Biostratigraphy and palaeoenvironments of the Eocene deep-water deposits of the Tarcau Nappe (Eastern Carpathians, Romania) based on agglutinated foraminifera and calcareous nannofossil assemblages

The micropalaeontological and sedimentological study of two representative sections from the Tarcau Nappe (Brusturosu stream, External Flysch of the Eastern Carpathians, Romania) provides new biostratigraphical and palaeoenvironmental data on the Eocene deposits. In both sections the foraminiferal assemblages are dominated by agglutinated taxa (Bathysiphon sp., Nothia spp., Ammodiscus spp., Paratrochamminoides spp., Reophax spp., Reticulophragmium spp. etc.); the calcareous benthic taxa are rare, represented by Laevidentalina and Stilostomella. Except for the M3b morphogroup (flattened irregular forms), all agglutinated foraminifera morphogroups were identified in the studied samples. The assemblages are composed of deep-water agglutinated foraminifera species which belong to the "Flysch-Type Biofacies" characteristic of a bathyal palaeoenvironment. Based on the presence of the calcareous nannofossils Chiasmolithus grandis, Isthmolithus recurvus, Chiasmolithus oamaruensis and Reticulofenestra reticulata as well as the foraminiferal species Psamminopelta gradsteini, Reticulophragmium amplectens and Saccamminoides carpathicus, the age of the deposits is assigned to the Bartonian (the BR-1 section) and the Priabonian (the BR-2 section).