Writers : Ghasemi Barghi.A , Vosoughi Abedini.M ، Pourma'afi.M
Refference : Geosciences Scientific Quarterly Journal,No.:61,P.:92
Publishing Year : 1385

Abstract :
Over 300 small and large dikes are exposed in Moradloo district, covering an area of about 140 km2 in the north of Meshkin Shahr (NW of Iran). They dominantly oriented in NNE-SSW strike and intruded into the Lower Eocene volcanic breccias. Previous studies showed that the rocks were Pyroxene andesite and tephrite, regardless of geochemistry and geodynamics. Our petrographic studies indicate that there are at least 6 different petrological groups and magma mixing and contamination have played role in their formation. Geochemical diagrams not only emphasize the fractional crystallization as a principal process of magma evolution but also indicate their potassic and shoshonitic characteristics and generation by the low degree partial melting of LILE enriched source or metasomatized mantle materials. Finally discrimination diagrams show continental, post-collisional and island arc settings for their emplacement. Analyzing all data obtained shows that the petrogenesis and geodynamics of the dikes are accompanied with complex model in which the partial melting of metasomatized mantle wedge, the melting of ancient sub ducted oceanic crust, the interpenetrating of tectonic regime and finally the fractionation and evolution of parent magma in chambers or conduits have had significant roles.
Subject List : Petrography