Mineralogy studies and geochemical conditions determination of Pahnavar iron skarn, east of Jolfa
Pahnavar Fe skarn is located in northwest Iran at about 80 km from
Jolfa. The Intrusion of the Qolan igneous body into the Upper Cretaceous sediments with a Uthology of limestone, marl, shale and sandstone produced a thermal aureole with a considerable thickness. Also skarn mineralization including endoskarn and exoskarn has developed.
The exoskarn includes extensive garnet-pyroxene and epidote skarn zones. Petrographical studies, show that the presence of grossular-rich garnet in the garnet skarn and andradite-rich ones in the late-stage epidote-garnet vanes suggest composition changes of hydrothermal fluids during the intrusion and solidification of igneous body. Magnetite has replaced early skarn minerals in the first stage ofprograde skarn growth. The second stage of mineralization can be distinguished by crystalization of hematite, magnetite, pyrite, chalcopyrite, pyrrhotite, epidote, calcite and quartz as superimposed minerals. Epidote, Fe- chlorite, tremolite, ferroactinolite and calcite are common alteration products. According to mineralogical studies the Pahnavar skarn deposit is generated at a temperature 400 to 600°C,O2=10-15 –10-24,