Nikashin Konstantin I. RussiaKazanKazan Federal University, 4/5, Kremlevskaya St., Kazan, 420008, Russiakostya97@inbox.ru Author's articles Volcanogenic material in upper jurassic-lower cretaceous deposits of the Eastern Russian plate and its sources Paleogene quartz sandstones of the Sosnovka Formation of the Uljanovsk-Syzran Volga region (Eastern Russian Platform): Mineral composition and origin