Impact Event and Subsequent Geologic Evolution

The Puchezh-Katunki crater is filled in with crater lake deposits (up to 400 m thick), which consist of coptomict gritstones and sandstones and predominant clays of Kovernino Formation. Crater deposits are entirely overlain by Middle Jurassic to Cretaceous marine sediments and Neogene to Quaternary continental deposits. The isotope (K–Ar, Ar–Ar) dating indicates an Early Jurassic (Sinemurian) age for the Puchezh-Katunki impact event but geological and paleogeographic data evidence rather Middle Jurassic (Bajocian) age; palynostratigrafic data are uncertain and contradictory. However, an Early Jurassic (Sinemurian of Early Pliensbachian; ca. 190–192 Ma) age for the Puchezh-Katunki impact structure is assumed to be more warranted.