U–Pb geochronology of magmatic and detrital zircons (Zenaga and Bou Azzer-El Graara inliers, Anti-Atlas Belt, Morocco) and a reassessment of the published constraints suggest a revised stratigraphic framework for the lower Anti-Atlas Supergroup. Five major unconformity-bounded lithostratigraphic packages are here distinguished: the two lower units of Paleoproterozoic age are named the Tasserda-Taghatine Group (2030–1706 Ma) and the Oumoula (Mimount) Formation (ca. 1745–1650 Ma); the third unit of Paleoproterozoic to Neoproterozoic age (ca. 1650 to >883 Ma) is the Tizi n'Taghatine Group; the fourth and fifth units of Neoproterozoic age are the ca. 883 Ma Tachdamt and the ca. 700 Ma Bleida formations. Implications of this revised stratigraphic framework include: 1) the Tasserda-Taghatine Group might be linked to the post-orogenic collapse after the Eburnean Orogeny; 2) the Tizi n'Taghatine Group might be ca. 1.1 Ga in age based on proposed correlation with the Taoudeni Basin succession in Mauritania; 3) the Bleida Formation likely reflects deposition in the foreland basin at the early stage of the Pan-African Orogeny; 4) the Oumoula (Mimount) Formation, Tizi n'Taghatine Group, and Tachdamt Formation potentially record extensional events within the Nuna/Columbia and Rodinia supercontinents; 5) the provenance of the lower Anti-Atlas Supergroup (based on our new detrital zircon dating) is mainly from the West African craton along with possible contributions from other cratons such as Amazonia and the Sahara Metacraton; 6) the flood basalt sequence of the Tachdamt Formation likely belongs to the ca. 885-883 Ma intraplate Iguerda-Taïfast Large Igneous Province (LIP) event defined by previously dated dykes in the Iguerda and Taïfast inliers; and 7) the 1650 Ma Zenaga LIP can be potentially linked with LIP magmatism in Baltica and Laurentia.

Anti-Atlas Belt, Lower Anti-Atlas supergroup, Morocco, Proterozoic, U–Pb geochronology
dx.doi.org/10.1016/j.jafrearsci.2020.103946
Journal of African Earth Sciences
Department of Earth Sciences

Ait Lahna, A. (Abdelhak), Youbi, N. (Nasrrddine), Tassinari, C.C.G. (Colombo Celso Gaeta), Basei, M.A.S. (Miguel Angelo Stipp), Ernst, R.E, Chaib, L. (Latifa), … Bekker, A. (Andrey). (2020). Revised stratigraphic framework for the lower Anti-Atlas supergroup based on U–Pb geochronology of magmatic and detrital zircons (Zenaga and Bou Azzer-El Graara inliers, Anti-Atlas Belt, Morocco). Journal of African Earth Sciences, 171. doi:10.1016/j.jafrearsci.2020.103946