FOREVER · Formation and Evolution of the Earth with Volatile Elements

The first 150 million years of the Earths history have led to the formation of the metallic core and the solidification of the magma ocean. During this period the chemical composition of the core and the bulk silicate Earth (BSE) were defined, setting the initial conditions for subsequent planetary-scale evolution. The volatile and atmophile elements (C, H, N, O, S) and noble gases (used as tracers) compose life molecules and control key atmospheric properties, thus contributing to the definition of habitable planets. These elements are abundant at the Earths surface but the planetary interior represent a much greater reservoir. Determining C, H, N, O, S and noble gases budget in both the core and the BSE requires experimental data at the deep magma ocean conditions, which is currently challenging. However, this information is critical for interpreting geophysical and geochemical observations on the distribution and cycling of volatile compounds. Here, we will conduct laboratory experiments to quantify the concentrations of these elements (into the core and the BSE) at the conditions that prevailed during core formation. We also aim to establish how the main phases of the lower mantle controlled the volatile budget during and immediately after magma ocean times by measuring the in-situ electrical and seismic profiles of volatile-bearing minerals. The quantitative constraints from our experimental studies will then be incorporated within innovative numerical convection models to determine the effect of volatiles on the thermal, rheological and melt fraction evolution of a cooling and crystallizing magma ocean, and also on the evolution of the primordial atmosphere of planets. Finally, these experimental constraints will be combined with geochemical and cosmochemical ones to build a new generation of models in which the formation of Earth and its atmosphere is viewed within a realistic context of the formation and evolution of our solar system.