Introduction to Pʜʀᴇᴇǫᴄ
This work was partly supported by NSF grant EAR-1926734, the endowment for the Haydn Murray Chair, and the Office of the Vice Provost for Research of Indiana University.
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 (up to the T-P limits in the accompanying thermodynamic datasets, e.g., 1000 °C and 5000 bars).
In the pulldown menu, you can find the thermodynamic datasets distributed with ᴘʜʀᴇᴇǫᴄ by the USGS. We have added the library of BASIC language RATES blocks for about 100 minerals from Zhang et al. (2019) into these two datasets:
We added log K values for related phases in the PHASES block. All else in phreeqc.dat and llnl.dat were not changed.
The following thermodynamic datasets in the pulldown menu are consistent with thermodynamic properties in Zimmer et al. (2016) and updates documented in the SUPCRTBL log.
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. More specifically:
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, these datasets below use the thermodynamic properties of SiO2°(aq) from Miron et al. (2016):
Users can generate databases at P-T ranges of your interest using the program SupPʜʀᴇᴇǫᴄ.
Note that we do not advocate any dataset over others. Here we provide a utility to facilitate teaching and research.
Appelo, C.A.J., Parkhurst, D.L., Post, V.E.A., 2014. Equations for calculating hydrogeochemical reactions of minerals and gases such as CO2 at high pressures and temperatures. Geochimica et Cosmochimica Acta 125, 49-67.
Parkhurst, D.L., Appelo, C., 2013. Description of input and examples for ᴘʜʀᴇᴇǫᴄ version 3--A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. Techniques and Methods 6-A43, U.S. Geological Survey, Reston, VA., 497.
Miron, G.D., Wagner, T., Kulik, D.A. and Heinrich, C.A. (2016) Internally consistent thermodynamic data for aqueous species in the system Na–K–Al–Si–O–H–Cl. Geochim. Cosmochim. Acta 187, 41-78.
Zimmer, K., Zhang, Y.L., Lu, P., Chen, Y.Y., Zhang, G.R., Dalkilic, M. and Zhu, C. (2016) SUPCRTBL: A revised and extended thermodynamic dataset and software package of SUPCRT92. Computer and Geosciences 90:97-111. DOI
Zhang YL, Hu B, Teng YG, Zhu C (2019) A library of BASIC scripts of rate equations for geochemical modeling using ᴘʜʀᴇᴇǫᴄ. Computers & Geosciences, v133. DOI
Zhang GR, Lu P, Zhang YL, Tu K, *Zhu C (2020) SupPHREEQC: A program to generate customized ᴘʜʀᴇᴇǫᴄ thermodynamic database based on Supcrtbl. Computer and Geosciences v143. DOI
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