Evaluations and a revision of the pyroxene geothermometry

This study evaluates the validity of several pyroxene geothermometers by comparing calculations with recent experimental studies that cover wide range of pressure and pyroxene composition. The most accurate thermometer for the multicomponent system among previously proposed models is that of Taylor (1998). This model yields temperatures ±32°C (1σ) for the multicomponent system, but provides temperatures lower than the experimental temperatures at low pressures in the CaO-MgO-SiO₂ (CMS) system. We propose a revised model of Wells (1977)’s pyroxene thermometer as, where the equilibrium constant K is the same as that of Wood and Banno (1973). This yields temperatures±35°C (1σ) for the multicomponent system and ±21°C for the CMS system.