New igneous x-eos: No more stable high-Ca opx

I’ve just issued an update to the igneous set of x-eos, involving tiny changes to the thermo of orthopyroxene (provided by Tim Holland). This should prevent high-Ca orthopyroxene from being stable, as has been seen in some calculations on peridotite. I’ll let Jamie Connolly know, so hopefully this change will shortly be implemented in Perple_X too.


As Melbourne goes back into lockdown, we reach the end of a bruising semester. Many apologies to those who have asked me questions recently and got no answer. Please ask again if your problem is still outstanding, as I have lost track of who you are.

Much appreciation to those of you who are, or soon will be, training the next generation of practical petrologists over the internet – and also to those budding petrologists who are being trained!

I hope all of you and your folks are safe and well,


Welcome Simon Schorn!

We’re delighted to welcome Simon to Melbourne, where he began his stay with a trip to Prahran market (left). Simon will be learning about xeos development with Eleanor, aiming to calibrate a single clinopyroxene HPx-eos to replace the three that are currently used in different geological contexts. He will also help to manage this website.

Simon recently gained his PhD, working with Johann Diener at the University of Cape Town, with a thesis entitled High-temperature metamorphism in the western Namaqua-Natal Metamorphic Province (South Africa): implications for low-pressure granulite terranes.

ENKI workshop

Eleanor is in Barcelona at the pre-Goldschmidt ENKI workshop, run by Mark Ghiorso and Aaron Wolf. ENKI is intended to provide an environment in which thermodynamic datasets and a-x relations can be developed and used in exceedingly flexible ways. So far it seems very promising – an admirable community software project! We will aim to implement the HPx-eos within ENKI.

Post-semester news from Melbourne

Now that the semester is over, Eleanor is writing a lot:

  • the website
  • the transparency paper: clarifying some aspects of the modelling that have been left unclear after recent developments
  • the “uncertainties” paper – really about sensitivity as much as uncertainty: looking at what we can say about uncertainties in the modelling, and contrasting it with what we’d like to say.

RP is away, so all is quiet!


Community information

To follow community news:

  • Join the discussion group.
  • Follow @hpxeos on Twitter.
  • Follow this WordPress blog by clicking the Follow button in the lower right hand corner of the page.

Upcoming events:

POSTPONED DUE TO COVID-19HPx-eos modelling workshopTrieste, Italy

Are you running a workshop on computational phase equilibrium modelling? Let us know and we can advertise it on this site.