Paragenesis relations study of wollastonite – pyroxene – garnet mineral assemblage in Vejeh Skarn (North East Isfahan)

The Vejeh Skarn is located at 70 km Northeast of Isfahan. The Vejeh intrusive body with granodiorite to tonalite composition have been intruded the lower Cretaceous marl carbonate which caused the formation of skarn rocks. On the basis of field and mineralogical studies skarn type is calcic with low Mg amount. The mineral assemblage including wollastonite, pyroxene, garnet, epidote, quartz and calcite, have been taken place at progressive and retrogressive stages. Wollastonite and pyroxene (diopside – hedenbergite) were formed at primary progressive stage whereas garnet (grossular – andradite) was formed at secondary progressive stage through metasomatism of pyroxene and wollastonite. In the retrogressive stage with increasing ƒO2, the garnet was altered and replaced by epidote and secondary calcite and quartz. Regarding mineral assemblage it could be deduced the temperature of skarn formation have been reached to 500 -700 °C in the progressive stage and then decreased to 470 °C in the late stage