Tectono‐sedimentary evolution of the ‘Numidian Formation’ and Lateral Facies (southern branch of the western Tethys): constraints for central‐western Mediterranean geodynamics

Terra Nova, 24, 34–41, 2012 Abstract The origin of the Numidian Formation (latest Oligocene to middle Miocene), characterized by ultra‐mature quartzose arenites with abundant well‐rounded frosted quartz grains, remains controversial. This formation, sedimented in the external domain of the Maghrebian Flysch Basin, displays three characteristic stratigraphic members with marked longitudinal (proximal–distal) and transverse (along‐chain) variations with palaeogeographical importance. The origin of the Numidian supply is related to the outward tectogenetic propagation when a forebulge evolved in the African foreland, leading to the erosion of African cratonic areas rich in quartzose arenites (Nubian Sandstone‐like). The ages of the Numidian Formation checked by Betic, Maghrebian and Southern Apennine data suggest a timing for the accretionary orogenic wedge, earlier in the Betic‐Rifian Arc (after middle Burdigalian), later in the Algerian‐Tunisian Tell (after late Burdigalian) and afterwards in Sicily and the Southern Apennines (after Langhian). A geodynamic evolutionary model for the central‐western Mediterranean is proposed.