Ciekawe stanowisko mikrofauny młodszego paleogenu w wierceniu Machowinko koło Słupska

Ewa Odrzywolska-Bieńkowa



An interesting rich microfaunal assemblage of the Late Paleogene age was recently found in the borehole Machowinko, Słupsk area (NW Poland). The Upper Eocene, developed in clay facies from the depth of 154 m to 145 m, is characterized by a rich assemblage of foraminifers common in coeval deposits from the western Europe as well as in the Kiev stage (Upper Eocene) of the USSR. The most important species of that assemblage include: Lenticulina dimorpha (Tutk.), Cylindroclavulina cylindrica (Hantk.), Brizalina antegressa (Subb.), Brizalina reticulataformis (Chal.), Bulimina aksuatica Moroz. and Heterolepa perlucida (Nutt.). The Ruppelian desposits, developed in similar facies as underlaying Upper Eocene deposits, occur from 145 m to 128 m depth. The guide species found in these deposits include: Turrillina alsatica (Andreae), Rotaliatina bulimoides (Reuss), Alabamina tangentialis (Clod.), Pyrulina cylindroides (Reuss) and Trifarina gracilis teniustriata (Reuss). The benthic species predominate among foraminifer species recorded from both the Upper Eocene and Ruppelian. Among planktonic species recorded from the Upper Eocene deposits most important are Globonomalina micra (Cole) and Acarinina rugosoaculeata Subb. Innumerous planktonic foraminifers found in the Ruppelian will be treated elsewhere. Up to the present it was possible to identify the species Globigerina gortanii (Borsetti). The foraminifer species found in the core material are sufficient for reliable correlation of the Late Paleogene deposits with coeval deposits of the western Europe and the USSR. The species Turrillina alsatica (Andreae) is very common which makes possible to assume that the deposits yielding it corresponds to the “Rupel 2” of D. Spiegler (1965) which according to that author, dates the maximum of the Oligocene transgression in the North Europe. The profile studied ends with siltstones with glauconite. Organic remains are here represented by sponge spicules and plant remains are plant remains only, similarly as in the case of higher parts of the Oligocene in the eastern Europe. The paper ends with some paleoecological and paleobathymetric conclusion drawn from the analysis of specific composition of formaninifer assemblages.

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