Metamorphism of peridotites from Kal-e-Kafi area (Isfahan Province, Central Iran)

The Kal-e-Kafi area is located at 65th km of northeast of the Anarak city (Isfahan province). Metaperidotites of this area and associated Anarak Paleozoic metasediments are in contact with the Kal-e-Kafi Eocene intrusive body. Metaperidotites of Paleozoic age are remnants of the Paleo-Tethys oceanic crust. Petrography study shows that these rocks are consist of metamorphic minerals of olivine (forsterite-chrysolite) (CaO According to the results from the field study, petrography evidences, mineral chemistry and thermobarometry calculations, it can be concluded that peridotites of the Kal-e-Kafi area and Anarak sediments, have suffered a regional metamorphism in P-T condition of green schist facies in the Paleozoic, then in the Eocene the intrusive phases of the Kal-e-Kafi, caused to a progressive contact metamorphism in 680 to 770 °C and at pressure 0.5 kbar. This T-P conditions of metamorphism points to the metamorphism in pyroxene hornfels facies. Partial serpentinization of some metamorphic olivines and orthopyroxenes, and formation of late-stage chlorite around of some of tremolites, indicate occurrence of the retrograde metamorphism.