Metamorphic Phase Equilibria

THERIAK-DOMINO files, Holland & Powell (1998) database

This site contains various database files for use in the Theriak-Domino software package (de Capitani & Brown, 1987; de Capitani & Petrakakis, 2010). Please check back occasionally for error fixes. Please report any errors you find to me so the files can be updated.

Holland & Powell (1998) ds5.5 files

Nobody has reported errors in tcds55_p07.txt for several years so it should be fairly reliable. This file contains the Holland & Powell (1998) database, update 5.5, and several a-x models for use in program THERMOCALC. My comparisons to THERMOCALC constructed diagrams in NCKFMASHTO show nearly identical results to THERMOCALC constructed diagrams with the exception of some chlorite-bearing equilibria at low temperature (due to the equipartition problem). References for the included a-x models are listed in the file.

THERIAK-DOMINO files, Holland & Powell (2011) database

Four groups of a-x files for dataset 6 have been converted and tested for use with the 2017 version of Theriak-Domino. They will all be made available soon. If you are having difficulty with these files when calculating in ferric-free bulk system compositions, please read the Ferric iron problems section below.

MnNCKFMASHTO metapelites (White et al., 2014)

This file is a translation of ax file tc-6axmn.txt and database file tc-ds62.txt found in the distribution for metapelites in the MnNCKFMASHTO system found at this site:

Download file: Please read the comments in the file before using.

High-P/mantle models (Holland et al., 2013)

  • available soon

Mantle melt models (Jennings & Holland, 2015)

  • available soon

Metabasites with melting (Green et al., 2016)

  • available soon

Tips for working with files

Ferric iron problems

The ds6 version of files above handle ferric iron differently than the ds5.5 file. The ds5.5 file handles ferric iron by explicitly using ferric iron (F3) as a system component that is different from ferrous iron (FE). The ds6 files use the traditional approach used in Theriak-Domino by controlling the amount of ferric iron in a calculation by specifying the proper amount of oxygen, and there is thus only one Fe system component, denoted FE. A problem sometimes arises when using a file set up in this manner in a ferric-free system, where Theriak-Domino cannot calculate an equilibrium correctly becauses it tries to make a finite amount of a ferric-bearing phase in some solid solution phases. You can detect this by running Theriak and carefully looking at the output. There are two solutions to this problem when calculating in ferric-free system compositions with the ds6 files. 1) Comment/deactivate all ferric-bearing members of solution models, which can become tedious and error prone. 2) Add a tiny amount of extra oxygen to the calculation allowing a minute amount of ferric-bearing members to be stable. The latter is easily accomplished by adding two Oxygen entries last in the bulk composition entry in THERIN (or therin.txt). The first is O(?) and the second is a very small value (O.0001). You can experiment with the latter value. An example composition:


Theriak-Domino 11.02.2015 executables for Windows

These executables were compiled on a Windows 7 machine with an i7 processer (2012) with gfortran. -O3, static builds. They were compiled using slightly modified version of the 11.02.2015 Theriak-Domino source code base, not the most recent 04.02.2017 source code available from the Theriak-Domino website. These executables and the included database were used to calculate the diagram below.

Download executables.

Figure 7 from White, Powell & Johnson (2014 JMG; WPJ14) was used to compare the results of calculations between programs Domino and THERMOCALC. The diagram below shows assemblage boundaries calculated by Domino as dashed black lines and those from WPJ14 as solid red lines. The results indicate the Theriak-Domino programs can reproduce THERMOCALC results very well using the executables and database files from the download above. The chemical system is MnNCKFMASHTO and the calculations used thermodynamic data from the THERMOCALC dataset 6.2.

Fig. 7 Comparison image


de Capitani, C., and Brown, T.H., 1987. The computation of chemical equilibrium in complex systems containing non-ideal solutions: Geochim. Cosmochim. Acta, v. 51, p. 2639-2652.

de Capitani, C., and Petrakakis, K., 2010. The computation of equilibrium assemblage diagrams with Theriak/Domino software: American Mineralogist, v. 95, p. 1006-1016.

Holland, T.J.B., and Powell, R., 1998. An internally consistent thermodynamic data set for phases of petrological interest: Journal of Metamorphic Geology, v. 16, no. 3, p. 309-343.

Holland, T.J.B., and Powell, R., 2011. An improved and extended internally consistent thermodynamic dataset for phases of petrological interest, involving a new equation of state for solids: Journal of Metamorphic Geology, v. 29, no. 3, p. 333-383.

White, R.W., Powell, R., and Johnson, T.E., 2014. The effect of Mn on mineral stability in metapelites revisited; new a-x relations for manganese-bearing minerals: Journal of Metamorphic Geology, v. 32, no. 8, p. 809-828.