Oskar Thalhammer, Anna Vymazalova and Federica Zaccarini (contact: Federica.Zaccarini@unileoben.ac.at)

Accessory minerals occur in small quantities in their host rocks, usually representing less than the 5% of the modal composition. For this reason they are not considered an essential component. Nevertheless, a number of them can be used to obtain precise geo-chronological data, to model the physical-chemical condition of their crystallization and they can also provide information about the type of magma and/or fluid from which they and their host rocks formed. Mafic-ultramafic rocks contains a series of accessory phases, including the platinum group minerals (PGM), that are able to accurately constrain the origin and the age of the metallogenic system and those of their host rocks. This session aims to stimulate the discussion about the important role of the accessory minerals in different rocks by combining contributions from the full range of modern mineralogical and geochemical investigation techniques. This session is dedicated to Prof. Giorgio Garuti and to his first 50 years of academic activity.