TY JOUR TI Manifestation of global events in the Upper Ordovician and Silurian sections of the Northern Urals region KW global biotic KW eustatic KW δ13C isotopic events KW Ordovician KW Silurian JO Proceedings of the Komi Science Centre of the Ural Division of the Russian Academy of Sciences AU Beznosova, T.M. AU Matveev, V.A. PY 2026 IS 0 PB FSBI FIC "Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences"