Intrusive rocks petrogenesis related to the Gysian ophiolitic area, NW Iran

Igneous rocks associated with oceanic subduction have always been used as a key to understand the geodynamics of the ophiolitic regions. In this study, plutonic rocks of the NWIran, Gysian ophiolite were investigated to explore the relationship between different stages of the Neo-Tethyan ocean closure. Three reference regions (Zhar Abad, Susan Abad, and Darreh Bonar) with large outcrops of acidic and mafic rocks were the aim of this study which was classified as ZAG, SAG, and DBG. According to mineralogy, geochemical characteristics, and field evidence, these rocks are consistent with the three main groups of granitoids introduced by Barbarin (1999). The three identified groups MPG, ACG (or KCG), and PAG, in concordance with different stages of the Wilson cycle for ocean closures, can be used to investigate the development and geodynamic evolution of the region. During the subduction of the Neo-Tethyan oceanic crust under the Sanandaj Sirjan Zone (SaSiZ) and Central Iran microcontinents, ACG rocks were first formed as the SAG and the ZAG in a magmatic arc with the essential contribution of the upper crust, simultaneously with the continental-continental collision of the Arabian and Central Iran plates, MPG S-type leucogranites of SAG has arisen. Finally, at the post-collisional stage, the PAG (OIB-like) rock types are appeared in DBG due to the melting of the metasomatic mantle wedge along the thrust faults have raised from the fractures formed due to the regional tension during relaxation and crustal uplift.