Predicted (a and b) compositional and (c) density profiles of the initial solid mantle (i.e., after MO crystallization and prior to overturn), for bulk planet compositions of 8 wt% FeO and mantle molar Mg/Si ranging from 0.5 to 2.0. Compositional profiles are reported as molar ratios of Fe/(Mg + Fe) (a) and Si/(Mg + Si) (b). The density difference is between the crystallized solid, and pyrolite (i.e. Mg# = 0.88; see Eq. (2)). Crystallization proceeds from the bottom-up.