The Carboniferous formations of Migoumess, Tirhela and Idmarrach (central Morocco): lithology, biostratigraphy and geodynamic consequences

New biostratigraphical data based on foraminifers, algae and pseudo-algae indicate that the limestone pebbles of the channelized polygenic conglomerates of the Migoumess formation contain Late Visean (V3b<f>γ</f>–V3c) assemblages. That confirms the Westphalian age attributed to this formation by Hollard [Zdt. Geol. Ges. 129 (1978) 495–512]. The Tournaisian age assigned to it by palynology [C. R. Acad. Sci. Paris, se´rie II 310 (1990) 1573–1576] cannot be retained. The Tirhela formation, Late Visean and Serpukhovian (E1) in age, is coeval with the Akerchi formation [Berkhli, the&grave;se d'E´tat, 1999; Berkhli et al., J. Afr. Earth Sci. (accepte´)]. The Idmarrach formation, mapped as a thrust sheet [C. R. Acad. Sci. Paris, se´rie II 310 (1990) 1573–1576], is dated as Serpukhovian (E1) and its thrusting is consequently post-Serpukhovian. Palaeogeographic and geodynamic consequences are listed. To cite this article: M. Berkhli, D. Vachard, C. R. Geoscience 334 (2002) 67–72 [Copyright &y& Elsevier]