Event stratification of the sections constitutes an investigation trend aimed at detailed interregional correlation of sedimentary sequences. Based on extensive factual material, the authors have revealed the most significant changes in the Middle Triassic sedimentary and volcanogenic-sedimentary bodies. The entire Middle Triassic is peculiar for manifestations of hydrothermal-metasomatic processes within terrigenous, biogenic, volcanogenic bodies and bodies of mixed origins.