Fe oxidation state in dense liquid silicates probed by XAS under dynamic compression

The present proposal aims at determining Fe oxidation state and local environment in dense (Mg,Fe)SiO3 liquids, but also the stability of these liquids against demixing of liquid metallic iron at planetary interior conditions. By determining these parameters as a function of pressure, temperature and concentration of Fe in both liquids and glasses, we expect to constrain the processes involved in the segregation of an iron-rich core from a silicate magma ocean and in the degassed atmosphere chemistry during the formation of terrestrial planets. (Mg,Fe)SiO3 liquids will be investigated by XAS coupled to laser-driven dynamic compression on the HPLF platform on ID24-ED beamline. In addition, XAS investigation of statically compressed glasses of similar composition at room temperature in DAC will be performed on BM23 beamline in order to have a good benchmark and support for the shock experiment thanks to a large EXAFS range, higher energy resolution and better signal to noise ratio.