Genesis of Golujeh Cu-Ag Vein Mineralization (N. Zanjan): Mineralogy, Geochemistry and Fluid Inclusion Evidences



Golujeh Cu-Au deposit is located in 45 km north of Zanjan city. Structurally it is part of Tarom-Hashtjin polymetal province in Alborz-Azarbaijan Zone of Iran. Based on 1:100000 quadrangle map of Hashtjin, the oldest exposure belong to Carboniferous limestone followed by Jurassic siltstone and shale, Cretaceous recrystalized low metamorphosed (Laramid orogenic phase) limestone. The igneous rocks are mainly volcanic and subvolcanic rocks of Eocene-Oligocene age, composed of tuff, ignimbrite, rhyolite, trachy-andesite, porphyritic andesite and rhyodacite. Major alteration assemblage is propylitic, argillic, sericitic and silicic alteration formed next to mineralized veins. The mineralization occurred along four major veins with average 2.5ppm Au, 0.6-1.5% Cu, 10ppm Ag, 2-3% lead and 1-2% Zn in hypogene and supergene suites. Hypogene minerals include magnetite, specular hematite, chalcopyrite, bornite, galena and sphalerite in association with cerusite, chalcocite, malachite-azurite, dijenite covelite and hemimorphite as supergene minerals.