Wiek izotopowy a wiek paleomagnetyczny ryodacytów z Zalasu koło Krakowa (S Polska)

The single-grain U-Pb dating of most zircon grains separated from the Zalas rhyodacites gave mean age of the magma emplacement 294.2 š 2.1 Ma. Some zircons, however, displayed younger ages (268.7š 3.4 Ma), probably related to metasomatic alterations of these rocks. The paleomagnetic ages of the Zalas intrusion and its metasomatosis are slightly younger. It is probably connected with a certain error of time calibration of the reference apparent polar wander path used for paleomagnetic dating.