Geochemistry and Petrogensis of Mafic Dykes of Zarrin District, NE Ardekan, Central Iran

Zarrin Mafic dikes, which outcrop in the Western Yazd block, Central Iran, trending NW–SE, emplaced into the Zarrin granitoid. They are sub-alkaline gabbro; characterized by intergranular and mylonitic foliated texture. Geochemical data reveal the Zarrin mafic dikes are from the partial melting lithospheric mantle, a spinel-peridotitic source. Furthermore, they are characterized by 87Sr/86Sr ratio of (0.7044-0.7028) and 144Nd/143Nd ratio of (0.5123- 0.5122), that consistent with the derivation from a lithospheric mantle. Their primitive mantle normalized trace elemental patterns display enrichment in LILEs compared to HFSEs, and positive Rb, Ba, and U but negative Ta, Nb, Th, and Zr anomalies, carrying characteristics subduction-related magmatism and metasomatism by subduction-related fluids. The petrogenesis of the Zarrin mafic dikes are related to melting of the lithospheric mantle, and upwelling asthenospheric mantle in the extensional basin which was associated with the subduction.