Water Concentration in Single‐Crystal (Al,Fe)‐Bearing Bridgmanite Grown From the Hydrous Melt: Implications for Dehydration Melting at the Topmost Lower Mantle

High‐quality single‐crystals of (Al,Fe)‐bearing bridgmanite, Mg 0.88 Fe 3+ 0.065 Fe 2+ 0.035 Al 0.14 Si 0.90 O 3 , of hundreds of micrometer size were synthesized at 24 GPa and 1800 °C in a Kawai‐type apparatus from the starting hydrous melt containing ~6.7 wt% water. Analyses of synthesized bridgmanite using petrographic microscopy, scanning electron microscopy, and transmission electron microscopy show that the crystals are chemically...