Petrography, geochemistry and tectonic setting of Rigi granitoid body (east of Lut Block, Central Iran)

The Rigi Granitoid Mountain is located in 5 Km West of Dehsalm and 85Km West of Nehbandan city, southeast of Birjand province and east of Lut Block. This granitoid with Eocene-Oligocene age was penetrated into sedimentary rocks (shale, limestone and sandstone) and changes theses rocks to skarn, hornfels and calcsilicate rocks. This granitoid consist of granodiorite, quartz monzonite and syenogranite with plagioclase, orthose, biotite, hornblende and quartz minerals. Sericite, chlorite, and Magnetite are secondary mineral in these rocks. Geochemical properties this pluton showes that it subalkaline and has metaluminous. Geochemical diagrams and presence of hornblende mineral in this pluton shows that belong to I-type granite. The rocks in granitoid pluton are enrichment LREE compare to HREE, high contents of LILE relative to HFSE and negative anomalies of Nb, Ti and P show it granitoid related to subduction zone. Also, tectonomagmatic diagrams improve that this pluton has belong to active continental margin.