BENTHIC FORAMINIFERAL ASSEMBLAGES BETWEEN 2 MAJOR EXTINCTION EVENTS -THE PALEOCENE EL KEF SECTION, TUNISIA

The development of benthic foraminiferal assemblages from the Paleocen e outcrops of the El Haria Formation near El Kef, Tunisia is discussed qualitatively and quantitatively. The aim of the study is to reconstr uct the paleoenvironmental evolution between the K/Pg boundary interva l and the late Paleocene event, and to compare this evolution with res ults from other sites along the southern Tethyan margin. Eighty-four s amples, covering virtually the entire Paleocene, provide a dataset tha t allows detailed qualitative and multivariate analysis. The benthic f oraminiferal faunas indicate a complex pattern of environmental change s during the Paleocene, marked by the succession of different benthic associations. Following the K/Pg boundary event, community restoration was characterized by the gradual build-up of faunal diversity. Decrea sing dominance and the entry of taxa common to normal marine, outer ne ritic to upper bathyal environments indicate the completion of the eco system restoration in Zone P1b. A highly diverse benthic foraminiferal assemblage persisted throughout the remainder of the early Paleocene into the earliest late Paleocene. At the P3a-P3b zonal transition rela tive sea-level lowering is evidenced by the sudden disappearance or de creasing abundance of deeper-water taxa (e.g. Anomalinoides affinis, A . susanaensis, Gavelinella beccariiformis). Neritic deposition continu ed into Zone P4, when trophic levels at the seafloor increased as indi cated by the entry and increasing dominance of species such as Anomali noides cf, aegyptiacus, Bulimina midwayensis, and B. strobila, which w e consider to be sensitive to eutrophication. The combined effect of s hallowing and the subsequent eutrophication led to the establishment o f assemblages similar to late Paleocene benthic foraminiferal assembla ges from Egyptian sections, some of which record the latest Paleocene extinction event, These assemblages were interpreted to be indicative of a middle neritic, highly eutrophic environment. Enhanced vertical f luxes of organic matter along the southern Tethyan margin may have res ulted from intensified upwelling. This eventually led to oxygen defici ency at the seafloor. It appears that oxygen-deficient, high-productiv ity shelves were a common feature of the southern Tethyan margin durin g the latest Paleocene.