A Metamorphic History from Electron Microprobe Dating of Monazite: Variscan Evolution of The Tatra Mountains

The recent development of the chemical Th-U-Pb method for in situ dating of monazite using an electron microprobe (EMP) has made it possible to determine multiple thermal events during orogenesis (e.g. Montel et al., 1996, Cocherie et al., 1998, Wil-liams et al., 1999). The aim of this study is to constrain a meta-morphic history using EMP dating of monazite on example of the Tatra Mts. We compare our results with those obtained from single-grain, cathodoluminescence-controlled, U-Pb dating of zircons (Poller et al., 2000, Poller and Todt, 2000). Analytical procedure and age determination Analyses of monazites were carried out using the Cameca SX-100 microprobe. Acceleration voltage of 15 kV was used rather then 25 kV, because of less strong ZAF correction factors. The beam diameter varied from 2 to 6 µm according to the possibili-ties to analyse only single phase in the monazite. Larger beam