The Boukaïs inlier consists of a 2500m thick series of sedimentary rocks intercalated with lavas of basic to intermediate composition, crosscut by late dolerite dykes and dacitic intrusions. This volcano-sedimentary sequence forms part of a Late Neoproterozoic inlier located towards the northern boundary of the West African Craton in Western Algeria. In contrast to the NW Hoggar, further South and towards the Anti-Atlas chain further West, there is an obvious lack of field evidence for Pan-African events i.e.; (i) deformation, (ii) high to medium pressure metamorphism and (iii) subduction-related magmatism. This suggests that the Boukaïs sequence evolved after the main phase of Pan-African orogenesis (∼600Ma).Geochemical discrimination diagrams associated with detailed chemical analyses of the intercalated lavas and subsequent intrusions in the Boukaïs inlier, together with sedimentary features, suggest that this volcano-sedimentary sequence evolved during crustal thinning along the southern High Atlas Fault zone (HAF) during the late Neoproterozoic.