Dear MSA-listers, Please consider registering for the PyGeoChemCalc workshop occurring on the Saturday before this summer's Goldschmidt conference in Montreal. You'll have the chance to learn about this powerful software package in the morning and have the afternoon/evening free to enjoy the wonderful city of Montreal! Hope to see you there, Ben Tutolo and Dapo Awolayo PyGeochemCalc: A Python package for geochemical thermodynamic calculations from ambient to deep Earth conditions Saturday, 11 July 2026 09:00 - 12:00 PyGeochemCalc (pyGCC) is an open-source Python package that provides an integrated set of functions to calculate the thermodynamic properties of aqueous, mineral, and gas species and reactions amongst these species. It permits the estimation of the thermodynamic properties of mineral solid-solutions and variable-structure and variable-chemistry clay minerals and calculation of the thermodynamic properties of saline solutions as a function of temperature and pressure. The PyGCC package utilizes the well-established revised Helgeson-Kirkham-Flowers (HKF) equation of state, and density extrapolations based on it, with the IAPWS95 and DEW equation of state model for water properties, to calculate the thermodynamic properties of aqueous species at ambient to deep Earth temperature and pressure conditions. In this workshop, the developers of PyGCC will provide tutorials for using the package to perform thermodynamic calculations as well as generate thermodynamic databases for software including the Geochemist's Workbench, EQ3/6, PFLOTRAN, TOUGHREACT, and - new this year - PHREEQC. We will also provide examples of how Python tools can be used to efficiently and effectively run automated 'big data' simulations of water-rock interaction using these tools. Active course participants will be proficient users of the software by the time that the workshop concludes. Computer requirements: Participation in the short course will require that users install python (preferably the Anaconda package) on their own personal computers. Usage of software such as the Geochemist's Workbench or EQ3/6 will also require the installation of this software. Each participant will receive both a paper and electronic copy of the detailed handouts to be used during the lecture portions of the workshop. Intended audience: Late undergraduate, graduate students, and post-doctoral researchers, scientists, principal investigators, and faculties who are interested in the quantitative and qualitative description of water-rock interactions from ambient to deep Earth conditions. Associate Professor Department of Earth, Energy, and Environment University of Calgary 550 Earth Sciences, 2500 University Dr NW Calgary, AB T2N 1N4 Canada https://researchdirectory.ucalgary.ca/reactive-transport/<https://researchdirectory.ucalgary.ca/reactive-transport/research>