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Integrated analysis of quantitative distribution patterns of organic-walled dinoflagellate cysts (dinocysts) and benthic foraminifera from the Paleocene El Kef section (NW Tunisia) allows the reconstruction of sea-level and productivity fluctuations. Our records indicate that the environment evolved from an initially oligotrophic, open marine, outer neritic to upper bathyal setting towards a more eutrophic inner neritic setting, influenced by coastal upwelling by the end of the Paleocene. An overall second order change in paleodepth is reflected by both microfossil groups. From the base of planktic foraminifera Zone P4 onwards, the main phase of shallowing is evidenced by an increase of inner neritic dinocysts of the Areoligera group, disappearance of deeper-water benthic foraminifera and increasing dominance of shallow-marine taxa (several buliminids, Haplophragmoides spp., Trochammina spp.). The total magnitude of this shallowing is obscured by interaction with a signal of eutrophication, but estimated to be around 150 m (from~200 to~50 m). Superimposed on the overall trend, third order sea-level fluctuations have been identified and correlated to sequences in other regions. Paleoproductivity indicators (notably protoperidinioid dinocysts and buliminids) show a trend from an oligotrophic to a eutrophic setting.

In the present study, we document paleoenvironmental change across the Danian-Selandian transition (planktic foraminiferal interval P2-P3b; calcareous nannofossil Zone NP4, Subzones NTp6-NTp8A; 61-59 Ma) in NW Tunisia. Diversifications of Paleogene planktic foraminifera with the evolution of the muricate and photosymbiotic lineages Morozovella, Acarinina and Igorina and of the biostratigraphically important nannofossils genus Fasciculithus are recorded within this interval. The present study aims to understand early Paleogene environmental changes in the southern Tethys, by analyzing the evolution of surfacewater and-to a lesser extent-seafloor conditions. Three localities were investigated: Ain Settara, Elles and El Kef, all representing outer neritic deposition in the same basin, the Tunisian Trough. Paleoenvironmental changes are explored by combining planktic foraminiferal, organic dinocyst and calcareous nannofossils assemblages and several proxy parameters (planktic/benthic ratio, numbers of planktic foraminifera per gram, peridinioid/gonyaulacoid ratio; terrestrial/marine palynomorph ratio). In addition, also some geochemical parameters (calcite content and stable isotopes) are examined. Our records indicate that the environment evolved from an initially oligotrophic, open marine, deep outer neritic setting in P2-P3a towards a shallower and nutrient-rich setting from the base of Subzone P3b. This change is seen in the foraminiferal assemblages, with the substitution of Praemurica by Morozovella among the planktic foraminifera and an upward decrease in deeper benthic taxa. Also the organic-dinocyst assemblages show a peak of peridinioid cysts (Cerodinium and Lejeunecysta). Associated to these dinocyst assemblages, the lowest occurrence of Apectodinium is recorded, which seem to have evolved in this region, possibly in response to enhanced nutrient levels on the shelf. Additionally, a distinct change in calcareous nannofossil assemblages is also described, marked by the lowest appearance of Chiasmolithus edentulus, the lowest consistent occurrence of Fasciculithus and a slight increase in near-shore taxa (essentially Pontosphaera).This project provides an accurate understanding of paleoenvironmental change across the Danian-Selandian transition in Tunisia. Especially, integrating different proxies demonstrates a paleobathymetric shallowing from the Danian to the Selandian, associated to increase surface paleoproductivity. Furthermore, the results are compared with those from other localities along the

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In the present study, we investigate upper Paleocene to lower Eocene planktic forami niferal assemblages in Egypt and Jordan across a middle neritic to upper bathyal transect of the Tethyan continental margin. In particular, we evaluate the planktic foraminiferal turnover across the Paleocene-Eocene Thermal Maximum (PETM). Dissolution affects the planktic assemblages more intensively than previously considered, especially in the marls below the PETM. High numbers of Subbotina, fl uctuating planktic/benthic (P/B) ratios, and low numbers of planktic foraminifera per gram (PFN) are indicative of dissolution, probably as a consequence of deep weathering. Hence, high numbers of Subbotina in this area do not indicate cooling. Despite this taphonomic overprint, we observe that well-diversifi ed planktic foraminiferal assemblages of Subzone P5a abruptly changed into oligotaxic assemblages dominated by Acarinina during the PETM. Because various biotic and geochemical proxies indicate increased nutrient supply to the basin, we argue that the blooming of Acarinina is not indicative of oligotrophic conditions. Instead, we postulate that (low-trochospiral) Acarinina may have been better adapted to thrive under stressed environmental conditions, possibly because they hosted symbionts different from those in Morozovella.