Milad Rezania ye Komachaly; Mojgan Salavati; Saeid Hakimi Asiabar
Abstract
Chamatoo intrusive body with monzonite to granite composition located south of Amlash city and east of Guilan in the Western Alborz. Petrographically, the Chamatoo intrusive body is ...
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Chamatoo intrusive body with monzonite to granite composition located south of Amlash city and east of Guilan in the Western Alborz. Petrographically, the Chamatoo intrusive body is mostly made of alkali feldspars and plagioclase with biotite, pyroxene, opaque minerals, and different textures from granular to porphyry granular as the main textures and perthitic, graphic, poikilitic as the accessory textures. In the chondrite-normalized spider diagram, the granitoid rocks display subparallel, linear and homogeneous REE profiles with LILE enrichment as well as Ta and Ti negative anomalies. In addition, all samples have the characteristics of WPG. Overall, the Chamatoo body was formed during the subduction of the oceanic crust of the Southern Caspian Sea and owing to the activity of an subducted mid oceanic ridge towards south, in an extensional regime above the supra-subduction zone a Slab Window was formed. Finally, Slab Window tectonic regime caused the rise of asthenosphere and the alkaline OIB magmatism in the region, followed by the generation of A1- type granite and the per-alkaline Chamatoo granitoid from fractional crystallization of OIB magma source.
