Lithostructural controls of Pb-Cu-Ag mineralized veins of Jbel Addana district (Western Anti-Atlas, Morocco): Implications for mineral exploration

Abstract

The Lower Paleozoic terrains of the Moroccan Anti-Atlas are known to host numerous Cu, Pb, Zn, and Ag occurrences, many of which are currently being explored and developed. The Jbel Addana district, which is the focus of this study, is situated in the western Anti-Atlas, at 35 km southeast of the Tagragra d’Akka Precambrian inlier. Structurally, it is an anticline predominantly composed of Upper Ordovician sedimentary Formations. These terrains host a network of Pb-Cu-Ag veins which are characterised by very old mining.

This study not only aims to integrate the Jbel Addana district into the regional tectonic and mining context but also to provide valuable insights for future mineral exploration and sustainable development in the Anti-Atlas region. The adopted methodological approach is essentially based on field investigations, geological mapping, structural analysis, and numerical processing of structural data using Win-Tensor software to understand the controls on mineralization.

The main results show that the mineralized bodies correspond to vertically dipping mineralized veins trending NNE-SSW and WNW-ESE. At the surface, mineralization is characterized by a supergene paragenesis comprising malachite, azurite, limonite, anglesite, and cerussite, while it is dominated by galena and a quartz gangue at depth. These mineralizations are hosted within fractures that crosscut the competent units, notably sandstones and quartzites, whereas they are almost lacking in the incompetent units, such as schists. The opening of these fractures is linked to the structural configuration of the Jbel Addana anticline, that conducted by the uplift of Precambrian basement blocks. This is caused by the inversion of the normal paleofaults of Upper Neoproterozoic-Lower Cambrian rifting into reverse faults during Hercynian orogeny.