Mineral chemistry of clino-pyroxenes in gabbroic rocks from Darreh- Bid salt dome, Chaharmahal and Bakhtiari

The studied gabbroic rocks have exposures around Darreh-Bid salt dome. The rocks are located about 130 km south of Shahrekord (Chaharmahal and Bakhtiari Province).  The studied area is a part of Zagros structural zone. Mineral chemistry studies were done on clinopyroxenes in the gabbroic rocks of the Darreh- Bid salt dome. The clinopyroxenes are diopsid and augite and are plotted in low pressure field. The clinopyroxenes have been crystallized from magma with almost 10% H2O.  Pressure estimates from the clinopyroxenes in the range of <5kbar.  The magma has been rich in Ti and has MORB nature. Fe3+- values of the clinopyroxenes reveal high oxygen fugacity. The clinopyroxene composition yields the crystallization temperatures that range from 650-800 °C.