Petrology, Geochemistry and Tectonomagmatic Setting of Kamtal Intrusion (North of Kharvana, Eastern Azarbaijan)
By: M .A. Mokhtari* , H. Moein Vaziri*, M.R. Ghorbani* & M. Mehr Parto**
Received: 2007 October 14 Accepted: 2008 May 13
Kamtal intrusion is located in East Azarbaijan province, NW of Iran, near the Armenia border. The Kamtal intrusion consist of an acidic part with monzogranitic composition and an intermediate- basic part which compositionally composed of monzonite, monzodiorite, quartz monzonite, quartz monzodiorite and gabbro. Gabbroic rocks exist in the form of small lenses in the southeast of Kamtal intrusion within the intermediate part. The intermediate- basic part has been intruded by the acidic part. Both acidic and intermediate parts are high-K calc-alkaline, metaluminous in character and classified as I-type granitoids; while, the gabbros have tholeiitic nature.
Both acidic and intermediate rocks show a LREE rich pattern and high LREE/HREE ratio. These two parts have differences in MREE enrichment. From similarity in REE patterns of acidic and intermediate rocks a genetic relation can be discerned. Negative anomalies of Nb and Ti can be seen in all rock phases of the Kamtal intrusion, representing the subduction zone setting. Comparison of trace element variations with those of granitoid rocks of different tectonic settings show similarities between Kamtal intrusion and Andean volcanic arc granitoids. Furthermore, Kamtal intrusion can be classified as VAG based upon tectonic setting discrimination diagrams. It is concluded that, Kamtal intrusion probably is the result of Neotethys oceanic crust subduction beneath the Caucasus continental plate.
Keywords: Petrology, Geochemistry, Batholith, Granitoid, Qaradagh, Kamtal, Kharvana, East Azarbaijan
* Geological Department, Tarbiat Modarres University, Tehran, Iran
** Research Institute for Earth Science, Geological Survey of Iran, Tehran, Iran