The mechanism of solution of aluminum oxide in MgSiO₃ perovskite

Jonathan F. Stebbins , Scott Kroeker , Denis Andrault (1)

1 IPGP - Institut de Physique du Globe de Paris

We report ²⁷Al and ²⁹Si Nuclear Magnetic Resonance (NMR) spectra, collected at magnetic fields of 14.1 and 18.8 Tesla on samples as small as 1 mg, for Al-bearing MgSiO₃ perovskite synthesized at 26-28 GPa. For Al, we find a 1∶1 ratio of two types of sites: a symmetrical, octahedral site and a low symmetry, distorted site that is most likely to be Al in modifications of normally eight-coordinated Mg sites. A charge coupled substitution of 2 Al for one Si and one Mg cation is strongly supported as the predominant mechanism in this pressure range.

Domaines: Planète et Univers [physics]

Jonathan F. Stebbins, Scott Kroeker, Denis Andrault. The mechanism of solution of aluminum oxide in MgSiO₃ perovskite. Geophysical Research Letters, 2001, 28, pp.615-618. ⟨10.1029/2000GL012279⟩. ⟨insu-03597766⟩