Evidences of undependence of pillow basalt and dyke swarm of Nurabad-Miyanrahan Ophiolite (Kermanshah) to suprasubduction zone

The pillow lavas and dyke swarm of Harsin-Nurabad and Miyanrahan are part of Kermanshah Ophiolite complex. Diabasic dykes with ophitic, doleritic and glomeroporphyritic textures consist of zoned plagioclase and clinopyroxen and pillow lavas have intergranular and microporphyritic textures with hyalomicrolitic matrix and consist of plagioclase, augite-diopside and pseudomorphic olivines.The resalts of N-MORB-normalized multielement and chondrite-normalized REE patterns indicate that these rocks not formed in supra-subduction zone but overall geochemistry of Gashor pillow baslte and diabasic dykes resembles that of alkaline basalts generated at within-plate ocean island settings (OIB), meanwhile Tamark and Miyanrahan pillow baslte show P-MORB geochemical signature. MORB evidence in studied rocks is interpreted to be the partial melting of an OIB-type enriched source led to the production of the Gashor and diabasic dykes alkaline basalts whereas the partial melting of MORB-type mantle heterogeneously modified by OIB-type components resulted in the production of Tamark and Miyanrahan P-MORBs. Therefore, it may be considered that, southern Neo-Tethys was characterized by an intermediate rifted margin type where asymmetrical rifting, exhumed sub-continental upper mantle provided combination of continental margin- and plume-type in the investigated ophiolites.