STABLE S-, O- AND C-ISOTOPES IN THE GRANITOÏDES OF NORTHEASTERN ALGERIA: ORIGIN OF MAGMAS AND RELATED MINERALIZATION

Abstract

The Miocene magmatic event in northeastern Algeria is a consequence of the western Mediterranean subduction-collision between the African and European plates during the Oligo-Miocene. This event was accompanied by the emplacement of a number of economic and non-economic ore bodies that show variable nature (Pb-Zn- Cu, As-Au, Sn-W) and different emplacement styles (veins, masses, disseminations). The petrology and geochemistry of the igneous rocks shows that the majority of the magmas are calc-alkaline and originate from the lower crust or upper mantle source region (I-type). Mineralization hosted by the igneous bodies show also a magmatic signature for the mineralizing fluids through their stable S-, O- and C-isotopic compositions. On the other hand, mineralization hosted by the country rocks shows a crustal origin of the mineralizing fluids; the igneous activity being the heat engine for the crustal fluids.