نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشگاه اصفهان گروه زمین شناسی
2 دانشگاه اصفهان
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The Neybaz high-grade metamorphic complex is located in the western domain of the Central Iranian microcontinent, situated between the two basement faults of Chatak-Neybaz and Chapedony. Within this complex, metamorphosed mafic rocks are found as small masses in contact with and within gneisses that exhibit granulite facies metamorphic grade. The high-grade metamorphism in these rocks led to the appearance of a mineral paragenesis primarily composed of clinopyroxene and orthopyroxene, euhedral garnets, amphibole, and plagioclase.
Geochemical investigations of these granulites indicate that their protoliths ranged from basalt to andesite and basaltic andesite, showing a calc-alkaline and tholeiitic affinity. Lithogeochemical variation diagrams suggest that these rocks formed in a plate margin setting. Furthermore, the close association of the mafic granulites with gneisses, some of which have a metagraywacke protolith, points to their origin from an active plate Margin.
Spidergrams normalized to the primitive mantle and chondrite show enrichment in light rare earth elements (LREEs) relative to heavy rare earth elements (HREEs), enrichment of LIL elements, and depletion of HFS elements, confirming the involvement of both mantle and crustal sources in the formation of the protoliths.
Based on the geochemical data and structural evidence, this study suggests that the formation of the mafic melts in the Neybaz complex was related to cratonization processes in an active margin environment during the Paleo- to Neoproterozoic era. The geochemical characteristics of these granulites, including negative Nb and Ti anomalies in the spidergrams, link their origin to arc magmatism (such as island arc tholeiites or calc-alkaline basalts).
کلیدواژهها [English]
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