Phase Equilibria with THERIAK-DOMINO¶
Alternate builds of the Theriak-Domino software package written by Christian de Capitani (de Capitani & Brown, 1987; de Capitani & Petrakakis, 2010) are provided below. The downloads provided here were compiled using slightly modified source code that the Theriak-Domino website makes available to developers. In addition to the compiled binaries, various translations of the Holland & Powell (1998, 2011) thermodynamic datasets and a-x models available from the HPx-eos and older Mainz THERMOCALC websites are also included. These thermodynamic dataset and a-x files are known to work with the binaries provided in the downloads below; they should also work with the 2020 package release from the official Theriak-Domino website but I have not tested them with that package.
Program, database & example files¶
Database files only¶
td-ds62-mp50-03.txt: Holland & Powell (2011) ds6.2 & translation of HPx-eos metapelite ax file tc-mp50MnNCKFMASHTO.txt
Holland & Powell (2011) ds6.2 metabasite file as used in Jørgensen et al. (2019) coming soon
Files for use with versions of Theriak-Domino released before 2020 are available upon request.
Ferric iron problems¶
The ds6 version of files downloadable above handle ferric iron differently than the older ds5.5 files I that appearred here in the past. The ds5.5 files handled 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 or by specifying multiple system components with varable valence states (e.g. Fe & S with sulfur-bearing phases present), 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 struggles to 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 small amount of extra oxygen to the system composition to allow a minor 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 small value (O.01). You can experiment with the latter value. An example composition:
I am slowly working on recording a set of tutorials on program installation and use. Check back soon.
Comparison of Calculated Diagrams¶
Below is a comparison of a pseudosection calculated with both program THERMOCALC and program Domino in 2018. The comparison uses the Beard & Lofgren (1991) metabasite melting experiment composition as reported in Green et al. (2016; JMG). The thermodynamic database used was Holland & Powell (2011) ds6.2. The a-x models are those used in Green et al. (2016), as obtained from the THERMOCALC website in file tc-6axNCKFMASHTOm45.txt in the metabasite_mac.zip distribution in approximately 2016. The models were converted to Theriak-Domino format and the diagram recalculated using program Domino (dashed lines) and program THERMOCALC (version tc345i). Program Domino was based on the 11.02.2015 distribution of source code from the Theriak-Domino website.
This figure can be compared to Fig. 4a of Green et al. (2016). This calculation used a dqf on the gl member of the clinoamphibole model of -3 kJ/mol, whereas Fig. 4a of Green et al. (2016) used 0 kJ/mol.
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.
Green, E.C.R., White, R.W., Diener, J.F.A., Powell, R., Holland, T.J.B. and Palin, R.M., 2016. Activity-composition relations for the calculation of partial melting equilibria in metabasic rocks. Journal of Metamorphic Geology.
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.
Jørgensen, T. R. C., Tinkham, D. K. and Lesher, C. M., 2019. Low-P and high-T metamorphism of basalts: Insights from the Sudbury impact melt sheet aureole and thermodynamic modelling. Journal of Metamorphic Geology, v. 37, no. 2, p. 271-313.
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.