نوع مقاله : مقاله پژوهشی
نویسنده
گروه زمین شناسی معدنی و آب، دانشکده علوم زمین، دانشگاه شهید بهشتی
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
Late Miocene volcanic rocks of the northern Dehgolan area are located within the Sanandaj–Sirjan structural zone on the 1:100,000 Sanandaj geological map. The volcanic suite comprises andesite, dacite, trachyte, and latite. Andesites mainly consist of plagioclase, amphibole, and biotite and display porphyritic, trachytic, glomeroporphyritic, and sieve textures. Geochemically, the samples belong to the calc-alkaline, high-K calc-alkaline, and shoshonitic series and show a meta-aluminous character. Harker diagrams indicate decreasing FeO, CaO, TiO₂, and P₂O₅ and increasing Na₂O and K₂O during fractional crystallization, while trace-element scatter suggests additional magma mixing and crustal contamination. Primitive mantle–normalized spider diagrams show enrichment in LILE and LREE, depletion in Nb, Ti, and HFSE, and a positive Pb anomaly. Elevated Sr/Y and La/Yb ratios in some samples indicate an adakitic affinity, reflecting magma generation related to Neo-Tethyan slab melting or a metasomatized mantle source in an active continental margin setting.
کلیدواژهها [English]
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