The notion of “distinguishability” between bulk elastic parameters on the basis of the Gibbs deformation energy

The present work aims in discussing a principle that distinguishes between elastic parameters sets, on the basis of an energetic criterion: once a reference set, is given, another one can be fixed, so that they are as close as possible to each other, but yield non-equivalent deformation energy curves, i.e. they give, and, such that, calculated using the equation of state (EoS), and its uncertainty σ[ΔGdeform], obtained by a propagation of the errors affecting {Φ} are crucial to fix which mineral assemblage forms at P-T conditions and allow one to assess the reliability of such a prediction. We explore some properties related to the principle introduced, using the average values of the elastic parameters found in literature and related uncertainties for di-octahedral mica, olivine, garnet and clinopyroxene. Two elementary applications are briefly discussed: the effect of refining V0 in fitting EoSs to P-V experimental data, in the case of garnet and omphacite, and the phengite 3T-2M1 relative stability, controlled by pressure.