Zircon growth and its modification during polyphase granulite-facies metamorphism – case study in the Moldanubian Zone of the southern Bohemian Massif

The proposed project is aimed at the deciphering of polyphase metamorphism and especially at the dating of particular metamorphic events in the course of the HP-HT evolution of granulite-facies rocks. Several zircon populations in granulites of the southern part of the Bohemian Massif are indicative of varied processes of its growth or modification. Since the zircon dating is the most often used tool for dating of the metamorphic rock and metamorphic processes, assigning discrete zircon populations to a specific metamorphic event appears to be crucial in modern metamorphic petrology and geochemistry. For a more robust and reliable interpretations of zircon ages we will try to introduce a new methods for distinguish individual zircon populations – besides conventional methods as are external habit, internal structure or chemistry of trace elements, we will use EBSD structural observations and Hf isotopic analyses in conjunction with precise in-situ laser ablation ICPMS U-Pb dating.