Late Callovian and Early Oxfordian ostracods from the Dubki section (Saratov area, Russia): implications for stratigraphy, paleoecology, eustatic cycles and palaeobiogeography

摘要

Thirty species of ostracods from Upper Callovian to Lower Oxfordian deposits in the Dubki section (Saratov region) have been studied, characterizing the lower part of the upper to lower sublitoral. A curve reflecting eustatic cycles and the connected benthic temperature has been constructed. The regressive development of the basin had reciprocating character, with an antiestuarine type of water circulation. When the Saratov Volga region, the Samarskaya luka and Central Russia are compared the ostracods indicate a greater depth in the eastern part of the basin as well as weaker cold benthic currents in the Late Callovian and stronger warm superficial currents in the Early Oxfordian.