Early Neoproterozoic rift-related magmatism in the Anti-Atlas margin of the West African craton, Morocco

• Published in: Precambrian research 2014-12, Vol.255, p.433-442
• Main Authors: Álvaro, J. Javier, Pouclet, André, Ezzouhairi, Hassan, Soulaimani, Abderrahmane, Bouougri, El Hafid, Imaz, Andrés Gil, Fekkak, Abdelilah
• Format: Article
• Language: English
• Subjects: Astenosphere upwelling; Lithosphere thinning; Mixed platform; Rodinia; Sciences of the Universe; Sequences; Tholeiitic basalt
• ISSN: 0301-9268; 1872-7433
• DOI: 10.1016/j.precamres.2014.10.008

•A Cryogenian tholeiitic magmatism is identified in the Anti-Atlas margin of the West African craton.•Magmatism is representative of a rifting phase derived from a spinel–garnet transition zone in the source.•Sedimentary lowstands consist of progradational fluvio-deltaic systems.•Transgressions and highstands recorded mixed peritidal to microbial reefal systems. The Moroccan Anti-Atlas contains the relics of a Tonian(?)-early Cryogenian rift developed along the northern margin of the West African craton. A distinct tholeiitic volcanic suite of lava flows, sills and dikes is encased in the Jbel Lkest Group (Kerdous inlier), the Taghdout Group (Zenaga inlier), the U1–U4 units of the Bleida-Tachdamt Group (Bouazzer Elgraara inlier), and the Lower Sedimentary Ensemble and Middle Volcanic Unit of the Tizi n’Taghatine Group (Siroua, Zenaga and Bouazzer Elgraara inliers). Two magmatic groups are distinguished that originated from a spinel–garnet transition zone ranging from zero garnet content to moderately enriched residual garnet content in the source, and partial melting degrees decreasing from 10% to 3%. Incompatible element patterns indicate contribution of both asthenospheric and lithospheric components suggesting an initial rifting geotectonic context, with lithosphere thinning and asthenosphere upwelling, similar to other complex systems of rifts that dissected Rodinia during the Early Neoproterozoic.