Petrography and chemistry of minerals showing that Eocene alkaline volcanic rocks in southwestern of Germi (Talesh zone, NW Iran) mostly have basaltic composition. Mineralogically these rocks are composed of diopsidic clinopyroxene and labradoritic plagioclase phenocrysts. The microlithic and glassy groundmass composed of sanidine, clinopyroxene, biotite, pargasitic amphibole and magnetite associated with devitrified glass. Clinopyroxenes show relatively high Mg-numbers (0.76-0.93), low AlVI (mostly <0.1), suggesting relatively low-pressure (~5), and water content ~2.5 to less than 10% and high oxygen fugacity (-8.38-11.51) of crystallization condition. High amount existence of magnetite coexisting with amphibole and biotite mineral confirm high fugacity of the host magma. According to clinopyroxene and feldspar thermometry, estimated crystallization temperature varies between 1106˚C to ~1200 ˚C. The clinopyroxene and amphibole mineral composition of studied rocks indicate that they have been formed in a back-arc basin environment. Mineral chemistry in the current zone shows that composition and genesis of common minerals these magmatic rocks are similar to Pushtasar basaltic rocks in the northern part of this area. پرونده مقاله

The studied area is as a small portion of Sanandaj - Sirjan Zone (SSZ). Metamorphic rocks in this area subdivided to 2 groups on their setting: Regional and Contact. Slate and Phyllite are petrographic facieses of regional metamorphism. This metamorphism has affected a vast area and is of low grad in green schist (Chlorite Zone). The Boroujerd granitoid massif is elongated and parallels the prevailing schistose in these rocks by the trend of NW-SE. By the injection of it, a contact metamorphism has occurred which can be considered as a pyroxene hornfels facies. Contact metamorphic rocks, consisting of spotted schists, hornfels-schist, hornfelses and migmatites, are evident only to the north of the pluton, because the southern margin of it is controlled by a fault system parallel to the contact and the granitoid rocks are thrusted onto the metamorphic rocks. Field and microscopy evidence show that migmatites are injective and occurred by intrusion of granitoid magma into metamorphic rocks. Calculation of garnet-biotite thermometer by all of the average calibrations, account 472° C for equilibrium this two minerals in hornfels. پرونده مقاله