The allochthonous Devonian of Azrou records the sedimentary and Eovariscan tectonic evolution of a source area near the northeastern margin of the Western Meseta. New conodont and microfacies data allow a revised lithostratigraphy, facies reconstruction, and interpretation of palaeogeography and synsedimentary tectonics. Three distinct successions are recognized in northwestern Azrou, central Azrou (Bou Ighial), and northeastern Azrou (Bab-al-Ari). In the northwest, the Bab-al-Ari Formation consists of unfossiliferous calcareous shales, overlain by the Azrou Formation, which comprises lower Emsian to upper Givetian limestones. Middle Givetian to lower Frasnian breccias with reef debris and large flat pebbles record seismic uplift, erosion, and downslope mass-flow redeposition from a partly lithified platform. At Bou Ighial, tectonic instability was even stronger, with long-lasting in-situ brecciation and thick gravity-flow deposits accumulating in a shale-rich shelf basin from the middle Givetian to the middle Famennian. The Bab-al-Ari type section also contains a local crinoidal limestone wedge, interpreted as a shoal within a shale basin, followed by renewed platform development in the lower Emsian. Later, block tilting led to alternations of shale, conglomerate, and breccia, while upper Famennian strata became strongly condensed and incomplete due to non-deposition or erosion. Comparison with neighboring regions shows that Azrou had a distinct tectono-sedimentary history, marked by especially intense extensional tectonics and two phases of sedimentary condensation or absence. The study also documents numerous new conodont, coral, bryozoan, and reef-builder records for the Meseta and North Africa, highlighting the biostratigraphic importance of the Azrou succession.
Aboussalam et al. (Thu,) studied this question.