M Aghazadeh; Z Badrzadeh; A Castro
Abstract
The studied Roudbar and Abhar plutons are located in the western Alborz zone and Taroum subzone. These intrusive bodies show metaluminous and shoshonitic nature and they cut the Eocene volcanic and sedimentary rocks. In the studied plutons, monzonite and quartz monzonite terms are dominant. According ...
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The studied Roudbar and Abhar plutons are located in the western Alborz zone and Taroum subzone. These intrusive bodies show metaluminous and shoshonitic nature and they cut the Eocene volcanic and sedimentary rocks. In the studied plutons, monzonite and quartz monzonite terms are dominant. According to geochemistry, these plutons were crystallized from non-primary magma, and have been experienced fractional crystallization. In the primary mantle normalized spider diagrams and chondrite normalized REE diagrams, studied samples show clear enrichment in the LREE and LILE and depletion in the HFSE. The primary magma originated from 1-5% partial melting of phlogopite bearing lithospheric mantle with spinel lherzolite composition that metasomatized by subduction agents. According to U-Pb SHRIMP dating, these plutons were intruded during 37.8 to 38.9 Ma in the late Eocene and in a post-collision tectonic setting.
M. Aghazadeh; M. H. Emami; H. Moin Vaziri; N. Rashidnezhad Omran; A. Castro
Abstract
Khankandi pluton is located in northwestren part of Iran, within Garadagh (Arasbaran) - south Armenia block. Main units of the pluton are monzonite and granodiorite associated with minor gabbro and lamprophyric and dacitic dykes. Granodioritic plutonism is followed by gabbro and monzonite. Lamprophyric ...
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Khankandi pluton is located in northwestren part of Iran, within Garadagh (Arasbaran) - south Armenia block. Main units of the pluton are monzonite and granodiorite associated with minor gabbro and lamprophyric and dacitic dykes. Granodioritic plutonism is followed by gabbro and monzonite. Lamprophyric and dacitic dykes are emplaced at the end of the granodioritic plutonism. Gabbro and monzonites are shoshonitic, and granodiorites and dacites have high K-calc alkaline nature and charactistics of C-type (potassic or continental) adakites and high Ba-Sr granitoides. Lamprophyres are alkaline and have camptonitic composition. The monzonites follow fractionation trend of gabbro with minor crustal assimilation and contamination. Melting of garnet bearing mafic lower crust, metasomatised lithospheric mantle and upwelling asthenosphere produced granodioritic and dacitic, shoshonitic gabbro and lamprophyric magma respectively. The production of various magma types in the Oligocene of the Arasbaran occurred in response to slab break off and/or delamination of lithospheric mantle and upwelling of asthenosphere. Plutonism occurred after collision between Iranian and Arabian plates and crustal thickening in the extensional post collisional tectonic setting.
