Petrography, geochemistry and source of Ghazan Plio-Quaternary basalts, NW Urmia

The volcanic rocks with the Plio-Quaternary age, are exposed in the northern part of the Sanandaj-Sirjan zone, in northwest Urmia. The main mineral phases are olivin + clinopyroxene ± plagioclase, that are present as both phenocrysts to microcrystalline with other minor minerals. The dominant textures of these rocks are porphyry, microlithic porphyry, hyalo-porphyry, glomeroporphyritic and vesicular. Based on geochemistry, the parent magma of these rocks are in the range of trachy-basalt to basaltic trachy andesite, belonging to the alkaline magmatic series. The mantel and chondrite normalised patterns of rare earth elements indicates the enrichment of LILE and LREE as well as the depletion of HFSE and HREE.The spider diagrams show a negative anomaly in Nb, Ta, P, Rb, Zr and Ti and positive anomaly in Pb, La, U, Nd, Th and Cs. These geochemical parameters and tectonic diagrams show that the Plio-Quaternary alkaline magmatism were formed in the post-collision arcs.