Mineralogy and Genesis of Joveinan Iron Skarn (Cenozoic Magmatic Arc, North of Isfahan)

Abstract

Joveinan marbles and skarns are located 5 km NE of Ghohrood and 140 km NW ofIsfahan in the *central part of Urumieh- Dokhtar magmatic arc. Intrusion of Ghohroodgranitoid into the Cretaceous carbonate rocks caused the contact metamorphism andformation of skarn mineral paragenesis wollastonite, clinopyroxene, garnet, actinolite,epidote, chlorite, calcite, quartz, magnetite and sulfides (iron and copper). Mineralogicalstudies and paragenetic mineral relations confirm that the Joveinan skarn is polygeneticin origin and evolved in two major stages, metamorphism and metasomatism(progressive and retrogressive). In metamorphism stage that occurred immediately afterthe granitoid magma emplacement within carbonate rocks, Joveinan marbles were formed. Metasomatic stage occurred with generation of anhydrous calc-silicatesminerals such as wollastonite, diopsidic-hedenbergitic pyroxene and ugrandite garnets.The main stage of retrograde metasomatic, alteration of primary calc-silicate minerals ofskarn (pyroxene-garnet), caused the formation of epidote, actinolite and chlorite. Theassociation of wollastonite, magnetite and andradite represents that skarn crystallized inover 550 ° C temperature range and low partial pressure of CO2. Joveinan skarn is acalcic skarn that has been formed at shallow depth by oxidative hydrothermal fluids andevolved in different stages.

Keywords

• Metasomatism
• Contact metamorphism
• Joveinan skarn
• North Isfahan magmatic arc