Petrological and geochemical constraints on the evolution of the Cheshmeh-Sefid granitoid complex of Golpayegan in the Sanandaj-Sirjan zone, Iran

The Cheshmeh-Sefid granitoid complex, hosted by metasedimentry and meta-igneous rocks, north of Golpayegan, Sanandaj-Siran zone of Iran, is a heterogeneous pluton that comprises mainly quartz-monzonite, quartz-syenite, granite and syenite rocks. Geochemically, the granitoids are mostly peralkaline to metaluminous. They have similar trace element abundances over a range of SiO2 from 57 to 72.4 wt.%, and have a distinctive A-type chemistry characterized by high contents of Na2O + K2O, Nb, Zr, LREE and low MgO. The P-T conditions of crystallization of the granitoids were determined from amphibole-bearing samples using amphibole-plagioclase thermometry and Al-in-hornblende barometry. Aluminum-in-hornblende geobarometry indicates crystallization pressures of about 5 to 6 kbar; corresponding to intrusion depths of 17 to 20 km. Hornblende-plagioclase geothermometry indicates hornblende crystallization temperatures of 750 to 790 degrees C. Also, the Zr saturation temperature based on zircon solubility reflects a mean temperature of 776 degrees C.