Taukhe Fm

Pribrezhnoe Uplift

It mainly consists of silty mudstones, but its lithological composition is variable in different regions. The typical sections of the formation are represented by three rhythms each of them containing gravelstones or sandstones in the basal parts (Markevich et al., 2000). In some regions coarse-grained rocks dominate in the lower part of the formation. The total thickness of the Taukhe Formation is up to 1600m (Turbin, 1994).

Numerous fossils are reported from the formation. Among them, the most important for the determination of stratigraphic range are ammonites Thurmanniceras sp., Berriasella sp., Neocomites aff. retowskii, bivalves Myophorella nottica, Iotrigonia tauchiana, Buchia volgensis from the lower part and ammonites Thurmanniceras sp., Neocomites sp., Olcostephanus sp., Neohoploceras sp. and bivalves Buchia keyserlingi, B. inflata, B. pacifica and B. cf. uncitoides from the upper part (Turbin, 1994; Markevich et al., 2000). The ammonites from the lower part of the formation as well as B. volgensis are index fossils of the Berriasian. The upper part of the formation is considered as lower Valanginian based on the lower Valanginian assemblage of Buchia. Valanginian ammonite Neohoploceras sp. and Valanginian-Hauterivian ammonite Olcostephanus sp. do not contradict such stratigraphic range of this part of the formation. The presence of the lower Berriasian deposits in the Pribrezhnoe zone is debatable (Markevich et al., 2000). The remarkable feature of fossil assemblages from the Taukhe Formation is the mixed composition of fauna including Boreal Buchia and ammonites, trigoniids and some oysters (e.g., Rastellum) typical for the Tethyan Realm.