The Onshore Tunisia Numidian Flysch

The study concerns the Oligo-Miocene aged Numidian Flysch which forms the highest structural unit in northern Tunisia and consists of an interbedded unit of highly quartzose sand and shale, which are of turbiditic affinities. An integrated petrographic and geochemical study of this formation was carried out to infer the sandstones provenance, and reservoir characteristics. On the basis of the framework composition (point counting) and whole-rock geochemistry (major elements), the sandstones are classified as quartzarenite, and sublitharenite types. The modal analyses imply a recycled orogen provenance. Moreover, petrographic point count data indicate quartz-rich sedimentary (recycled), middle to high-grade metamorphic and plutonic parent rocks for Numidian sandstones. According to the plate and tectonic reconstructions of the western Mediterranean Sea it appears that the kabylean basement terrain cropping out along the Algerian coast and forming part of Calabro-Peloritani-Kabylian zone to be the parental source of the Numidian of both Sicily and Tunisia. Additionally, petrographical study indicates that the reservoir properties of the Numidian Flysch are a direct function of grain size and textural maturity.