Sedimentology and depositional system of a transitional shallow marine – coastal complex, Lower Visean deposits in the Central Volga-Ural Petroleum Province, Orenburg

Abstract The paper presents a study of Lower Carboniferous (Visean) clastic sequence commonly called Bobrikovsky Formation, deposited in the Volga-Ural Petroleum Province, Orenburg Region. Our investigation included sedimentological description core samples from hydrocarbon wells and well log correlations. Facies were identified by patterns calibrated sedimentology. Formation is proposed to be interpreted as an overall transgressive-regressive succession nearshore-tidal environment. Transgressive lagoon-estuary barrier island facies became regressional lagoon fill-type settings.