PTMAFIC - SOFTWARE PACKAGE FOR THERMOMETRY, BAROMETRY, AND ACTIVITY CALCULATIONS IN MAFIC ROCKS USING AN IBM-COMPATIBLE COMPUTER

PTMAFIC (v. 2.0) is a program for IBM-compatible personal computers wi th minimum hardware requirements, that can be used in thermometric and barometric calculations by petrologists concerned with the determinat ion of P-T paths in mafic and ultramafic rocks. The program creates AS CII files of normalized chemical analyses of amphiboles, garnet, epido te, ilmenite, muscovite, pyroxenes (ortho- and clinopyroxene), olivine , plagioclase, and spinel. The program carries out a wide range of sto ichiometric and thermodynamic calculations on these minerals, such as cation site-allocations at the different structural positions, the mol ar fractions and mole percent of the end-member terms, and the applica tion of different thermodynamic models for Calculation of activity coe fficients and activities. The program contains calibrations published for 13 geothermometers and 12 geobarometers applicable to mafic and ul tramafic rocks that cover metamorphic conditions, ranging from granuli te and eclogite facies to green-schist facies.