First direct age determination from the Jurassic radiolarian-bearing siliceous series (Jédidi Formation) of northwestern Tunisia

Our study presents preliminary biostratigraphic results from the Jurassic siliceous series of northwestern Tunisia. For the first time, radiolarians are extracted from the Jédidi formation and provide a direct age determination. They are the first radiolarian fauna documented from Tunisia. Two age assignments are comprised within the following intervals: (1) Late Bathonian–Early Callovian, (2) Late Bathonian–Early Oxfordian. These ages are compatible with recent stratigraphic synthesis proposed for the Jurassic series of Tunisia. The data suggest the correlation of the Jédidi formation with siliceous series of Middle–Late Jurassic age from the external zone of the Maghrebides belt rather than with true oceanic units from the Maghrebian flyschs or the internal zones of western Tethys. To cite this article: F. Cordey et al., C. R. Geoscience 337 (2005).