The deformation history of the Neoproterozoic Central African Orogenic Belt in southern Cameroon is well recorded in the low- to high-grade rocks outcropping in the area around Yaoundé. The fabrics in these rocks are consistent with two main ductile deformation events D1 and D2. D1 predated emplacement of calc-alkaline dioritic bodies and caused the formation of nappes that resulted in high-pressure granulite metamorphism of soft sediments. A strong overprinting of these nappes during D2 symmetric extension, probably associated with large-scale foliation boudinage and (or) gneissic doming and intense magmatic underplating, gave rise to regional flat-lying fabrics. The latter were further buckled by D3 and D4 folding phases defining a vertical constriction occurring with a major east–west to NW–SE shortening direction. The corresponding F3 and F4 folds trend north–south to NE–SW and east–west to NW–SE, respectively, and represent the main regional strain patterns. Based on the east–west to NW–SE maximum shortening orientation indicated by F3 folds, it is proposed that the nappe-stacking phase D1 occurred in the same direction. The deformation history in the area can thus be described as corresponding principally to alternating east–west to NW–SE contractions and north–south to NE–SW orogenic-parallel extensions. At the regional scale, this could be due to the Transaharan east–west collisional system.

The foliations, lineations, fold axes trajectories and shear zones kinematics vary from the Archean Ntem and Paleoproterozoic Nyong complexes to Neoproterozoic Oubanguide complex. The S 1 , S 2 and S 3 typified foliations are folded in F 2 , F 3 and F 4 cartographic folds equivalent to thrust slices while the L 1 , L 2 and L 3 lineations are oriented SSE-NNW, westeast and sub-north-south in the above complexes, respectively. Both, the foliations and lineations confirm the transport top-to-the east of the Nyong nappe onto the Congo craton during the Eburnean orogeny under amphibolitic conditions and as the transport top-tothe SSE of the Yaounde nappe onto the Ntem and Nyong complexes during the Pan-African event under granulitic to green schist conditions. The paleostress of fault and shear zones display crustal thinning and horizontal extension oriented east-west, NW-SE and subnorth-south in the Ntem, Nyong and Oubanguide complexes. All these tectonic features, completed by north-south and east-west cross sections, demonstrate litho-chronostratigraphical, structural and angular discordances between the three complexes.

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