Olivine‐Ahrensite Phase Relations in the Mg$_2$SiO$_4$‐Fe$_2$SiO$_4$ System as a Function of Temperature

Olivine and ahrensite are the primary components of the interiors of Fe-rich terrestrial planets and meteorites, making their phase relations crucial for planetary science. Moreover, their phase relations can be used for calibrating large-volume high-pressure devices such as multi-anvil apparatus. Here we defined the olivine–ahrensite phase relations in the MgO-FeO-SiO$_2$ system at 7.5–12.0 GPa at 1,530 and 1,950 K using a multi-anvil apparatus. Combining the current results with our previously determined binary loop at 1,740 K, we re-estimated the shock parameters of several L5 and L6-types meteorites. Also, we determined the olivine-ahrensite phase ratio and compositions along cold and warm Mars aerotherms for Mg/(Mg + Fe) ratios of 0.75 and 0.80. Using this mineralogical model, we estimated and compared seismic wave velocity profiles in Mars' interior to data from the InSight geophysical mission.