Petrographic, mineralogical and geochemical characterization of The Tidiennit volcanic complex (eastern Rif)

Abstract

The Tidiennit massif corresponds to a volcanic apparatus that represents one of the two known neovolcanic manifestations in the Nador region (north-east Morocco). It is a satellite volcano of the neogenous volcanic edifices of Gourougou (high-K calc-alkaline to shoshonitic), which is characterized by the presence of various deposits of useful mineral substances (bentonite, perlite). The studies carried out on the Tidiennit massif focused on the bentonites of the three sectors of Prévidencia, Trébia, and Taghzoute. The results obtained by EDAX/MEB show that the main components of bentonite are generally: montmorillonite, illite, calcite, hematite, sepiolite, fayalite, albite, biotite, orthose, cristobalite, and calcite, with montmorillonite accounting for a sizable portion of 80%. The studied region was affected by intense striking tectonics. The petrographic analysis of the rhyolitic magma highlights the superposition of two fluidity phases, one linear and the other nested, which is suggested the passage from a plastic to a brittle deformation stage. This favored the evolution of a set of structures and microstructures that facilitated the circulation of water, which allow us to conclude the origin of meteoric and hydrothermal alteration, and that bentonitization (alteration) is closely linked to the lithological characters of the rocks.