more similar to enstatite chondrites [@Javo10], to mixtures of carbonaceous chondrites and ordinary chondrites [e.g. @Fito12]. We instead adopt the simplest model of a composition that is identical to the Sun in refractory elements, with an oxygen abundance fixed by the fO$_{2}$ of the condensing medium. For key moderately volatile elements such as Na, we assume an ad-hoc condensation efficiency of 26% to reproduce the Earth’s bulk Na composition [@Aspl05; @McD03].

![ Predicted phases (black) and densities (red) in this model (solid) compared to Earth reference compositions [dashed, @McD03]for (a) the bulk silicate Earth and (b) melt-extracted basalt as a function of pressure. The model mantle is calculated along a 1600 K adiabat while the basalt is calculated along a 1200 K adiabat. While the simplified model presented here does not reproduce the Earth in detail, it does reproduce the correct minerals and pressures of phase transitions and magnitude of density discontinuities. Our model mantle under predicts the olivine fraction in the mantle (55% vs. 60%) while our model basalt predicts clinopyroxene at the expense of garnet relative to average basalt compositions under predicting the density by no more than 3%. Garnet is the dense phase in the basalt-eclogite transition; 