Biostratigraphy of the Paleocene of the coastal part of East Stara Planina based on small benthic Foraminifera

Abstract

An attempt to elucidate the biostratigraphical importance of Paleocene benthic foraminifera of the coastal part of East Stara Planina is presented. Three zones and two subzones were defined. The zones are: Clavulunoides trilaterus Local Taxon Range Zone (Late Early Paleocene – Late Paleocene), Bathysiphon sp. – Oridorsalis megastomos Local Assemblage Zone (Early Paleocene) and Bathysiphon sp. – Saccammina placenta Local Assemblage Zone (Middle – Late Paleocene). The last zone was divided into two subzones: Bathysiphon microrhaphidus Abundance Subzone (Middle Paleocene) and Saccammina placenta Abundance Subzone (Late Paleocene). The zones were successfully correlated to the conventional planktic foraminiferal and calcareous nannoplankton ones, defined in the same area. The taxonomical composition and the structure of the zonal assemblages indicates different paleoecological parameters in the northern and the southern part of the studied area and shows the strong dependence of benthic foraminifera on paleoenvironment.