Nouvelles données biostratigraphiques sur les niveaux de passage Jurassique- Crétacéet les calcaires du Campanien dans le secteur de Hammam Zriba- Jebel Guebli (Tunisie septentrionale) New biostratigraphic data on the Jurassic-Cretaceous boundary and the Campanian's limestone in the area of Hamma... (original) (raw)

The biostratigraphical study, based on the calpionellids and foraminifera, of the Jurassic-Cretaceous boundary in the sector of Hammam Zriba-Guebli (Northern Tunisia), leads to precise the age and facies of ante-Campanian limestones. These limestones, which characterize pelagic facies in the Jebel Guebli cross section, were attributed to the Tithonian. In this study, the recorded calpionellids allowed us to give an upper Tithonian, Berriasian and lower Valanginian age. In the Hammam Zriba cross section (1 km northern side) the neritic facies rich in algae and benthic foraminifera characterize the Jurassic-Cretaceous boundary. The juxtaposition of these two facies shows a horsts and half grabens structuration characterizing Jurassic-Cretaceous boundary in this sector. The Campanian transgressive limestone has provided planctonic foraminifera with Globotruncana genus characterizing lower to upper Campanian. Résumé: L'étude biostratigraphique basée sur les calpionelles et les foram...