TCInvestigator: automated calculation of mineral mode and composition contours for <scp>thermocalc</scp> pseudosections

Abstract

Abstract Forward thermodynamic modelling is a commonly used tool for examining the thermobarometric history of a rock. Such models are being applied to a widening range of rock types using increasingly complex model systems. A useful aspect of phase equilibria modelling using pseudosections is the ability to calculate the modal abundance and compositions of phases, in addition to overall phase relations. However, calculating and plotting such data with thermocalc , a popular modelling program, is time consuming. In this article, we provide the methods and a description of a Matlab ® computer program, TCI nvestigator, which uses thermocalc 3.40 to automatically contour pre‐calculated pressure–temperature pseudosections with modal abundance and mineral composition parameters. The ability to calculate, plot and visualize these parameters automatically and rapidly, allows for a more in‐depth investigation into the metamorphic evolution of a rock. Data can be contoured for all minerals that are present in all fields on the pseudosection, rather than a selection of fields or phases that are a priori considered relevant. Examples of contoured pseudosections for pelitic and greywacke bulk compositions are presented, along with accompanying data sets, to illustrate the applications of this program. The software and example files are available from the CSIRO Data Access Portal at the following address: doi: 10.4225/08/54C99E2D47150 .