پيدايش ژاروسيت در گرانوديوريت هاي دگرسان قهرود

Jarosite occurrence in altered granodiorite of Ghohrud

Ghohrud intrusive body with tonalitic composition is formed by Miocene plutonism in central Iran and after Miocene time some parts of southern margins body have undergone hydrothermal alteration. On the basic of microscopic investigations this alterations includes: silicification, cericitization, tourmalinization and jarositi-zation. The latest alteration processes are silicification and formation of jarosites with iron oxides. Formation of jarosite related to oxidation of pyrite and acidic environmental in granodioritic rocks. In this acidic environmental the required Na for jarosite formation has been prepared by feldspar alteration. Geochemistry of jarositic rocks has shown anomaly of Pb, La, Ba, Ca, Na and Ce.