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Introduction to ᴘʜʀᴇᴇǫᴄ

  • Online Version of ᴘʜʀᴇᴇǫᴄ
  • Version 3 Documentation by Parkhurst and Appelo (2013)
  • Example Input Files
  • USGS Software User Rights Notice

  • ᴘʜʀᴇᴇǫᴄ is a geochemical modeling software distributed by the U.S. Geological Survey and developed by David Parkhurst and Tony Appelo. The version here, modified by David Parkhurst, is capable of calculations at elevated temperatures and pressures. High P-T calculations need to use proper thermodynamic datasets, which is described below.


    You can find the thermodynamic datasets distributed with the ᴘʜʀᴇᴇǫᴄ software in the menu. We added the library of BASIC language RATES blocks for about 100 minerals from Zhang et al. (2019) to these two datasets.

  • phreeqc-kinetics.dat, originally phreeqc.dat (e.g., log K, Appelo et al., 2014, hyperlink) up to 200 oC and 1 kb for a small set of species. We added the library of BASIC language RATES blocks for about 100 minerals and log K values for related PHASES. See more info on the tab ᴘʜʀᴇᴇǫᴄ BASIC RATE SCRIPTS.
  • llnl-kinetics.dat, originally llnl.dat (e.g., log K). We added the library of BASIC language RATES blocks for about 100 minerals and log K values for related PHASES. See more info on the tab ᴘʜʀᴇᴇǫᴄ BASIC RATE SCRIPTS.

  • Additionally, we have included new datasets. These new datasets have thermodynamic properties consistent with those in Zimmer et al. (2016) and allow ᴘʜʀᴇᴇǫᴄ calculations at elevated temperature and pressure.

  • diagenesis.dat follows the framework of phreeqc.dat and covers the T-P range of 0.01-100 °C at 1 bar and 100-200 °C at PSAT. It has the Appelo et al. (2014) pressure correction to 1000 bars and Peng-Robinson equation for calculating the gas fugacity. The Davies equation for aqueous species activity coefficients is used.
  • geothermal.dat takes the framework of llnl.dat and covers the T-P range of 0.01-100 °C at 1 bar and 100-300 °C at PSAT. It uses the B-dot equation parameters for activity coefficients of aqueous species. Additionally, a library of BASIC language RATES blocks for about 50 minerals and log K values for related PHASES. See more info on the tab ᴘʜʀᴇᴇǫᴄ BASIC RATE SCRIPTS.
  • bl-0.5kb.dat: 65 – 350 °C, 0.5kb
  • bl-1kb.dat: 110 – 600 °C, 1kb
  • bl-2kb.dat: 180 – 940 °C, 2kb
  • bl-5kb.dat: 300 – 1000 °C, 5kb

  • You can generate databases at other P-T ranges using the program SupPʜʀᴇᴇǫᴄ..

    Disclaimer

    This material was prepared, in part, sponsored by an agency of the United States Government or Indiana University. Neither the United States Government, nor Indiana University, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.

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