In Ukraine, the perspective oil and gas bearing regions are located within the Carpathian-Black Sea segment of the Tethys, and the southern slopes of the East European Platform. We examined the plankton microfossil content from numerous Paleogene samples obtained from outcrop and exploration borehole sections. The interpretation of the large dataset concerning the spatial-temporal distribution of Foraminifera, Calcareous nannofossils and Dinocysts is provided. The characteristics of the stratigraphic distribution of planktonic fossil assemblages in the Paleogene sections, their cyclicity in the formations and the specifics of the zonal subdivision based on the defined correlation levels are given. As a result of an integrated study the biozonal subdivision of Paleogene sediments of Ukraine is substantiated, and an interregional correlation of various facies of the Paleogene sections with the International Stratigraphic Scheme is undertaken.

Calcareous nannofossils from Paleocene sediments of two boreholes (Odeska-6 and 20) from the north-western shelf of the Black Sea are examined. Five nannofossil Zones are identified according to the standard zonations of Martini (1971) and Quillévéré et al. (2002): the Chiasmolithus danicus Zone (NP3), the upper part of Ellipsolithus Macellus Zone (NP4b), the Fasciculithus tympaniformis Zone (NP5), the Heliolithus kleinpelli Zone (NP6) and the Heliolithus riedelii Zone (NP8). This biostratigraphical work allows us to correlate the Bilokamian and Kachian regional stages of the Stratigraphic Scheme of Southern Ukraine (Zernetskiy et al., 1993) to the standard nannofossil zonations and, therefore, to the International Chronostratigraphic scheme. The presence of an unconformity between the Bilokamian and Kachian regional stages in the borehole section of Odeska-6 is suggested by Linear Sedimentary Rates estimated for the two boreholes. This unconformity corresponds to the upper part of the Chiasmolithus danicus nannofossil Zone (NP3) and the lower part of Ellipsolithus Macellus (NP4a), and is estimated to last nearly 1.94Ma.