Th-U-Pb Age of Metamophism of the Vorontsovka Group Rocks, Voronezh Crystalline Massif, from Microbrobe Dating of Monazites

摘要

The Paleoproterozoic metaterrigenous rocks of the Vorontsovka Group were studied. This series occupies a large area between the Precambrian crustal segments of the East European Craton, Sarmatia, and Volgo-Uralia. Based on the data of Th-U-Pb microprobe dating of monazites from the Vorontsovka Group, the age of zonal metamorphism is 2039 + 26 Ma for the staurolite zone, 2015 ± 14 Ma for the muscovite- sillimanite zone, and 2008 ± 20 for the sillimanite-K-spar-cordierite zone. These data imply subsynchro-nity of the regional metamorphism and penetration of collision S-type granites of the Bobrov Complex about 2020 Ma B.P.