Review of the K/T boundary Elles section (Tunisia): Proposition of a new parastratotype

The review of the Cretaceous-Tertiary interval deposits of the Elles sectio n based on a closer sampling than done before allows to well characterise t he K/T boundary and to reconstitute the geological events underlining this boundary. Than, the discovery of a thin Ir rich layer, with Ni and Cr rich spinel testify to the cosmic event. This sudden event added to some longer term other events (e.g. climatic, eustatic) generated a mass extinction, at the K/T boundary, of specialists among the globotruncanids and heterohelic ids planktic Foraminifera species. This biological crisis is followed by a slow biotic turnover into the Danian which contains also ecological general ist species inherited from the Cretaceous lot. The underlining of the all C retaceous-Tertiary interval biozones (i.e. A. mayaroensis zone, G. conusa z one, PV. eugubina subzone, P. pseudobulloides subzone, T. trinidadensis sub zone and a T. uncinata zone) certifies that the Elles section is complete. This Elles section, compared to the El Fief section (considered up today as the K/T stratotype) exposes a better K/T interval outcrops. Besides, at th e Elles section the interval deposits of the all indicated zones and subzon es is slightly more expanded than elsewhere. All these characteristics prev ail the Elles section to be proposed as a new stratotype or at least a para stratotype for the K/T boundary. Editions scientifiques et medicales Elsevi er SAS.