# Advanced Modeling Programs

## MELTS

Karl Wirth and Rachel Teasdale MELTS is a software package designed to model phase (mineral, rock and liquid) relations during melting and crystallization. MELTS can be used to model processes such as partial melting, equilibrium crystallization, fractional crystallization, and assimilation. Users can compute equilibrium phase relations for igneous systems over the temperature range 500-2000 °C and the pressure range 0-2 GPa (0-~65 km; 20 kb).

## TWQ

Cam DavidsonTWQ is an easy to use Windows based program that allows you to calculate the position of phase equilibria in P-T, T-XCO

_{2}, and P-XCO_{2}space. You can also use it to calculate various activity diagrams.## Perplex

Dave HirschPerplex is a command-line-driven software package that performs Gibbs energy minimization to create phase diagrams and pseudosections. It has the ability to use a wide range of thermodynamic databases, activity models, and fluid equations of state. Its chief asset is the very rapid ability to produce pseudosections: with experience, a full pseudosection can be completed in a few minutes. The chief limitations are that the calculation method may introduce small artifacts into the diagrams, and it cannot at this time incorporate the ''equipartition constraint'' of some THERMOCALC activity models, producing minor inconsistencies between the results.

Compare Perplex and THERMOCALC.## THERMOCALC

Julie Baldwin, Dexter Perkins and Dave MogkTHERMOCALC is thermodynamic calculation software for tackling mineral equilibria problems. It has two main components: the application itself, and the internally-consistent thermodynamic dataset it uses. The mineral equilibria problems that can be addressed with THERMOCALC include

Compare Perplex and THERMOCALC.*inverse modeling*ones (geothermometry/barometry using average*PT*), and*forward modeling*ones (calculating phase diagrams for model systems).## Theriak-Domino

Dexter PerkinsTheriak-Domino is a suite of programs that can be used for calculating equilibrium phase diagrams (pseudosections: phase diagrams that include only those reactions experienced by a particular bulk composition) and for a number of other kinds of calculations. It is an easy to use package of programs that comes with several different internally consistent thermodynamic data sets.