Petrology and geochemistry of amphibolites from northwest of Salmas, NW Iran

Amphibolites crop out in the NW Salmas as two relatively small bodies around Abati and Ureban villages. Based on petrography and mineral paragenesis, the composition of Abati and Ureban amphibolites consists mainly of epidote amphibolite and amphibolite, respectively. Relict of clinopyroxenes from a parental rock are present in some samples. Mineral paragenesis (high hornblende and plagioclase and low quartz content) along with whole rock chemistry of the NW Salmas amphibolites show that the protolith was a basaltic composition with calc-alkaline to tholeiitic affinities. The original magmas of the NW Salmas amphibolites were not primary, and the composition of magmas has been modified by fractional crystallization and crustal contamination during ascending and emplacement. According to the discrimination and multi-element diagrams patterns (enrichment of LILEs in comparison with HFSEs and the negative anomaly of Nb and Zr), the parental magmas of the NW of Salmas amphibolites were generated in subduction-related tectonic settings.