Thermobar: An open-source Python3 tool for thermobarometry and hygrometry

Penny E. Wieser, Maurizio Petrelli, Jordan Lubbers, Eric Wieser, Sinan Özaydın, Adam J.R. Kent, Christy B. Till

Research output: Contribution to journalArticlepeer-review


We present Thermobar, a new open-source Python3 package for calculating pressures, temperatures, and melt compositions from mineral and mineral-melt equilibria. Thermobar allows users to perform calculations with >100 popular parameterizations involving liquid, olivine-liquid, olivine-spinel, pyroxene only, pyroxene-liquid, two pyroxene, feldspar-liquid, two feldspar, amphibole only, amphibole-liquid, amphibole-plagioclase and garnet equilibria. Thermobar is the first open-source tool which can match up all possible pairs of phases from a given region, and apply various equilibrium tests to identify pairs from which to calculate pressures and temperatures (e.g. pyroxene-liquid, two pyroxene, feldspar-liquid, two feldspar, amphibole-liquid). Thermobar also contains functions allowing users to propagate analytical errors using Monte Carlo methods, convert pressures to depths using different crustal density profiles, plot mineral classification and mineral-melt equilibrium diagrams, calculate liquid viscosities, and convert between oxygen fugacity values, buffer positions and Fe speciation in a silicate melt. Thermobar can be downloaded using pip, and extensive documentation is available at

Original languageEnglish (US)
Pages (from-to)349-384
Number of pages36
Issue number2
StatePublished - 2022


  • Clinopyroxene
  • Hygrometry
  • Monte-carlo
  • Open-source
  • Plagioclase
  • Python
  • Thermobarometry

ASJC Scopus subject areas

  • Geophysics
  • Geology
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)


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