TWQ or TWEEQU (Thermobarometry With Estimation of Equilibration State) is an interactive program for calculation of mineral-fluid equilibria. It has been developed & maintained by Rob Berman of the Geological Survey of Canada. Although it can calculate many types of phase diagrams, its primary application is geothermobarometry using internally consistent thermodynamic data for endmembers and solid solutions that have been derived simultaneously from relevant experimental constraints.

At present, there is no Apple Macintosh version of this software.

A new Windows version, winTWQ, supercedes earlier DOS versions (1 and 2) described below.

winTWQ (version 2.32)

If you want to become a registered TWQ user and receive update/revision information, please register using the online form. If you have questions or comments, please contact Rob Berman.

Released as Geological Survey of Canada Open File 5462 and available as a free download from GeoPub.

winTWQ includes updated documentation and these main programs:

The version 2.32 thermodynamic database incorporates K-Na-CASH endmembers from Berman (1988, J Pet), along with endmember & solution properties derived from analysis of relevant experimental data described in the publications below:

• Fe-Mg garnet, olivine, cordierite, ilmenite, & Fe-Mg-Al orthopyroxene, (Berman & Aranovich, 1995, CMP 119:30-42)
• Mn-Fe-Mg mixing properties of garnet, and endmember properties of spessartine based on the experimental data of Feenstra and Peters (1996, CMP, 126, 109-120) and Feenstra and Engi (1998, CMP, 131, 379-392), along with natural datasets of Williams & Grambling (1990, AMin, 75, 886-908)
• revised properties for biotite endmembers (phl, annite, siderophyllite, eastonite) and Fe-Mg-Al-Ti mixing, based on:
  1. Al solubility data for Fe-Al, Mg-Al, Fe-Mg-Al biotite (Berman et al. 2007; Am Mineral, v.92, in press)
  2. ol-bi Fe-Mg exchange data for Fe-Mg-Ti biotite (Zhou, 1994)
  3. analysis of gt-bi and gt-bi-plg-qz/GASP applications to natural assemblages

Further description is given in the winTWQ documentation and in these publications:

• Reversed phase equilibrium constraints on the stability of Mg-Fe-Al biotite (v. 92, p139-150)
• Optimized standard state and solution properties of minerals: I. model calibration for olivine, orthopyroxene, cordierite, garnet, and ilmenite in the system FeO-MgO-CaO-Al₂O₃-TiO₂-SiO₂
• Reassessment of the garnet-clinopyroxene, Fe-Mg exchange thermometer: II. thermodynamic analysis

Thermobarometry With Estimation of Equilibration State [TWEEQU]: a Software Package For IBM or Compatible Personal Computers:

TWQ (version 1.02, June, 1992)

Thermodynamic data of Berman (1988), Berman (1990) with amphibole thermobarometry capabilities from Mader et al. (1994)

Released as Geological Survey of Canada Open File 2534 and available as a free download from GeoPub.

TWQ (versions 2.01 and 2.02)

Released as Geological Survey of Canada Open File 5408 and available as a free download from GeoPub.

• TWQ2.01 (version 2.01, October, 1996)

  Thermodynamic data of Berman (1988) updated with internally consistent solid solution and end-member data for garnet, olivine, orthopyroxene, cordierite, ilmenite from (Berman & Aranovich, 1996)

  Described in these publications :

  • Optimized standard state and solution properties of minerals: I. model calibration for olivine, orthopyroxene, cordierite, garnet, and ilmenite in the system FeO-MgO-CaO-Al₂O₃-TiO₂-SiO₂
  • Optimized standard state and solution properties of minerals, II. comparisons, predictions, and applications
  • A new garnet-orthopyroxene thermometer based on reversed Al2O3 solubility in FeO-Al₂O₃-SiO₂ orthopyroxene
    
    
• TWQ2.02 (version 2.02, January, 1997)

  Thermodynamic data of Berman (1988) updated with internally consistent solid solution and end-member data for:

  • garnet, olivine, orthopyroxene, cordierite, ilmenite from (Berman & Aranovich, 1996)
  • clinopyroxene (Berman et al., 1995)
  • biotite, spinel (Berman & Aranovich, unpublished data)

  Described in the above publications and in the following:

  • Reassessment of the garnet-clinopyroxene, Fe-Mg exchange thermometer: II. thermodynamic analysis

Other files that are included with the above downloads include:

• GTCPX.ZIP - program for calculating gt-cpx temperatures (CMP, 119, 30-42)
• B88.MIN - TWQ format thermodynamic data of Berman (1998; J Pet, 29, 445-522)
• Ge0TAB.EXE - program for making tables of thermodynamic data