An unconstrained formulation for thermodynamic complex solution phase minimization

Abstract

While the last decade has seen significant progress in thermo-mechanical modelling of complex multiphase systems, the coupling with petrological thermodynamic modelling approaches, when addressed at all, remains a difficult task. First, most phase equilibria modeling tools have been developed with the primary focus to produce phase diagrams (e.g., Perple_X, Theriak_Domino, geoPS, MELTS) and do not offer useful interfaces for (parallel) geodynamic codes. Second, phase equilibrium modelling is generally achieved by solving a Gibbs energy minimization problem. This problem is computationally challenging as it involves solving a nested optimization problem subject to both equality and inequality..