Northern Tunisian Lower Cretaceous Stratigraphic Approach Using Ammonites and Microfaunas: A Model for the Tethys Southern Margin
During the Early Cretaceous, an open-marine basin, the “Sillon tunisien” (=Tunisian Trough), occupied the north of Tunisia. Situated on the meridional edge of the Tethys Ocean, it was marked by active tectonic subsidence. The great thickness and the lithology of the sediments were influenced by the Tethys transgressions initiating from the northwest, which deposited deep-marine (circalittoral and bathyal) shaly units with limestones, and by Saharan detrital sediments prograding from the southwest. Lower Cretaceous rocks are represented by thick sequences of shales with thin beds of limestones and sandstones on the western side of the basin. Neverthless, on the eastern side, the series are thinner due to positive movements of the basement along the “Zaress–Zaghouan axis”. The series contain nektonic faunas (ammonites) and planktonic fauna (calpionellids and foraminifera) which allow us to establish biostratigraphic scales. Recognized biozonations are integrated into the general scheme developed for the Mediterranean Province (ammonites) and the Mesogean areas (planktonic foraminifers), and a correlation between the two zonations is presented.
KeywordsLower Cretaceous Biozonations Correlation Northern Tunisia
- Ben Haj Ali, N. (2006). Les Foraminifères planctoniques du Crétacé inférieur de la Tunisie septentrionale. International Conferenceon theGeologyof theArab World(GAW8), Cairo University, pp. 609–617.Google Scholar
- Ben Haj Ali, N. (2008). Synthèse stratigraphique et nomenclature pour le Crétacé inférieur de la Tunisie septentrionale. Notes du Service Géologique Tunisie,76, 165–181.Google Scholar
- Memmi, L. (1989). Le Crétacé inférieur (Berriasien-Aptien) de Tunisie. Biostratigraphie, Paléogéographie et Paléoenvironnements. Thèse Doct. Ès- Sciences, University of Lyon 1, p. 158.Google Scholar