The Campanian-Maastrichtian benthic foraminiferal assemblages at the Elles section (Tunisia): A perspective for paleoenvironmental, paleobathymetric and sea-level fluctuation reconstruction

The Late Cretaceous Period experienced prevailing hothouse conditions that were characterized by relatively elevated atmospheric p CO 2 concentrations, high global mean sea level and mostly lacking ice sheets. These conditions were interrupted by an overall global decreasing trend in temperature during the CampanianMaastrichtian interval (83.65 to 66.04 Ma). The Upper Cretaceous sedimentary successions in Tunisia (southwestern Tethyan Ocean) like at the Elles section are regarded as unique archives for investigating paleoenvironmental and paleoclimatic changes, as well as constrain oscillations of sea-level. Here, we perform high resolution quantitative analysis of the benthic foraminiferal assemblages in the Campanian-Maastrichtian interval at the Elles section in order to infer palaeoenvironmental and paleobathymetric changes in relative sea- level. The Campanian succession (Abiod Fm.) is inferred to be deposited at upper to middle bathyal (i.e., 540-675 m) and is characterized by prevailing well-oxygenated conditions and low organic matter flux to the seafloor. The Campanian/Maastrichtian transition-coincides with the lowermost part of the El Haria Fm. deposited in outer neritic to upper bathyal settings under oligotrophic, well-oxygenated and reduced productivity conditions. Shallower depositional setting (i.e., 436-515 m) is inferred for the Maastrichtian succession (El Haria Fm.) that is also characterized by a lowering in oxygen availability at the seafloor associated with an increase of organic matter. Eight main sea-level regressions (four in the Campanian, one at the CampanianMaastrichtian transition and three in the Maastrichtian) have been identified and biostratigraphically constrained. These sea-level regression events are mostly accompanied by a negative excursion carbon isotope (delta 13C) 13 C) and their stratigraphical positions appear to be quite consistent with those previously recognized at the nearby El Kef section.