The stratigraphic scale of the Eastern Paratethys is revised based on a study of the Neogene stratotype and reference sections, their biotic characteristics, and paleomagnetic and sedimentological data. New data on the correlation of its regional subdivisions with the Central Paratethys and Mediterranean stratotypes are presented. The section “Regional Stage Scale of the Eastern Paratethys” considers the history of identification and a brief description of the horizons of the regional scale, which later became regional stages, as well as their historical stratotypes and lectostratotypes, and division into Beds and Substages. The section “History of Separate Biota Groups” provides reviews on the most important groups of fauna, phytoplankton, and terrestrial vegetation, as well as on magnetostratigraphy, the possibility of correlation and dating of sections based on these data, and comparison with the Central Paratethys and stratotypes of the Mediterranean. In conclusion, the main results of the revision of the stratigraphic scheme of the Neogene of the Eastern Paratethys are given.

Разрез майкопских отложений р. Белая выше г. Майкопа является характерным для Западного и Центрального Предкавказья, хорошо обнаженным и изученным и может рассматриваться в качестве типового для майкопской серии. В нем наблюдается непрерывный переход от подстилающих светлых мергелей белоглинской свиты к темным глинам в основании майкопской серии. В нижнеолигоценовой части серии почти непрерывно обнажена пшехская свита, прослеживаются несогласия в подошве и кровле полбинского пласта. Выше следуют нижняя бескарбонатная и верхняя известковистая подсвиты свиты Морозкиной балки, баталпашинская и нерасчлененная септариевая+зеленчукская свиты верхнего олигоцена. Приводится подробное литологическое описание разреза с основными данными по ископаемым группам, описан состав изученного микрофитопланктона и фауны: наннопланктона, планктонных и бентосных фораминифер, моллюсков, ихтиофауны, приведены результаты палеомагнитного изучения разреза. Исследование палинологии и диноцист из этой же серии образцов было проведено ранее. Приведена история изучения майкопской серии и ее свитное деление, обсуждаются возможности использования полученных данных для ее корреляции и восстановления условий осадконакопления.

The Eocene interval of the section in the Belaya River valley is continuously exposed and is represented (from the bottom up) by green clays of the Cherkessk Formation, the marl–clayey member of the Keresta Formation, bituminous marls of the Kuma Formation, and light intensely bioturbated marls of the Belaya Glina Formation. There are gradual transitions between formations without signs of hiatuses. Eocene deposits are characterized by rich assemblages of nannoplankton, planktonic and benthic foraminifers (PF, BF), and organic-walled phytoplankton. The shallower water facies are recorded in the composition of benthos and mollusks at the boundaries of formations. The data on these groups of fossils make it possible to trace an almost complete zonal characterization of nannoplankton, dinocysts and PF and to compare these subdivisions of the middle–upper Eocene and early Oligocene both with other reference sections of the Eastern Peri-Tethys and standard zones and stages of the international stratigraphic scale. The following zones are distinguished: the upper part of the Cherkessk Formation—nannoplankton (NP15) and Acarinina bullbrooki PF zones; the Keresta Formation—nannoplankton (NP15+NP16) and Hantkenina “alabamensis” PF zones; the Kuma Formation—the nannoplankton (NP16+NP17) zones, Hantkenina “alabamensis” (at the lower boundary of the formation) and Subbotina turсmenica PF zones (above basal part), and Areosphaeridium diktyoplokum–Rhombodinium porosum dinocyst zone; the Belaya Glina Formation—nannoplankton (NP18, NP19+NP20, NP21) zones, Turborotalia centralis–Globigerinatheka tropicalis PF zone, and Charlesdowniea clathrata angulosa dinocyst zone; the lower part of the Pshekha Formation—nannoplankton (NP21) zone, Globigerina officinalis PF zone, and Phtanoperidinium amoenum dinocyst zone. These data make it possible to clearly correlate the Belaya River section with the sections studied in detail in Ciscaucasia (Kheu, Kuban, and Gubs rivers) and to reconstruct the conditions of sedimentation.

The section of Maikop deposits on the Belaya River upstream of the town of Maikop is characteristic of Western and Central Ciscaucasia; it is well exposed and well-studied and can be considered as the type section of the Maikop Group. The section shows a continuous transition from the underlying white marl of the Belaya Glina Formation to dark clay lying at the base of the Maikop Group. The lower Oligocene part of the section exposes an almost uninterrupted outcrop of the Pshekha Formation and shows unconformities at the base and top of the Polbian Bed. These are overlain by the lower non-carbonate and upper carbonate subformations of the Morozkina Balka Formation and the Batalpashinsk and undivided Upper Oligocene Septarian + Zelenchuk formations. This paper contains a detailed lithological description of the section with a summary of its fossils. The composition of the studied microphytoplankton and animal remains, including nannoplankton, planktonic and benthic foraminifers, mollusks, and ichthyofauna is described and paleomagnetic study results are presented. The study of palynology and dinocysts from the same series of samples was previously completed. The history of the study of the Maikop Group and its subdivision into formations are discussed. This paper discusses the possibility of using the data for correlation and reconstruction of the depositional environment.

The Taman sections, reference for the Neogene of the Eastern Paratethys, are investigated thoroughly paleontologically and stratigraphically, with level-by-level description of four sections, correlated in detail with each other; fossil remains coming from them are examined conjointly, with uniform binding to the sections. The composition of malacofaunas and foraminifers allowed the recognition of all regional stages and substages from the Upper Chokrakian to Middle Kimmerian, their boundaries, and correlation with the Kerch stratotypes. The study of the taxonomic composition of ostracods improved the boundaries of stratigraphic ranges of particular species. The complete and continuous sequence of Karaganian–Konkian deposits has provided the data improving the volume and boundaries of the Konkian Regional Stage and showing that it is divided into three units. Investigation of these groups provided the stratigraphical basis for pioneer studies of phytoplankton; the taxonomic composition and distribution in the sections of nannoplankton, diatoms, and organic-walled phytoplankton are investigated completely for the first time; the points of penetra- tion of marine water into the basin are recognized. The most reliable tool for correlation of deposits in a semiclosed basin is distribution of “ecologically plastic” groups that are able to tolerate a wide range of salinity and variation of the gas regime, such as mollusks, benthic foraminifers, and, among phytoplankton, diatoms and dinocysts. The appearance of stratigraphically significant diatom and nannoplankton species in Konkian, Sarmatian, and Maeotian deposits allowed the comparison of intervals of their presence with the oceanic zones where these index species are provided with absolute dating. The level-by-level palynological characteristics of the beds is reported, providing the basis for reconstruction of climatic changes in this region.

Sea-level fluctuations in the terminal Eocene, Oligocene, and Neogene of the Eastern Paratethys are quantitatively assessed on the basis of facies and old coastlines traced on the northern platform shelf, levels of river valley incisions, and the study of seismic profiles. The first data massif allows the characterization and correlation of transgression stages in the history of the Eastern Paratethys. The greatest transgressions fall within the first half of the Late Eocene, mid-Early Oligocene, initial Late Oligocene, initial Early Miocene, the initial Tchokrakian, Karaganian and Sarmatian in the Middle Miocene, the middle and late Sarmatian and early Pontian in the Late Miocene, and the Akchagylian in the Caspian basin of the Pliocene. In contrast, the greatest incisions of northern rivers running from the platform allow us to establish the time and extent of the main declines in the base levels of the erosion. Maximal incisions date back to the terminal Eocene-initial Oligocene, terminal Solenovian time in the terminal Rupelian, the terminal Maikop in the Early Miocene, the terminal Sarmatian and middle Pontian in the Late Miocene, and the Early Pliocene in the Caspian basin. Large regressions also formed unconformity surfaces, traced on seismic profiles as erosion boundaries of several orders. The surfaces are confined to the Eocene/Oligocene boundary, middle and late Maikop, Sarmatian/Meotian boundary, middle Pontian, and terminal Miocene-initial Pliocene, as well as being traced even in the most deep-water basins. The synthesis of these data suggests a preliminary version for the curve of transgression-regression cyclicity. Its correlation with the eustatic curve shows their similarity only in the lower part-prior to the initial Middle Miocene, when Paratethys became a semi-closed basin.