Alteration, Mineralization and Geochemical Exploration (stream sediment and rock) of Eastern Najmabad, Ghonabad

The study area is located in Eastern Iran, 15 Km southeast of Gonabad. Low grade regional metamorphism (Jurassic-Cretaceous orogeny) has turned shale and sandstone of Jurassic into slate and quartzite. Slates are metamorphosed to different type of schist around the contact of granodiorite.Both magnetite and ilmenite granitoids were identified. Biotite granodiorite batholith belongs to ilmenite series. Monzonitic subvolcanic forms as stock and they are younger than granodiorite. Based on mineralogy and high values of magnetic susceptibility [(>500) × 10-5 SI], therefore monzonite is classified as belonging to the magnetite-series of oxidant type granitoids (I-type granitoids).Alteration zones associated with granodiorite are: sericitic, propylitic, silicification, argillic and tourmalinization. Heavy minerals (stream sediment) originated from granodiorite of the eastern section shows anomalies of Sn, Au, As, Pb, Zn, Cu, W. The highest values of these elements are: Sn = 445 ppm, Cu = 321 ppm, As = 399 ppm, W = 59 ppm, Pb = 980 ppm, Zn = 608 ppm.Analytical results of 77 samples taken from granodiorite and monzonite (altered and mineralized) show high anomalies of Sn, Cu, Au, Pb, Zn, W within granodiorite outcrop in the eastern section of the study area.