Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Petrography, Geochemistry and Geodynamic of Moradloo Dikes , Northwest of Ardebil (NW Iran)

Document Type : Original Research Paper

Authors
Akbar Ghasemi Barghi 1
Mansour Vosoughi Abedini 2
Seyed Mohamad Pourma'afi 2
1 Payam-e-Noor University ,Ardebil Branch, Ardebil , Iran
2 Faculty of Earth Science , Shahid Beheshti University, Tehran, Iran
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 subducted oceanic crust, the  interpenetrating of tectonic regime and finally the fractionation and evolution of parent magma in chambers or conduits have had significant roles .
Keywords
Dike
Contamination
Fractional Crystallization
Shoshonitic characteristics
Geodynamics
Moradloo

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 16, Issue 61
Autumn 2006, Vol. 16, No.61
Autumn 2006
Pages 92-107