The role of variscan shortening in the control of mineralization deposition in Tadaout-Tizi N’rsas mining district (Eastern Anti-Atlas, Morocco)

Authors : Mustapha AIT DAOUD, Abdelhafid ESSALHI, Mourad ESSALHI, Abdeslam TOUMMITE

Pages : 13-32

Doi:10.19111/bulletinofmre.524167

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Publication Date : 2020-04-15

Article Type : Research Paper

Abstract :The abundance of the NE-SW direction veins mineralized in barite, copper, lead and zinc in the Tadaout-Tizi n’Rsas (TTR) anticline make this area one of the principal vein fields in Tafilalet (easternmost border of the Eastern Anti-Atlas). Reactivation of faults and alternation of competent (thicks Ordovician series, Silurian limestone and Devonian limestone) and incompetent levels (Silurian shales and Devonian marls) have an important role in the deformation of the TTR anticline during the NE-SW Variscan shortening. Our work based on lineaments extraction using a Landsat 8 OLI combined with some geological cross sections, shows a N130° major fold corresponding to TTR anticline. This big fold shows internal N130°, N95° and N20° minor folds. This structure indicates that the TTR area was formed in the hinge between the Anti-Atlas and the Ougarta belts. A number of these folds are the consequence of the underlying Precambrian faults reactivation and alternation of competent and incompetent levels. Brittle tectonics is dominated by NE-SW normal faults which result from the NE-SW shortening consequence of the Gondwana and Eurasia continents collision. Consequently, the mineralization of TTR is necessarily related to late or post-Variscan orogeny.
Keywords : Eastern Anti Atlas, Variscan Shortening, Normal Faults, Tadaout Tizi nRsas Anticline