Etude Géologique et Gîtologique de la Minéralisation à Pb-Zn-Ba et F d’Ain Kahla-Massif deHadjer Labiod (Monts du Hodna-Algérie Nord orientale)

Abstract

This work is intended as a contribution to the petrographic and mineralogical study of Ain Kahla lead-zinc mineralization, by determining the various textural types, the different existing minerals and paragenesis. The Ain Kahla deposit is located in the southern region of Sétif, about 08 km west of Ain Azel. Geologically, thedeposit is situated on the northern flank at the eastern end of the Hadjar Labiod massif, which represents the northern portion of the Hodna range. The Hadjar Labiod massif, belonging to the autochthonous external domain of the Maghrebos range, is an E-O oriented anticline, formed by sedimentary lands of Meso-Cenozoic age and cut by several faults of various directions. The lead-zinciferous mineralization of Ain Kahla is carried mainly by the dolomites of the of the lias medium-superior and of the dogger, it contains eleven ore bodies and is characterized by an essentially stratiform morphology, expressed by inter-stratified multilayer lenses. The petrographic study shows that the host rocks consist of several microfacies, mainly expressed by dolomicrite, dolomicrosparite, dolosparite and quartz dolomites. The geological study reveals the existence of several textures such as: texture in cauliflower, massive, disseminated, mottled, veined, brecchic, banded...... The metallographic and petrographic study shows that the mineralization has a simple paragenesis, composed of sphalerite, galena, barite, fluorite, pyrite, quartz, cerusite and hematite. The presence of these minerals allowed us to identify three paragenetic phases; a diagenite phase, an epigenetic phase and an alteration and oxidation phase. The mineralogical analysis by XRD confirms that the mineralization of the southern part of the Ain Kahla deposit is very rich in lead minerals.