High resolution planktic foraminiferal biostratigraphy and correlation across the Palaeocene/Eocene boundary in the Tethys

A comparative study of various sections from western Tethys allows us to de fine a new refined planktic foraminiferal biozonation valid for low and mid dle latitudes. The classical zones have been recognized along the Palaeocen e-Eocene transition, but high resolution methodology allows us to define ne w subzones, especially within the Palaeocene-Eocene boundary interval. The planktic foraminiferal faunal turnover across the PIE boundary is gradual w ith the exception of an acarininid diversification and their excursion towa rd higher latitudes. Acarinina berggreni is the first acarininid to evolve during the P/E event, whereas the first appearance of other acarininid spec ies (Acarinina sibaiyaensis, Acarinina africana and Acarinina quetra) occur red at or just above a dissolution clay layer present in most of the deep s ea sections. The extinction of the bathyal and abyssal small benthic forami nifera occurred just below the dissolution clay interval in the A. berggren i Subzone and constitutes an apparently isochronous datum. The isotopic and planktic foraminiferal excursions began at the base of the Acarinina bergg reni Subzone and ended at the top of the Acarinina sibaiyaensis Subzone.