PHASE EQUILIBRIUM MODELLING: APPROACHES AND PITFALLS

Table of Contents

Days 1 and 2

THERMODYNAMIC DATABASES AND PHASE EQUILIBRIUM MODELLING SOFTWARE PACKAGES

Day 1 Monday May 10, 2021: Presentation 1a

Overview of thermodynamic databases and a-X models
Pierre Lanari, University of Bern
Pierre will open the workshop by providing an overview of the thermodynamic datasets and a-X models that are currently in use, before assessing the pros and cons of the various fitting procedures used to produce these data. He will highlight the need to check these datasets against experimental data and will address the problems of uncertainty and reliability. Finally, he will outline what comes next in the development of thermodynamic datasets.

Overview of thermodynamic databases and a-X models

Pierre Lanari, University of Bern

Pierre will open the workshop by providing an overview of the thermodynamic datasets and a-X models that are currently in use, before assessing the pros and cons of the various fitting procedures used to produce these data. He will highlight the need to check these datasets against experimental data and will address the problems of uncertainty and reliability. Finally, he will outline what comes next in the development of thermodynamic datasets.

Day 1 Monday May 10, 2021: Presentation 1b

THERMOCALC and AvePT
Dave Waters, University of Oxford
Dave will discuss the phase equilibrium software package THERMOCALC, an algebraic non-linear equation solver developed by Roger Powell and co-workers. He will explain how thermodynamic databases and a-X models are integrated into the program and what combinations of these are available for use. He will then cover the different types of calculations THERMOCALC can conduct, as well as any add-on programs. To conclude, he will summarise the strengths and weaknesses of the software for different types of thermodynamic calculation.

THERMOCALC and AvePT

Dave Waters, University of Oxford

Dave will discuss the phase equilibrium software package THERMOCALC, an algebraic non-linear equation solver developed by Roger Powell and co-workers. He will explain how thermodynamic databases and a-X models are integrated into the program and what combinations of these are available for use. He will then cover the different types of calculations THERMOCALC can conduct, as well as any add-on programs. To conclude, he will summarise the strengths and weaknesses of the software for different types of thermodynamic calculation.

Day 2 Tuesday May 11, 2021: Presentation 2a

Perple_X
Mark Caddick, Virginia Tech
Mark will present the phase equilibrium software package Perple_X, a Gibbs free energy minimizer developed by Jamie Connolly. This talk will broadly cover the same topics as the THERMOCALC talk, focussing on the capabilities of Perple_X.

Day 2 Tuesday May 11, 2021: Presentation 2b

Theriak-Domino and summary/comparison of different software packages
Doug Tinkham, Laurentian University
Doug will overview the phase equilibrium software package Theriak-Domino, a Gibbs free energy minimizer developed by Christian De Capitani. Once again, this talk will broadly cover the same topics as the THERMOCALC and Perple_X sessions but focus on Theriak-Domino. Doug will additionally provide a summary and comparison of the different softwares, addressing the strengths and weaknesses of each, as well as in which circumstances it may be beneficial to use certain programs.

Theriak-Domino and summary/comparison of different software packages

Doug Tinkham, Laurentian University

Doug will overview the phase equilibrium software package Theriak-Domino, a Gibbs free energy minimizer developed by Christian De Capitani. Once again, this talk will broadly cover the same topics as the THERMOCALC and Perple_X sessions but focus on Theriak-Domino. Doug will additionally provide a summary and comparison of the different softwares, addressing the strengths and weaknesses of each, as well as in which circumstances it may be beneficial to use certain programs.

DAYS 3 and 4:

FACTORS INFLUENCING THE RELIABILITY OF PHASE EQUILIBRIUM MODELLING

Day 3 Wednesday May 12, 2021: Presentation 3a

Uncertainties and "best practices" in phase equilibrium modelling
Dave Waters, University of Oxford
Dave will kick off the second part of the workshop by discussing the philosophy of classical geothermobarometry vs. phase diagram-based pressure-temperature estimation. He will discuss the main sources of uncertainty associated with phase equilibrium modelling (datasets, a-X models, bulk compositions, chemical systems, and departures from equilibrium), with each being examined in more detail in subsequent sessions. His talk will conclude with some recommended “best practices” to achieve optimal results from phase equilibrium modelling.

Uncertainties and "best practices" in phase equilibrium modelling

Dave Waters, University of Oxford

Dave will kick off the second part of the workshop by discussing the philosophy of classical geothermobarometry vs. phase diagram-based pressure-temperature estimation. He will discuss the main sources of uncertainty associated with phase equilibrium modelling (datasets, a-X models, bulk compositions, chemical systems, and departures from equilibrium), with each being examined in more detail in subsequent sessions. His talk will conclude with some recommended “best practices” to achieve optimal results from phase equilibrium modelling.

Day 3 Wednesday May 12, 2021: Presentation 3b

Reactive (effective) bulk composition and Bingo-Antidote
Pierre Lanari, University of Bern
Pierre will discuss the concept of reactive (effective) bulk composition and show examples where it must be considered. He will explain the concept of iterative thermodynamic modelling and demonstrate its application using the Bingo-Antidote software. His talk will conclude by discussing the implications that different treatments of reactive bulk compositions have for thermobarometry and petrochronology.

Reactive (effective) bulk composition and Bingo-Antidote

Pierre Lanari, University of Bern

Pierre will discuss the concept of reactive (effective) bulk composition and show examples where it must be considered. He will explain the concept of iterative thermodynamic modelling and demonstrate its application using the Bingo-Antidote software. His talk will conclude by discussing the implications that different treatments of reactive bulk compositions have for thermobarometry and petrochronology.

Day 4 Thursday May 13, 2021: Presentation 4a

The influence of kinetics
Dave Pattison and Jacob Forshaw, University of Calgary
Dave and Jacob will discuss how the assumption that metamorphic recrystallization never departs significantly from equilibrium may not extend to all of a rock’s prograde history, owing to kinetic impediments to reaction (e.g., nucleation, dissolution/growth, transport). Examples of petrologically-significant departures from equilibrium from contact and regional metamorphic settings will be provided. The talk will conclude with a discussion of how consideration of kinetics improves petrological interpretation.

The influence of kinetics

Dave Pattison and Jacob Forshaw, University of Calgary

Dave and Jacob will discuss how the assumption that metamorphic recrystallization never departs significantly from equilibrium may not extend to all of a rock’s prograde history, owing to kinetic impediments to reaction (e.g., nucleation, dissolution/growth, transport). Examples of petrologically-significant departures from equilibrium from contact and regional metamorphic settings will be provided. The talk will conclude with a discussion of how consideration of kinetics improves petrological interpretation.

Day 4 Thursday May 13, 2021: Presentation 4b

Assessment of thermodynamic databases/a-X models against the natural record
Jacob Forshaw and Dave Pattison, University of Calgary
Jacob and Dave will discuss how well current thermodynamic predictions reproduce natural observations (mineral assemblages, mineral compositions). Several examples will be provided that draw on compilations of natural data from metapelitic and metabasic bulk compositions spanning a range of metamorphic grade. The talk will conclude with a discussion of how the natural rock record can best be incorporated in the development of future thermodynamic models.

Assessment of thermodynamic databases/a-X models against the natural record

Jacob Forshaw and Dave Pattison, University of Calgary

Jacob and Dave will discuss how well current thermodynamic predictions reproduce natural observations (mineral assemblages, mineral compositions). Several examples will be provided that draw on compilations of natural data from metapelitic and metabasic bulk compositions spanning a range of metamorphic grade. The talk will conclude with a discussion of how the natural rock record can best be incorporated in the development of future thermodynamic models.

DAYS 5 Friday May 14, 2021

OPEN DISCUSSION OF TOPICS OF PETROLOGICAL INTEREST

Topics to be discussed will be based on responses to questions that are part of the registration process.