Petrography, Geochemistry and Mineralization of Pb in Hezarabad Area (Ashtian)

Hezarabad area is located 5 km at south east of Ashtian, Markazi Province. Structurally, the area is located in the Urmia-Dokhtar magmatic belt of Iran. The basement rocks of the area are pelagic limestone, lithic tuffs, and limestone to sandy limestone, marl, conglomerate, andesite lava and shale. Andesitic and tuff are the main host rock of mineralization. The mineralization mostly is vein types in four trends which follow NE-SW trend of local faults. The mineralization can be seen also as disseminated, breccia to fills fractures and pore-spaces types. The most important ore minerals are galena, cerosite and sphalerite. The galena is associated mostly barite in local faults. The second important mineral is sphalerite which can be seen mostly intunnels. 40 samples were analyzed by Inductive Coupled Plasma Mass Spectrometry (ICP-MS) for Pb, Zn, Ag, As, Cd, Co, Cr, Cu, Mo, Ni. The data processing indicates high anomaly for Zn and Pb and relatively anomaly for Cu, Ag, As, Mo. The average value of Pb is 34525 ppm and average value of Zn is 6108 ppm. The Mo content is reach up to 1182 ppm. According to correlation diagrams, there is a high correlation between Pb and Ag and also Ag and As. It shows that the galena is the main host of these elements.