Estimated redox condition for each experiment. The range of oxygen abundance X_O (horizontal axis) for each starting material with the same SiO₂/(Si + SiO₂) ratio is calculated for the estimated inflow oxygen rates of 0.5 × 10⁻⁴ molmin⁻¹ (left edge) and 3.6 × 10⁻⁴ molmin⁻¹ (right edge). The redox condition becomes oxidizing with an increase in X_O. Even if the same starting material is used, the redox condition becomes more oxidized with a decrease in feeding rate, which is due to the relatively large contribution of the inflow oxygen. The redox condition (X_O) of each run is shown as a bar according to its starting material and feeding rate. The values of X_O for specific mineral assemblages expected from the GEMS composition are also shown for comparison.