Résumé
The Bou Azzer inlier is thought to represent a suture zone within a Neoproterozoic orogeny. The Bou Azzer inlier is composed of an assumed ancient oceanic crust of serpentinized ultramafic rocks, gabbro and basaltic pillow rocks. This inlier hosts the Co-Ni ore deposit of Bou Azzer with two types of mineralization: i) massive, elongated ore bodies, known as "contact" type mineralization, along the contact between serpentinite, quartz diorite and Precambrian volcanic rocks; and ii) a "cross-cutting" type represented by faults that cut all units, only mineralized at the vicinity of the "contact" type. A detailed mineralogical and textural study brings new arguments on the ore -formation processes at Bou Azzer. First, it appears that both types of mineralization are developed within a progressive and continuous tectono-hydrothermal stage as shown by the mineralogical evolution. Second, the "contact" type exhibits two aspects: i.e., Laminated Contact Mineralization (LCM) and Breccia-Related Contact Mineralization (BRCM) that are related to different initial textures of the pre-mineralization host rocks. Third, Ni-Co mineralization seems to have developed by replacement of spinel/magnetite grains of the serpentinite. All these observations are consistent with ore formation along a tectonic contact which explains the existence of serpentinite fragments slope breccia.