Simon has kindly written a new tutorial on calculating compatibility diagrams in THERMOCALC. This tutorial is the second of a three-part series that highlights the relationship between P-T projections, compatibility diagrams and pseudosections. If you’d like to try calculating some compatibility diagrams, or you’re interested in understanding more deeply how phase equilibrium calculations can be applied to rocks, I’d recommend this excellent short tutorial.
I’ve just issued an update to the igneous set of x-eos, involving tiny changes to the thermo of orthopyroxene. 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,
Dear friends, colleagues, and all HPx-eos/THERMOCALC users,
There will be a hiatus in news, as, in common with the rest of the global community, we work to handle the effects of the COVID-19 pandemic on our professional and personal lives. I hope to return to website developments in June, after the end of semester.
Wishing all of you the very best at this difficult time,
Eleanor and the rest of the team
I’ve now finished the THERMOCALC section of the website, other than some exceptions listed below. In the last few days I’ve rationalised and completed the documentation for P-T projection and pseudosection calculations. I’ll be moving on to add more about the HPx-eos, which will be relevant to users of THERMOCALC, Perple_X and other software.
Outstanding THERMOCALC-related material:
- THERMOCALC 3.50 is still in beta, and currently we don’t trust it to handle several of the less common calculation facilities. I will write more about those when the working software is released.
- Simon is still working on his excellent set of tutorials, as well as an app for plotting compatibility diagrams (with some kind help from John!).
Have fun, please report any broken links or glaring omissions.
Corinne Frigo has been visiting Melbourne from ANU. Corinne is working with Hugh O’Neill, Richard Arculus and Eleanor on ARC Discovery Project DP170100982, A new perspective on melting in the Earth and the origin of basalts. She has some very interesting experimental results on peridotite melting in CMAS + Cr2O3 + K2O at 30 kbar, which contrast nicely with the experiments of Liu & O’Neill (2004) at 11 kbar.
The experiments are giving the x-eos a workout! Currently, the model pyroxenes are taking too much Al2O3 in high-Cr2O3 bulk compositions, meaning that we should revise the Al-Cr partitioning here. Experiments in small systems are extremely useful, providing constraints that can’t be extracted from the natural system data available. Eleanor and Corinne will continue to look at this problem over the next few months, and their new insights will ultimately be incorporated into the next generation of igneous x-eos.
Do you want to use the HPx-eos in Perple_X? Are you struggling to work out which combination of dataset files, solution models and make/exclusion statements to use? Jeff Moyen has constructed a handy spreadsheet and is kindly sharing it with the community.
Please note, neither Jeff nor I are guaranteeing this information, and correct use of Perple_X is still the user’s responsibility. Do read the notes in the solution_model.dat file!
DRAWPD 1.18 can now be downloaded, including a working Windows version. Did you know that DRAWPD lets you plot coloured and ornamented lines? (as of version 1.16 I believe). An example of this is bundled with the download.
We continue to work on comprehensive .csv output for all THERMOCALC calculation modes, to facilitate more flexible plotting.
Update 8-2-2020: There is now drawpd documentation available at the link above, along with a slightly updated version of DRAWPD 1.18 (small changes to what appears on screen, nothing likely to affect the user).
Many thanks to those users who confirmed that the previous version was now working! Please continue to report any problems.
Luca Ziberna and I are planning to hold a workshop in Trieste, Italy, in the first week of September 2020 (the week before the European Mineralogy Conference in Krakow, 6-10 September).
The workshop will focus on the HPx-eos and their use, with THERMOCALC as our main modelling tool.
At this stage we’d like to hear from the community which might attract more interest:
- a workshop with substantial time spent on getting started with THERMOCALC
- a more wide-ranging exploration of potential applications for the HPx-eos and phase equilibrium modelling in general – i.e. with more interest for those who don’t want to use THERMOCALC itself, or are already expert users.
If you’d potentially be interested in coming to this workshop, please let us know what sort of content you’d be interested in! You can do this via the poll on the workshop webpage, through the discussion group, or by contacting us directly.