Rheology of Earth Materials :

Closing the gap between timescales in the laboratory and in the mantle

14 August 2019 - First publication: when olivine transforms into anhydrous phase B

Anhydrous phase B (Anh‐B) is a dense magnesium silicate with composition (Mg, Fe)14Si5O24, which is expected to form in Mg‐rich or Si‐depleted regions of the mantle. We show that due to strong crystallographic similarities with the crystal structure of olivine, it can form directly from it as a metastable phase. We show that Anh‐B exhibits a moderate seismic anisotropy, which makes its detection difficult in the mantle.

This publication is published in open access in Geochemistry, Geophysics, Geosystems

A. Addad, P. Carrez, P. Cordier, D. Jacob, S-I Karato, A. Mohiuddin A. Mussi, B.C. Nzogang, P. Roussel & A. Tommasi (2019) Evidence for a new phase with six-coordinated silicon stable in conditions of the transition zone: structural characterization and elastic properties. Geochemistry, Geophysics, Geosystems, https://doi.org/10.1029/2019GC008429