Timing of ductile shearing within the Dr??k??iai-Polotsk Deformation Zone, Lithuania: a U-Pb titanite age

摘要

>A U-Pb dating of titanite from an augen granitoid mylonite in the Dr??k??iai-Polotsk Deformation Zone has yielded a concordant age of 1534 >?± >9 Ma. This light brown titanite follows the foliation in the host rock and was obviously formed during retrogression from amphibolite to epidote-amphibolite facies and coeval mylonitization. Shear zones of the same age are known in southern and central Sweden and in NE Poland. These E-W trending deformation zones accommodate both mafic and granitoid intrusions and are probably related to an extensional period in the Mesoproterozoic evolution in the western part of the East European Craton prior to the 1.50-1.45 Ga Danopolonian orogeny.