Biostratigraphic remarks on the Caltavuturo Formation (Eocene-Oligocene) cropping out at Portella Colla (Madonie Mts., Sicily)

An outcrop of the Caltavuturo Formation (Eocene-Oligocene) in the Madonie Mts. (Northern Sicily) has been micropaleontologically investigated. Two stratigraphic sections were sampled and studied in rock thin sections. The formation consists of marly clays and several 2-30 cm thick breccia layers, rich in larger foraminifers, and is affected by prominent silicification and bioturbation. The clayey layers are dominated by deep-water agglutinated foraminifera (DWAF) in isolated forms, with rare epibathyal and bathyal hyaline taxa, which disappears at the top of the succession. The collected samples are barren of planktonic foraminifera and calcareous nannoplankton. Selected larger benthic foraminifers species in the displaced layer register a vertical variation and were analysed to have a biostratigraphical control according to shallow benthic zones (SBZ). Heterostegina reticulata italiaca, Borelis vonderschmitti, Halkyardia minima, Dyscocyclina dispansa dispansa, Orbitoclypeus varians and Nummulites ex. gr. incrassatus mark the upper Eocene assemblages. Nummulites vascus dominates the Early Rupelian assemblages in association with N. fichteli, Halkyardia maxima, Operculina complanata and Heterostegina sp., whereas the FO of Nephrolepidina praemarginata marks the Late Rupelian. Imbrication of resedimented larger foraminiferal tests indicates a N-S paleodirection of the flows.