Petrogenesis and isotopic age dating (uranium-lead) on zircon in granitoid body of metamorphic complex in Zul, southwest of Qaen, East of Iran

The present study is concerned with granitoid body crops out in a metamorphic complex occurring around Zul village of South Khorasan Province, eastern Iran. The complex is composed of migmatite, gneiss, mica schist, garnet schist, some marble and quartzite. Based on mineralogy, modal and geochemical data, Zul granitoid includes granite and granodiorite. These rocks are granular, graphic and porphyroid in texture. Major minerals are alkali feldspar, quartz, biotite and muscovite. Tourmaline, sphene, apatite, zircon and garnet are the minor mineral components. The granitoid is calc-alkaline and peraluminous in composition. Trace element data were normalized to average crust, showing enrichment in K, U and Th. These characteristics and negative anomaly for Eu can indicate melting of crustal sediments (S-type granitoid) in a collision-related tectonic environment.Isotope age dating on zircon uranium – lead indicates that, there are two generations of heritage and magmatic zircon in granitoid phase. Heritage zircon show 168.4 ± 2 Ma and magmatic zircon has 110.1 ± 1.5 Ma (late Early Cretaceous) age.