Abstract
Isothermal experiments under hydrothermal conditions were carried out at four different temperatures as a function of time and H2O content (0.3-2.2wt%) for the purpose of examining the effect of H2O on kinetics of the Mg2GeO4 olivinespinel transformation. The results reveal that H2O can activate the transformation with increase of its content at least up to∼2wt%. The transformation process in the presence of H2O was discussed and a new model via an intermediate state was proposed, that is, atoms constituting the olivine may once dissolve into the supercritical fluid and then precipitate into the spinel structure.
