Mesoarchean silicic volcanics of the Kursk block, Voronezh crystalline massif: composition, age and correlation with the Ukrainian shield

Abstract

Rhyolites and basite rocks are present in the Archaean greenstone belts of the Kursk Domain (KD) of the East Sarmatia. The rhyolite age is 3122 ± 9 Ma (zircons, SIMS). A positive εNd (3122) = + 0.9 for rhyolites and their Sm-Nd model age ТNd (DM) = 3300 Ma as well as the age of the inherited zircon (3250 Ma) testifies to the participation of the more ancient crust component in the formation of rhyolite magmas. In geochemistry, rhyolites are very close to the TTG of the KD with an age 2.96-3.03 Ga. In the Middle Dnieper granite - greenstone area there are rhyolites and dacites with an age of 3.12 Ga with εNd (T) = + 0.6 - (+1.2) and very close geochemical characteristics. Thus, the hypothesis of a common geological history of the eastern part of Ukrainian Shield and KD in Mesoarchean is confirmed.