Foraminiferal Biostratigraphy and Palaeoenvironmental Reconstruction of the Paleocene–Eocene Transition at the Kharrouba Section, Tunisia (Southern Tethys Margin)

Abstract

At Kharrouba (near Tunis City in northern Tunisia), on the southern margin of the Tethyan realm, the Paleocene-Eocene (P-E) transition interval deposition is continuous and complete. Based on high-resolution analysis and quantitative data of planktonic and benthic foraminifera at the Kharrouba section, this transition interval records expanded deposition of the relevant standard planktonic foraminiferal biozones with indicative index species i.e.: Morozovella velascoensis for the latest Paleocene P5 zone, and Acarinina sibaiyaensis for the earliest Eocene E1 zone, Pseudohastigerina wilcoxensis for the E2 zone, Morozovella marginodentata for the E3 zone and Morozovella formosa for the E4 zone. This complete section contains benthic foraminiferal assemblages which include calcareous and agglutinated cosmopolitan deep-water species (DWBF). Among the calcareous deep benthic foraminifera Aragonia velascoensis Anomalinoides rubiginosus, Oridorsalis umbonatus, Nuttallides truempyi, Pullenia coryelli and Tappanina selmensis, are relatively abundant. These species are the main representatives of the Velasco fauna indicative of a bathyal-abyssal environment. Moreover, within this section, the agglutinated species e.g., Glomospira charoides, Karrerulina horrida, Rzehakina epigona, Ammodiscus spp. and Gaudryina pyramidata, assumed to be restricted to deep-sea palaeoenvironments, constitute an important proportion of the benthic foraminiferal assemblages. Therefore, during the Paleocene-Eocene transitional period, the Kharrouba area hosted many cosmopolitan deep-sea benthic foraminiferal species as was the case at Zumaya and several DSDP sites. The depth range tolerances of these deep-marine taxa, both with calcareous and agglutinated test, indicate that close to the P/E boundary, the Kharrouba area was located in the lower bathyal environment in the southern Tethys margin.