Mineralogy and geochemistry properties of Surma granitoids, Northeast Nehbandan, East of Lut block

Abstract: Surme granitoid plutons are located southeast of Southeastern Khorasan province and 50Km in Northwestern of Nehbandan city. Basd on geological of Iran classification this pluton is located at the junction of the eastern part of Lut and Sistan suture zone. The mass is composed of a small mass number such as stocks with the general trend northwest - southeast that interrupted flysch series and outcroup to Shemshak formation? Main body of pluton is Diorite and granodiorite composition. Plagioclase, quartz, alkali feldspar, hornblende and biotite are the main minerals component of this pluton. Surme granitoid is Calc- alkaline, metaluminous to peraluminous and I type. Depletion of Nb, P, Yb,Y and Ti elements suggest that the parent magmas relate to the subduction zone setting and affected by crustal contamination.These plutons have enriched in light rare earth elements (LREE) and depleted in heavy rare earth elements (HREE) with similar patterns.These characteristics indicate the likely origin of magma that originated from the subducted oceanic crust and metasomatisem with wedge mantle and finally contamination with crustal material. According to the tectonic discrimination diagrams surme granitoid has related to the active continental crust. Surme granitoid have low Sr (135- 205ppm), Sr/Y and plot predominantly in the field of mantle- derived arc magmas (normal Calc- alkaline rocks). Variations in Th/Yb and Ta/Yb ratios indicate that the resulted magma of granitoids unites have been affected by crustal contamination en route to the surface.