The Phanerozoic Evolution of the South-Tethys Domain from Morocco to Iran - Vertical Movements and Main Geodynamic Events

With the aim of giving an integrated tectonic scenario for the Northern African and Arabian plates, we revisit six key areas, namely, the Anti-Atlas Belt (Morocco), the Bechar Basin (west Algeria), the Hassi R’Mel High (central Algeria), the Talemezane Arch (south Tunisia), the Western Desert (Egypt), and the High Zagros Belt (Iran). Below the so-called “Hercynian unconformity,” which is in reality a highly composite discontinuity, surface and subsurface data display a well-known arch-and-basin geometry, with basement highs and intervening Paleozoic basins. We show that this major feature results mainly from a Late Devonian event and can no longer be interpreted as a far effect of the Variscan Orogeny. From the Jurassic, Pangea breakup has been diachronic and the Alpine-Tethys propagated through the development of two branches which will finally connect at the end of Jurassic times, achieving the development of Africa northern plate boundary. By the Late Cretaceous, convergence between Africa and Eurasia led to the progressive closure of the Tethys realm. Two major geodynamic events appear synchronous and occured during the Campanian-Santonian and the Middle-Late Eocene. These two synchronous events coincides either with a change in plate kinematics or with a period of strong lithospheric coupling.