Mineralogical and Sulfur Isotopes in Ghar Roubane Barite Lead-Zinc Deposit, (Western Algeria)

The Ghar Roubane barite lead-zinc deposit lies in the metallogenic province of Western Algeria. This mineralization site occurs in the form of barite veins, taking place within the Paleozoic schists and granites and fracture-filling in Liassic limestones. The Paleozoic basement shows barite veins of several hundred meters in length, orientated from N50 degrees to N75 degrees, and dip mainly between 60 degrees and 90 degrees, with a thickness range comprised between 0.1 and 2 m. Barite pink, white to transparent in color. The barite veins are hosted in Liassic limestones with rare sulphides, related to fractures of NS and EW directions. The thermometric investigations performed on barite extracts from the granites indicate that homogenization temperatures (Th) for primary fluid inclusions appear to range from 130 to 140 degrees C. As for the barite extracts from schists and limestones, they display Th ranges ranging between 110 and 120 degrees C. Mean salinities are 15% equivalent NaCl for fluid inclusions in granite based barite, and 21% equivalent NaCl regarding the cover based barite. The interpretation of these data with respect to their relating geologic context favors a mixing process between basinal (prevailing) and basement fluids. The delta S-34 values relevant to the barite minerals prove to reveal a noticeable variation ranging from 21.3 to 29.4%. The sulfur isotopic compositions suggest that the ore-based formations turn out to be derived from different sources that may well include seawater along with magmatic fluid mixtures.