biostratigraphy

The Gubkino Horizon (Turonian-Coniacian) in the Bolshoy Kamenny ovrag section (Zhirnovsk town, Volgograd Region) has not been purposefully studied so far. As a result of biostratigraphic and magnetostratigraphic researches the carbonate rocks of the Gubkino Horizon were first divided into zones based on benthic foraminifera complexes and characterized by geomagnetic polarity and rock-magnetism data. The most part of the Bolshoy Kamenny ovrag section is covered by the reverse polarity zone.

A detailed description of the Upper Jurassic formations of the south of the European part of Russia, mainly restricted by the Kimmeridgian and Volgian stages, is given. The characteristic of the reference section is provided for the Vechkusy Formation, and the neostratotype is proposed for the Novikovka Formation. The criteria for drawing the boundaries of local stratigraphic units (formations) and the features of strata distribution are considered in detail.