گزارش مقدماتي از اكتشاف مس پورفيري در استان مركزي

Preliminary Report of Porphyry Cu Exploration at Central Province of Iran

Dalli mineralized area is located in Markazi province, about 200 km SW of Tehran within the Urumieh-Dokhtar Magmatic Arc. This mineralized area is hosted by andesite to dacite rocks that intruded into the volcanic rocks dominantly in andesitic composition and pyroclastics in miocene-pliocene age. In this area, igneous rocks have porphyritic texture and are composed mainly of biotite, amphibole, plagioclase, and quartz with variable amount of opaque minerals including dominantly pyrite, chalcopyrite and magnetite and secondary minerals such as epidote, calcite, chlorite, sericite. Geological and geochemical investigations show that mineralization in this area is of gold - rich porphyry Copper type. The content of Cu and Au is high wich is more than 0.75w% and about 1.2 ppm respectively. The mineralization is associated by felsic porphyritic igneous rocks and hydrothermal alteration such as potassic (secondary biotite, magnetite, and secondary k-feldspar), phyllic (sericite, quartz, and pyrite) and propylitic (calcite, chlorite, epidote...). The content of magnetite and stockworks of quartz - magnetite is high. These evidences can prove that Dalli mineralized area is a porphyry copper system.