Advances in thermodynamic modelling tools for metamorphic rocks

Retrieving the thermodynamic properties of metamorphic rocks such as mineral/melt/fluid fractions, compositions, densities and thermal properties is essential for studying, quantifying, and modelling the reactive thermo-mechanical evolution of the lithosphere. These properties are derived from experimental data and are used to calibrate thermodynamic models, which can then predict melt-rock phase equilibria using a so-called Gibbs free energy minimization.

Here, we present recent advancements in modelling thermodynamic equilibrium achieved with the open-source parallel software package MAGEMin. These include the addition of a new thermodynamic database for dry alkaline magmatic systems and the continued development of our new Julia-based graphical user interface (MAGEMinApp), which greatly simplifies the calculation of phase equilibria.

MAGEMinApp’s functionality include the calculation of Pressure-Temperature-Composition diagrams (P-T, P-X, T-X, PT-X), modelling of Pressure-Temperature-Composition paths (fractional melting/crystallization with assimilation/extraction), trace-element and zirconium saturation predictive modelling, specific heat capacity calculation accounting for latent heat of reaction, mineral and magma classification (e.g., TAS diagram), as well as a new sensitivity analysis tool to investigate the control of bulk-rock composition on phase assemblage stability.