Geothermometry ofskarns in the Nain ophiolitic m~lang.(Isfahan Province)

One of the metamorphic rocks in the Nain ophiolitic mclange is skarn which is fonned during the contact metamorphism of intrusive tonalites with their neighboring limestones and carbonate parts of banded cherts. Minerals of these skarns consist of carbonate (calcite). clinopyroxene (diopside). garnet (grossular-andradite). wollastonite, sphene and epidote. Also tonalites contain quartz, plagioclase (albite). alkali feldspar (orthoclase). garnet (almandine-spessartine) and prchnite, Based on mineral assemblages ofNain skarns as well as geothennometry of feldspars existing in relevant granites and also applications of different calibrations of garnet· clinopyroxene geothennometer. the Nain skams fonn at temperatures of about 440 to 650 °C al low pressure during a contact metamorphism which has occurred at hornblende hornfels to pyroxene hornfels facies.