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Sujet de recherche :
Modélisation prédictive de l'enrichissement en lithium dans les systèmes magmatiques-hydrothermaux
To better understand Li-Cesium-Tantalum (LCT) pegmatite formation, my PhD project aims to develop two tools; (1) create an internally consistent thermodynamic database of Li-bearing phases to forward model formation scenarios and (2) collect experimental partitioning data of trace elements and noble gasses in magmatic-hydrothermal systems to identify compositional features diagnostic of melt or fluid involvement. Thermodynamic modelling (1) is a powerful method for forward modelling of the behavior and enrichment of Li under varying physical and chemical conditions. As such, it is ideal to test the different proposed Li-enrichment scenarios. Unfortunately, there are two major barriers that hold back this approach: lack of thermodynamic data for Li phases and lack of consistency among existing data. I will address both and develop an internally consistent thermodynamic database for Li in aqueous, melt, and solid phases applicable to the full range of conditions encountered in natural systems. Additionally, understanding the behavior of trace elements and noble gases during LCT formation (2) can help locate Li-mineralization in the field. For instance, neutron capture of Li creates isotopic anomalies in the decay product He which can be applied to Li-pegmatite vectoring. By studying these anomalies in Li-bearing minerals, He isotope signatures can be used as indicators in the field.