On parameterizing thermodynamic descriptions of minerals for petrological calculations

Abstract

A new regularization approach, termed micro-φ{symbol}, is outlined for parameterizing activity-composition (a-x) relations and other aspects of the thermodynamic descriptions of minerals for petrological calculations. In the context of the symmetric formalism, a formulation of a-x relations that is easily generalizable to multi-component minerals, parameterization with micro-φ{symbol} extends from where there are good data available to constrain, for example, interaction energies, to where there are little or no data. This involves decomposing the interaction energies, which are macroscopic between end-members, into their microscopic components involving interactions between elements on site..