## 4 Results and Discussion
### Temperature Sensitivity
However, contrary to the calculations above (Figures 2 and 3), if no solid phases are included in the calculation to constrain the solidus and all phases  
Figure 3: Temperature dependence of (**a**) phase fraction of L\({}_{\text{Fe}}\)-dispersed amoeboids and composition of (**b**) Fe-rich and (**c**) Si-rich liquids. Dashed curves correspond to analytical measurements from TEM and colors correspond to different components (FeO-red, SiO\({}_{2}\)-green, Al\({}_{2}\)O\({}_{3}\)-blue, CaO-orange, MgO-purple). other than the liquid phase are suspended, a small metastable region of two-phase liquid stability can be induced between 1120 \({}^{\circ}\)C \(<\) T \(<\) 1265 \({}^{\circ}\)C. While this can be used to provide some preliminary insight into compositional constraints of L\({}_{\text{Si}}\)-dispersed amoeboids, the metastable low-temperature range of formation provides an indication that non-equilibrium conditions are likely the contributing factor for amoeboid morphologies in the fallout glass. The calculations indicate that the predominant phase is predicted to be Fe-rich (Figure 4a), in agreement with experimental findings where the primary/matrix phase contains high levels of iron and the minor dispersed-phase is Si-rich. As temperature decreases in Figure 4a, the amount of Fe-rich liquid is reduced but remains dominant, and the Si-rich liquid increases in phase fraction. The composition of each liquid as a function of temperature is plotted in Figures 4b,c for the FeO and SiO\({}_{2}\)-rich liquids, respectively. The dashed lines are the experimentally observed compositions of each liquid phase based on TEM measurements and are inherently temperature independent. While the FeO content in Figure 4b is underestimated compared to experiments, we achieve reasonable agreement at temperatures around 1120 \({}^{\circ}\)C for most of the components in the Fe-rich liquid. The Si-rich liquid is calculated to be the minority phase (Figure 4a) and the predicted values for each component in this phase are computed in Figure 4c and compared to experimentally observed compositions obtained from TEM (dashed lines). The SiO\({}_{2}\) content is not predicted to change much with temperature, showing that the overall sensitivity to temperature for the components in the dispersed Si-rich phase is not significant. Generally, the disagreement between the computed and analytically measured compositions might indicate that the L\({}_{\text{Si}}\)-dispersed amoeboids are not necessarily formed under equilibrium conditions. However, the effects of alkali metals are also not considered in this work, which could have demonstrable consequences on the two-phase liquid stability. If instead of performing the calculation with compositions measured by TEM from Table 1, we consider the slightly more iron- (and calcium-) deficient data measured by SEM (refer to the left green-dashed line in Figure 2b), a small range of stability for the two-phase liquid is predicted between 1404-1415 for L\({}_{\text{Si}}\)-dispersed amoeboid morphologies. This is calculated near the iron-rich phase boundary, which extends just beyond the SEM composition (61 wt% FeO) to 61.6 wt% FeO at 1404 \({}^{\circ}\)C.