Increase of the oxygen vacancy component in bridgmanite with temperature


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The oxygen vacancy (OV, MgAlO2.5) contents in bridgmanite with periclase and/or a calcium ferrite-type MgAl2O4-Mg2SiO4 phase (CF-phase) were investigated at temperatures of 1700, 2000, and 2400 K and a pressure of 27 GPa using an ultrahigh-pressure multi-anvil press. The OV content increases significantly with increasing temperature. These variations are achieved by consuming periclase and the charge-coupled (CC, AlAlO3) component in bridgmanite when coexisting with periclase but not CF-phase (Fig. 1a), and by consuming periclase and CF-phase when coexisting with both periclase and CF-phase (Fig. 1b).

 

The content of OV and CC component (upper) and Al pfu (per formula units) (bottom) with temperature for (a) single-phase bridgmanite (open symbols) and that coexisting with periclase (solid symbols) and (b) bridgmanite coexisting with periclase and CF-phase. Abbreviations: Brg, bridgmanite; CF: calcium ferrite-type structure of MgAl2O4; Per, periclase; OV: MgAlO2.5; CC: AlAlO3.


Liu, Z., Akaogi, M., Katsura, T., 2019. Increase of the oxygen vacancy component in bridgmanite with temperature. Earth Planet. Sci. Lett. 505, 141-151.

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