Online Applications

  • This material is partially based upon work supported by the National Science Foundation under Grant EAR-1225733, 1926734; part of broader impact activities.

MAP of Users

Google Analytics recorded more than 2300 users with unique IP addresses and ~4000 modeling sessions using these tools and databases in the 12 months prior to June 17, 2022.


  • A software package used to calculate thermodynamic properties for minerals, gases, aqueous species, and reactions at high temperatures and pressures.
  • For this version of sᴜᴘᴄʀᴛ (sᴜᴘᴄʀᴛʙʟ), we used a more recent mineral database of Holland and Powell (2011) and modified the computer code to accommodate the different heat capacity function, volume as a function of temperature and pressure, and mineral phase transition using the Landau model (Holland and Powell, 1998).
  • We also added more species to the database. For example, we included arsenic minerals and aqueous species, aluminum species from Tagirov and Schott (2001), aqueous silica from Rimstidt (1997), and dawsonite from Benezeth et al. (2007). Please cite Zimmer et al. (2016) sᴜᴘᴄʀᴛʙʟ in your publications if you have used sᴜᴘᴄʀᴛʙʟ in your research. The stated temperature and pressure ranges for aqueous species are from 1 to 5000 bars and 0° to 1000°C, but the ranges exceed the original limits stated for minerals in Johnson et al. (1992), and vary for individual species.


  • ᴘʜʀᴇᴇǫᴄ is a geochemical modeling software distributed by the U.S. Geological Survey and developed by David Parkhurst and Tony Appelo. It is written in the C and C++ programming languages and is designed to perform a wide variety of aqueous geochemical modeling calculations.
  • Here, the online version frees users from downloading and installing on different computing platforms. Additionally, the code has been modified by David Parkhurst to be able to calculate at elevated temperatures and pressures. New thermodynamic and kinetics datasets have thermodynamic properties that are consistent with those in Zimmer et al. (2016) and a library of BASIC language RATES blocks for about 100 minerals in Zhang et al. (2019).

CO₂ Calculator

  • An online program to facilitate the calculation of CO₂ solubility in pure water and aqueous 0-4.5 mNaCl solutions from 273 to 533K and from 0 to 2000 bar using the model by Duan, Sun, Zhu, Chou (2006).


  • An interactive program, developed to link sᴜᴘᴄʀᴛʙʟ and ᴘʜʀᴇᴇǫᴄ to facilitate modeling at temperatures and pressures suitable for clastic and carbonate diagenesis, geological carbon storage, and geothermal applications.
  • Supᴘʜʀᴇᴇǫᴄ converts the log K values of aqueous, mineral, and gas species reactions from the output of sᴜᴘᴄʀᴛʙʟ at user-specified temperatures and pressures and their associated molar volume parameters into the format of the ᴘʜʀᴇᴇǫᴄ database.
  • Users can generate a database bl-dat at temperature up to 1000 °C and pressure up to 5000 bars.

Rates Calculator

  • Calculates far-from-equilibrium dissolution rates at a temperature and pH of your interest.


  • A library of RATES blocks for about 100 minerals in BASIC scripts. The scripts can also be used as templates for writing other rate equations users might wish to use.
  • Both RATES and PHASES blocks are included in data file phreeqc-kinetics.dat, llnl-kinetics.dat, diagenesis.dat, and geothermal.dat which are options for online ᴘʜʀᴇᴇǫᴄ. If you just need to know the value of reaction rates at a temperature and pH of interest, you can use the rate calculator below. All phases in the library are included in the calculator.

H2S Calculator

  • An online program to calculate H2S solubility.