RADIOMETRIC DATING OF GRANITIC-ROCKS FROM THE CENTRAL BOHEMIAN PLUTONIC COMPLEX (CZECH-REPUBLIC) - CONSTRAINTS ON THE CHRONOLOGY OF THERMALAND TECTONIC EVENTS ALONG THE MOLDANUBIAN-BARRANDIAN BOUNDARY

Single-zircon dating by step-wise evaporation has established that suc cessive granitic intrusions were emplaced in the Central Bohemian Plut onic Complex (CBPC) during a short time span of about 10 Ma. In agreem ent with field data, the Pozary trondhjemite, emplaced early at 351 +/ - 11 Ma and subcontemporaneously with the Sazava granodiorite dated at 349 +/- 12 Ma, was followed by the Blatna granodiorite at 346 +/- 10 Ma. The magnesium-potassium-rich units (durbachites) indicate younger ages both for the Certovo Bremeno melagranite at 343 +/- 6 Ma (within the CPBC) and for durbachite from the Trebic Massif (south-east of the CPBC) at 340 +/- 8 Ma. These data provide evidence that the sequence of intrusion and the age of the emplacement of the CBPC are comparable with those of other western Variscan batholiths (i.e the Vosges or th e French Massif Central) in similar structural environment.