Abstract:

Common ore-forming fluid systems can be approximated as a CO2-H2O-NaCl system or its subsystems. Once the ore-forming
fluids are trapped and sealed by minerals during the ore-forming process, fluid inclusions will form. Physicochemical parameters of the
ore-forming fluids, such as temperature, pressure and composition, can be obtained by the thermodynamic studies of fluid inclusions.
Although pH is an important physicochemical parameter, the pH study of fluid inclusions is still at the primary stage. Up to now, only a
few researchers measured the pH of CO2-H2O-NaCl system, and some researchers developed the thermodynamic models to calculate the
pH of this system. Combining with the previous work, we systematically summarize the pH calculation models of the important fluid
inclusion systems (H2O, NaCl-H2O and CO2-H2O-NaCl) and present an accurate calculation program for the relevant systems. in this
paper. The executable codes of the calculation programs for these systems can be obtained from this journal or the corresponding author.

Key words: fluid inclusion, pH, thermodynamic model, program calculation