Pressure Destabilizes Oxygen Vacancies in Bridgmanite

Bridgmanite may contain a large proportion of ferric iron in its crystal structure the forms FeFeO3 and MgFeO2.5 components. We investigated pressure dependence contents bridgmanite coexisting with MgFe2O4-phase or without ferropericlase MgO-SiO2-Fe2O3 ternary system at 2,300 K, 33 40 GPa. Together experiments 27 GPa reported Fei et al. (2020, https://doi.org/10.1029/2019GL086296), our results show that decrease from 7.6 to 5.3 mol % 2 3 nearly zero, respectively, increasing Accordingly, total Fe3+ decreases 0.18 0.11 pfu. The formation oxygen vacancies (MgFeO2.5 component) is therefore dramatically suppressed by pressure. Oxygen can be produced Fe3+-rich under topmost lower mantle conditions, but concentration should rapidly variation oxygen-vacancy content depth potentially affect physical properties thus dynamics.