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The Oligocene Nasrand intrusive rocks (NIRs), located in the central part of the Urumieh–Dokhtar magmatic arc, are mainly composed of granite and subordinate diorite and gabbro. These rocks are characterized by the enrichment of light rare earth elements (LREEs), Nb‐Ta negative anomalies, and high LILE/HFSE, suggesting a subduction‐related origin. The felsic rocks with granite compositions have high SiO2 content (69.77–77.88 wt.%), low Mg# (0.02–0.43), low Nb/Ta, and Zr/Hf (Avg: 12.53, and 33.08, respectively). The initial 87Sr/86Sr ratio and εNd(t) values in felsic rocks range from 0.70577 to 0.70576 and 0.4 to −0.3, respectively. These data suggest that these felsic rocks originated from juvenile crust by heat rising from basaltic magmas in an orogenic setting. The mafic‐intermediate rocks and dikes are gabbro, gabbroic diorite, and monzodiorite, with low SiO2 content (48.08–56.11 wt.%) and high Mg# (0.37–0.68), with average ratios of Nb/Ta and Zr/Hf are 27.88 and 39.84, respectively. The initial 87Sr/86Sr ratio and εNd(t) values for mafic‐intermediate rocks and dikes are 0.70583 to 0.70476 and −0.1 to +2.6, respectively. These characteristics indicate magma from a mantle source that had undergone minor mixing with juvenile crust. It seems mantle‐derived juvenile magma underplating played an important role in the crustal growth in the Urumieh–Dokhtar magmatic belt during the Ediacaran to Early Cambrian, relative to other time frames. [ABSTRACT FROM AUTHOR]

Abstract: The Astaneh plutonic complex consists of a series of granitoid rocks ranging in composition from quartz-diorites to monzogranites and evolving from metaluminous to weakly peraluminous compositions. They belong to the high-K calc-alkaline series, having features of typical Andean-type cordilleran granitoids. Trace and rare-earth elements distribution patterns for the Astaneh rocks indicate a distinctive depletion in Nb, Sr, Ba, P and Ti relative to other trace elements and a greater enrichment in LILE compared to HFSE. These geochemical characteristics suggest the participation of an important recycled (sedimentary?) component in the source region of the granitoids. They have Sr initial isotopic ratios in the range 0.7078–0.7084 and negative ε Nd values of −5.39 to −6.13 for a time of generation of 170Ma. There is a genetic link between quartz-diorites and granodiorites, the dominant rock types of the Astabeh intrusion. Direct melting or fractionation from a diorite source is very unlike. It is proposed that the Astaneh parental Qtd-diorite magmas were produced by the partial melting of a mixed source, dominantly composed of amphibolites and sediments, that was formed during subduction of Neo-Tethyan oceanic crust below the Iranian microcontinent during Middle Jurassic times. [Copyright &y& Elsevier]