 permanent members (lecturers and researchers, research engineers and technicians, and administrative staff) and around 50 PhD students and postdoctoral researchers. The successful candidate will be assigned to the LMV's petrology team, which reports directly to the Director of the LMV. They will interact on a daily basis with members of the laboratory's three research teams (petrology, geochemistry, volcanology), with the engineers and technicians in charge of the laboratory's other analytical services, with the managers and the administrative manager, as well as with users from outside the laboratory. Metal activity in magmatic oceans We propose to develop a thermodynamic model of magmatic oceans on forming planets based on laboratory experiments. At present, high-pressure molten silicates are modelled only in a rudimentary manner, due to a lack of data on activity coefficients. In order to describe the activity–composition relationships in high-pressure molten silicates, our approach involves imposing an oxygen activity in the experiments using an electrochemical cell. This will enable us to determine the activities of the oxides comprising the liquid via the equilibrium: metal + oxygen = oxide. With a pure metal (activity = 1) and a known oxygen activity (set by the operator), the activity of the oxide will be calculated; comparison with the composition analysed in the quenched glasses after the experiment will enable us to extract the activity coefficients and develop a comprehensive model. A collaboration with the European synchrotron ESRF will enable us to determine the valence of metals in magmas. The magma ocean model will be applied, on the one hand, to the mantle-core equilibrium during the differentiation of terrestrial planets and, on the other hand, to the equilibria between the magma ocean and the primitive atmospheres of planets. In the latter case, we will be able to draw on new data on the atmospheres of exoplanets, for which recent instruments (ALMA, JWST) are providing increasingly precise information. Annuncio in inglese. Fonte: Euraxess (Commissione europea).