Monazite Th-U-total Pb ages of "bostonite" and granite in the Mecsek and Velence Hills

The age determination method based on microprobe measurements of the Th, U and Pb contents of monazite, and used since the nineties, was applied to Hungarian igneous rocks: the so-called "bostonite" and the granitoids of the Velence Hills and Mecsek Mountains. Measurement results were evaluated by two different methods that produced similar ages; for the sake of precaution the obtained values were mostly accepted by the greater uncertainty domain calculated by linear regression. The age of 117±13 Ma for the "bostonite" proves that this rock is a member of the Lower Cretaceous igneous series. The age of 210±18 Ma obtained for the Nadap granite in the Velence Hills agrees with published data while that of 255±17 Ma obtained for the Kismoragy microgranite in the Mecsek Mountains is younger than previously known.