Geochemistry and Petrogenesis of Shoshonitic Dyke Swarm in the Northeast of Meshkinshahr, NW Iran

The study area is located in Ardabil province the northeast of Meshkinshahr city. More than 200 small and large Eocene-age dykes form outcrops this area. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) U–Pb zircon analyses yield a consistent age 44.3 ± 1.8 Ma for dyke swarms. These include tephritic, andesitic basaltic compositions, show enrichment LREEs (relative to HREEs) are characterized by LILEs depletion HFSEs. Petrological observations, along with major, rare earth trace elements geochemistry, suggest that have shoshonitic signature. All rocks highly enriched incompatible variable Sr–Nd isotopes. Enrichment other geochemical features swarm metasomatized subcontinental lithospheric mantle magma source. negative Nb–Ta–Ti anomalies comparable subduction-related magmatism contamination ancient crustal components. radiogenic 87Sr/86Sr isotopic values imply involvement slab terrigenous sediments and/or continental lithosphere. Isotopically, volcanic exhibit binary trend, representing 1–5% mixing between primary sediment melts. Our melting models there residual garnet + spinel source, which partial amphibole- phlogopite-bearing lherzolites. geochronological, data swarms these Late Eocene magmas were derived from degree subduction-metasomatized source post-collisional setting.