Sokerin Mikhail Yurievich RussiaSyktyvkar Institute of Geology of Komi Science Centre of the Ural Branch of Russian Academy of Sciences, 54 Pervomaiskaya St., Syktyvkar 167982, Russiasokerin@geo.komisc.ru Author's articles Paleogene quartz sandstones of the Sosnovka Formation of the Uljanovsk-Syzran Volga region (Eastern Russian Platform): Mineral composition and origin