University of Isfahan Petrological Journal 2228-5210 10 3 2019 11 22 Petrology, geochemistry and tectonomagmatic setting of Zajkan granitoid, Tarom-Hashtjin sub-zone, West of Qazvin Petrology, geochemistry and tectonomagmatic setting of Zajkan granitoid, Tarom-Hashtjin sub-zone, West of Qazvin 79 100 24413 10.22108/ijp.2020.118649.1147 FA Amir Abbas Seyedqaraeini Geology Department, Faculty of Science, University of Zanjan Mir Ali Asghar Mokhtari زنجان، دانشگاه زنجان، دانشکده علوم، گروه زمین شناسی 0009-0005-1226-5254 Hossein Kouhestani Geology department, Faculty of Science, University of Zanjan Journal Article 2019 08 07 Zajkan area as a part of Tarom-Hashjin magmatic belt contains some granitic intrusions which are intruded into the Eocene volcano-sedimentary rocks. Eocene volcano-sedimentary rocks include alternation of acidic to intermediate tuffs and lavas. Petrographical studies demonstrate that these intrusions composed of gabbro, pyroxene quartz monzodiorite, pyroxene quartz monzonite and granodiorite. These intrusions have high-K calc-alkaline nature and classified as I-type metaluminous granitoids. Based on the spider diagrams, these intrusions have similar patterns which are indicative for their genetic relation. These diagrams indicate enriched LILEs along with negative anomalies of HFSEs. Chondrite-normalized REE patterns demonstrate LREE enrichment with high ratio of LREE/HREE and (La/Yb)N ratio between 6.1-9.1. Based on field investigation, petrological and geochemical studies, and tectonic setting discrimination diagrams, it seems that Zajkan intrusions were formed from a subduction related metasomatized lithospheric mantle in a post-collisional setting. Zajkan area as a part of Tarom-Hashjin magmatic belt contains some granitic intrusions which are intruded into the Eocene volcano-sedimentary rocks. Eocene volcano-sedimentary rocks include alternation of acidic to intermediate tuffs and lavas. Petrographical studies demonstrate that these intrusions composed of gabbro, pyroxene quartz monzodiorite, pyroxene quartz monzonite and granodiorite. These intrusions have high-K calc-alkaline nature and classified as I-type metaluminous granitoids. Based on the spider diagrams, these intrusions have similar patterns which are indicative for their genetic relation. These diagrams indicate enriched LILEs along with negative anomalies of HFSEs. Chondrite-normalized REE patterns demonstrate LREE enrichment with high ratio of LREE/HREE and (La/Yb)N ratio between 6.1-9.1. Based on field investigation, petrological and geochemical studies, and tectonic setting discrimination diagrams, it seems that Zajkan intrusions were formed from a subduction related metasomatized lithospheric mantle in a post-collisional setting. https://ijp.ui.ac.ir/article_24413_f0ba039c1e89102ed5ff02b9eb829b36.pdf