Hf Isotopic Composition of Zircons from the Granodiorites of the Talovsky Intrusion as the Evidence for the Juvenile Paleoproterozoic Crust of the Vorontsovsky Terrane, Eastern Sarmatia

Abstract

The Vorontsovsky terrane occupies the Eastern part of the Volga-Don orogen, which is located between the Archean Kursk block (Sarmatia megablock) and the Volgo-Uralia megablock (Eastern European platform). Along with geochemical and geochronological studies, the studies of the Hf isotopic composition of accessory zircons present great interest and can give important information about the melt sources of the numerous granitoid intrusions and the age of the continental crust of the Vorontsovsky terrane. Zircons from the granodiorites of the Talovsky massif, located in the Eastern part of the Vorontsovsky terrane, which intrudes into the Paleoproterozoic metaterrigenic sequences of the Vorontsovsky series, were studied using the Neptune Plus multi-collector mass spectrometer with NWR 213 laser ablation system. Obtained positive values of ε_Hf(2050) ranging from +2.1 to +5.4 point out to a very brief crustal prehistory of the source of their parental melts. This fact excludes the presence of the Archaean crust in the Vorontsovsky terrane. Thus, Hf isotopic composition of zircons from the granodiorites of the Talovsky intrusion is another independent evidence for the juvenile Paleoproterozoic crust of the Vorontsovsky terrane separating the megablocks of Sarmatia and Volgo-Uralia.