Thermodynamic modelling of melting in the system FeO-MgO-SiO2-O2 at pressure of 1 bar.

Using experimental data on solidus and liquidus phase relations, mixing parameters for the liquid phase in the system FeO-MgO-SiO2-O2 are assessed. P-x phase diagrams for olivine, pyroxene and magnesiowustite compositions and liquidus phase diagrams at different oxygen fugacities are calculated and compared with available experimental data. The agreement between calculated and experimental data are acceptable. However, new experimental data on olivine + magnesiowustite + liquid equilibrium in presence of iron are necessary to check if there is minimum in silica content for this equilibrium. High temperature data on solidus and liquidus of magnesiowustite could also provide key additional information necessary to refine the assessment.