Mineral prospecting and geochemical exploration in the block 1 (Kashan-Natanz-Tarq)
This block includes three 1:100000 sheets of Kashan, Natanz, and Tarq that totally reach to 7500 Km2 of Kashan Quadrangle. The block is situated in the Orumiyeh-Dokhtar volcanic belt which itself is located betweeb Sanandaj-Sirjan and Central Iran structural zones. Because a small portion in the southwestern study area is located in the Central Iran, the Precambrian and Paleozoic rocks in this domain show the Central Iran affinity. Existing rocks include Morad Series of Precambrian followed by Rizu and Dezu series that have sedimentary facieses; Soltaniyeh and Lalun (Cambrian), Niur (Silurian), Padha and Bahram (Devonian), Jamal (Permian), Sorkh shale, Shotori, Nyband (Triassic), Shemshak (Jurassic), Cretaceous conglomerate, limestone and shale. Tertiary rocks involve Eocene volcano-sedimentary rocks with sandstone, tuff, lava and conglomerate that are followed with Lower Red, Qom and Upper Red formation of Oligocene-Miocene. Pliocene is characterized by conglomerate. Holocene rocks include travertine, alluvial terraces, clay and salt flats.
The most important plutonism activity in the region is related to Qohrud-Qamsar-Vash intrusive rocks of middle Miocene with granite to granodiorite composition. All intrusive rocks are calkoalkaline that range from gabbro to granite. They trend along the Orumiyeh-Dokhktar zone correlating with important fault of Qom-Zefreh.
Mineralization is most of the area is related to the Qohrud-Qamsar-Vash intrusive rocks that caused skarn formation in their contact with older limestones. Due to hydrothermal activity of intrusive masses, vein deposit as Cu and Au-bearing silica viens also has occurred. Metallic mineralization in the Kashan 1:100000 sheet is mainly skarn and vein types. The Natanz and Tarq sheets mainly include vein type deposits as fracture and pore-filling ore deposits.
Important metallic minerals include iron, copper, cobalt, manganese, lead, zinc, nickel, antimony, silver and gold. Non-metallic minerals include barite, refractory, coal, silica, industrial soil, phlogopite, feldspar, zeolite, magnesite, fluorite, and building stone.
This project was conducted to control the anomalies introduced by GIS department of GSI. The metallic anomalies were identified by GIS analysis of geology, petrology, geochemistry, alteration and airborne geomagnetic data. Most of introduced anomalies are not economical. Application of prospecting report and filed studies was led to identification of several zones that should be studied in more details. Golestaneh-Hosseinabad in the Kashan sheet, Farizhand and Upper Jahaq in the Natanz sheet and Mozde are in the Tarq sheet contain favorable mineralization.