Typology and tectonic setting of the Qorveh granitoid (Kurdistan Province, western Iran)

The south Qorveh granitoid plutons (Kurdistan) which have intruded into the regionally metamorphosed rocks (Kimmerian Orogeny) lie in 80 km NW of Hamedan city. They composed predominantly of granodiorite and granite with minor amount of diorite and gabbro. Field characteristics (i.e. absence of migmatite), as well as several petrographical and geochemical features including the presence of Ca-plagioclase, magnesio-hornblende, and the lack of Al-bearing minerals (i.e. corundum, muscovite), the ASI>1, mol Na+K>mol Al, ratio Na2O+K2O-CaO/SiO2, decrease of P2O5 in Harker diagram, as well as high abundances of Na and Ca are in favor of I- composition of the parent magma. To determine the tectonic setting of the Qorveh granitoid plutons, several diagrams are used including Rb/10-Hf-Ta*30, La/Yb vs. Th/Yb, Th/Ta vs. Yb, spider diagram, and also discriminating diagrams for tectonic environment. Using Agrawall, the studied granitoid has R>0 and so it is an orogenic granitoid. The studied samples generally reflect the volcanic arc setting in active continental margin and it is similar to late- orogenic granitoids. Investigation of tectonic setting and age of granitoids in Sanandaj-Sirjan Zone (SSZ) show that the granitoid developed by subduction of Neo-Tethyan oceanic crust underneath Central Iran.