Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Magmatic Origin and Tectonic Setting of the Eocene - Oligocene Volcanic and Plutonic Rocks from the Zand-Abad Area, NW Ahar (Tarom-Qaredagh Zone)

Document Type : Original Research Paper

Authors
Z. Azimzadeh 1
M. H. Emami 2
R. Hajialioghli 3
1 Department of Geoloy, Natural science faculty, University of Tabriz, Tabriz, Iran
2 Research Institute for Earth Sciences, Geological Survey of Iran, Tehran, Iran
3 Department of Geoloy, Natural science faculty, University of Tabriz, Tabriz, Iran.
10.22071/gsj.2011.55053
Abstract
The Zand-Abad area is located in NW Ahar of north Azerbaijan. Magmatic rocks in this area consists of granitoids including monzogranite, granodiorite, monzonite and syenogranite as well as mafic rocks mainly diorite and associated extrusive rocks as andesite, trachyandesite, dacite, trachydacite, rhyolite. Subvolcanic rocks are porphyritic diorite and porphyritic monzodiorite. According to the different geochemical studies, the tectonic environment of Zand-Abad volcanic and plutonic rocks is determined as continental arc setting related to dilatory creep down subduction. This will be interpreted in relation with the Neotethyse post-collision activities. Considering the mineralogy and chemical evidence, we suggest that the Zand-Abad magmatic rock types (i.e. volcanic, sub-volcanic and plutonic rocks) have been derived from single magmatic source and undergone fractional crystallization, magma mixing and crustal contamination, resulting from hybrid granitoids. Magmatic series of the different types of magmatic rocks is alkaline. Calc-alkaline and shoshonite property of some samples is interpreted related to magma mixing and crustal contamination processes.  
Keywords
Dilatory Creep Down
Post-Collision Activity
Partial Melting
Fractional Crystallization
Magma mixing
Crustal contamination
Hybrid Magma
Zand-Abad
Tarom- Qaredagh zone
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Scientific Quarterly Journal of Geosciences
Volume 20, Issue 79
Winter 2011
Pages 113-120