عنوان
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Zircon U–Pb ages, geochemistry and Sr–Nd isotopes of the Golshekanan granitoid, Urumieh–Dokhtar magmatic arc, Iran: evidence for partial melting of juvenile crust
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نوع پژوهش
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مقاله چاپشده در مجلات علمی
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کلیدواژهها
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Active continental margin, Granitoid, Sr-Nd isotope ratios, Juvenile crust, Neo-Tethys subduction, Urumieh-Dokhtar magmatic arc, Iran
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چکیده
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The Golshekanan granitoid body is situated in the central part of the Urumieh-Dokhtar magmatic arc (UDMA) in central Iran, and includes granite and granodiorite with minor monzonite and diorite. Zircon U–Pb dating yields a crystallization age of 37.6±0.2 Ma, Late Eocene (Priabonian). The body is calc-alkaline and metaluminous to weakly peraluminous (A/CNK≤ 1.10) with SiO2 ranging from 61.1 to 71.5 wt.% and MgO from 0.8 to 3.3 wt.% with Na2O+K2O of 4.0–8.5 wt.%. Primitive mantle-normalized trace-element patterns display enrichments in the large ion lithophile elements (LILE), such as Rb, Cs, Ba, and K, and depletion from the high field strength elements (HFSEs), such as Nb, Ti, Ta, and P. The rocks are enriched in LREEs relative to HREEs (Avg: (La/Yb)CN=4.3) and exhibit weak negative Eu anomalies (Avg: Eu/Eu* = 0.75), revealing typical active continental margin arc affinity. The low initial 87Sr/86Sr ratios (0.70440–0.70504) and notable positive εNd(t) values (+4.0 to +5.2) indicate an origin by partial melting of juvenile rocks in the lower crust and possibly with some involvement of sub-continental lithospheric mantle beneath Central Iran. These processes probably occurred due to the Neo-Tethys oceanic slab retreat and (or) rollback in the Late Eocene.
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پژوهشگران
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یوشی هیرو آساها (نفر ششم به بعد)، دیوید لنتز (نفر پنجم)، ونلی لینگ (نفر چهارم)، حاجی حسین عزیزی (نفر سوم)، بهاره زاهدی (نفر دوم)، فاطمه سرجوقیان (نفر اول)
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