Redox and Partitioning in Magma Oceans: From Melt Properties to Cooling Histories

Objective

Planetary magma oceans represent a defining stage of rocky planet evolution, where redox processes and element partitioning set the trajectory for mantle composition, cooling, and volatile distribution. Yet the extent of FeO disproportionation, the resulting ferric iron ratio, and the partitioning of key elements (Fe, H, and C) during crystallization remain poorly constrained, particularly under lower-mantle conditions. This project, REPAMO, will establish a multi-scale computational framework to quantify depth-dependent redox states and their control on melt properties, melting relations, and element partitioning. Ab initio molecular dynamics (AIMD) combined with thermodynamic integration will quantify ferric iron ratios in the magma ocean from the disproportionation reaction and determine partition coefficients of Fe, H, and C during crystallization. These AIMD datasets will be used to train machine-learning interatomic potentials, which will extend accuracy to large-scale two-phase coexistence simulations. This will enable direct extraction of element distributions, melt properties, and liquidus relations during crystallization. Finally, these results will be integrated into models of magma ocean cooling to predict crystallization pathways and redox-dependent thermal histories of terrestrial planets. The project supports Horizon Europe's Strategic Plan (2025–2027) on planetary formation, volatile cycles, and habitability (Cluster 4, Destination 5), and will provide predictive datasets directly relevant to ESA missions such as EnVision and ARIEL, as well as exoplanetary modeling efforts.