Mineralogical characterization and structural control of the Tadaout-Tizi n’Rsas vein field (eastern Anti-Atlas Morocco)

The Tadaout-Tizi n’Rsas (TTR) polymetallic (Pb, Cu, Zn) vein field, located at the southeastern of the Moroccan eastern Anti-Atlas, is hosted in sedimentary sandstone formations of the Ktaoua Group of the upper Ordovician. These deposits are reported to be late Variscan to Post-variscan in age, and are related to the emplacement of late Permian doleritic magma event outcropping in the Tafilalet region. Structural and paragenetic studies of the TTR mineralization deposit were conducted in order to establish a general model of the mineralization. A two-stage model of the formation of the mineralized veins of the TTR vein field is proposed herein. The first episode is attributed to the late Variscan phase. It is a trantensive regime characterized by the presence of lenticular structures related to the normal dextral movement of the major faults. This episode is coeval with the emplacement and brecciation of the polymetallic mineralization of the TTR vein field (galena, chalcopyrite, sphalerite, and pyrite). The second episode is associated with normal faults, during the extensional phase corresponding to the tectonic relaxation of shortening (Upper Permian) and more probably during the Atlantic rifting. It is characterized by the formation of a banded texture of mineralization.