Abstract
Since the 1970s, radiolarians have been used extensively to study and characterize basin successions from the peri-Mediterranean regions. However, no data was ever produced in Tunisia in spite of the occurrence of Jurassic siliceous series previously described by many authors. Our study presents the biostratigraphical results obtained on sections from the Jédidi Formation, which characterizes the basinal series of the Tunisian Trough. We provide new direct age determinations from the base, the middle part and the top of the formation, which ranges from the latest Bajocian–middle Bathonian to the Oxfordian (Tethyan biozones UAZ 5-6 to 8-9). The onset of these radiolarian-bearing series of the Tunisian Trough, adjacent to partly coeval Ammonitico Rosso successions, is interpreted as resulting from regional palaeotopographical gradient and palaeoceanographical conditions. Inaccurately interpreted as “true” radiolarites, theses series are different from coeval radiolarites of the Maghrebian “Dorsale calcaire” and from more recent homologous deposits of the Flysch domain. They are instead correlative with series exposed in the Babors and the west-Numidian ranges of northern Algeria that belonged to the same Jurassic North African margin of western Tethys. During Alpine convergence s.l., this external domain was overthrust by nappe complexes of the Maghrebide inner zones and the Flysch domain units.
Highlights
Over the last 50 years, Jurassic radiolarian-bearing siliceous successions from the circum-Mediterranean ranges have been well documented
In northern Tunisia, the Jurassic series of the Jédidi Formation (Fm) considered as “radiolarites” or “pseudoradiolarites” by the authors (e.g. Alouani et al 1990, Soussi 2002, respectively) have undergone various stratigraphic correlations, including controversial interpretations concerning the polarity of the Jurassic series to which they belong
We present here more complete results obtained at the type locality of the Jédidi Fm and other sections from the area
Summary
Over the last 50 years, Jurassic radiolarian-bearing siliceous successions from the circum-Mediterranean ranges have been well documented (see for instance synthesis by Bill et al 2001). Direct radiolarian age determinations are established at the base, the middle part and the top of the siliceous series. The Middle and Upper Jurassic successions of northern Tunisia are characterized by heterogeneous facies underlain by major discontinuities more or less marked from the Tunisian Dorsale to the Tunisian Trough (Fig. 2).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
