In 2006 -2007, two boreholes (Odeska-6 and Odeska-20) were drilled on the south-western part
of the Ukrainian sec- tor of the Black Sea. According to the geophysical well- log data, borehole
Odeska-20 recovered sediments of the Paleocene (1151-1621 m) and Eocene (692-1151
m). We studied nannofossils from the Paleocene interval of both boreholes. The identified nannofossils
had a moderate to bad preservation. Four nannofossil zones of Martini (1971) and Okada & Bukry
(1980) were identified: com- bined Cruciplacolithus tenuis-Chiasmolithus danicus zone
(NP2-NP3/CP1b-CP2), Fasciculithus tympaniformis (NP5/CP4), Heliolithus kleinpellii
(NP6/CP5) and Heli- olithus riedelii (NP8/CP7). The combined C. tenuis-C. danicus zone
(NP2- NP3/CP1b-CP2) was distinguished only in borehole Odeska-6 (int. 1544-1635 m). The
most common species are: Coccolithus pelagicus, Neochiastozygus sp