HPx-eos: metapelite set

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General information

Citation: White, RW, Powell, R, Holland, TJB, Johnson, TE & Green, ECR (2014). New mineral activity-composition relations for thermodynamic calculations in metapelitic systems. Journal of Metamorphic Geology 32 261-286.


PhaseAlso in setsFirst published
silicate meltthis paper
plagioclase and potassium feldsparmetabasite, igneousHolland et al (2021) J Metam Geol DOI 10.1111/jmg.12639
garnetmetabasitethis paper
biotitemetabasitethis paper
orthopyroxenemetabasitethis paper
muscovitemetabasite, igneousthis paper
margaritethis paper
cordieritethis paper
staurolitethis paper
chloritethis paper
chloritoidthis paper
epidotemetabasite, igneousHolland & Powell (2011) J Metamorph Geol 29 333-383
ilmenite and hematitemetabasiteWhite et al (2000) J Metamorph Geol 18 497-511
order-disorder magnetite White et al (2000) J Metamorph Geol 18 497-511
spinel magnetitemetabasiteWhite et al (2002) J Metamorph Geol 20 41-55
sapphirineWheller & Powell (2014) J Metamorph Geol 32 287-299

Use for: equilibria in typical metapelite bulk compositions at < 15 kbar (or cautiously at < 20 kbar).

Known issues:

  • Stability fields of white micas do not always seem plausible.
  • Calculations tend to predict garnet-biotite assemblages rather than garnet-biotite-kyanite assemblages, owing to excessively magnesian compositions of model phases.
  • Are you aware of any other problems? Please let us know!

Full model details and benchmark calculations

Here we provide human-readable details of the metapelite-set HPx-eos, along with benchmark calculations to allow implementations to be tested. Contact us if anything remains unclear.

Download full HPx-eos details for phases: garnet, silicate melt, plagioclase feldspar, K-feldspar, epidote, margarite, muscovite (also paragonite), biotite, orthopyroxene, sapphirine, cordierite, staurolite, chlorite, chloritoid, spinel (also magnetite), ilmenite (also hematite) (current 23-01-2022):

End-members from dataset version: 6.2 (Mon 6 Feb, 2012):

Benchmarks, generated with THERMOCALC 3.50 (thanks to Simon for help with these). These files don’t necessarily represent key (or necessarily most stable) equilibria; they are just to check implementation of the x-eos. Contact us if you need specific additional calculations for comparison and are unable to produce these yourself. Download here:

Download THERMOCALC input files

If you’re new to THERMOCALC, please begin by reading the THERMOCALC section of the website, and download the files below as directed in the Get started guide.

Download THERMOCALC input files/information for the metapelite-set HPx-eos here (the current bundle is dated 23-01-2022):

  • Dataset 6.2 input file tc-ds62.txt (Mon 6 Feb, 2012).
  • Axfiles formatted for THERMOCALC versions 3.47 and 3.50, in the systems KFMASH, NCKFMASHTO and MnNCKFMASHTO.
  • Full descriptions of the x-eos, including definitions of mixing sites, end-members and compositional variables.
  • Samecoding information and a selection of starting guesses for compositional/order variables that might be suitable as a starting point for a calculation.

Information related to use with other software

In Perple_X: HPx-eos that first appeared in the 2014 metapelite set are labelled “(W)”. Jeff Moyen’s spreadsheet gives more information.

Please contact us with other information that you think we should include here.