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    المساهمون: İstinye Üniversitesi, Mühendislik ve Doğa Bilimleri Fakültesi, Bilgisayar Mühendisliği Bölümü, Hüseyin Ozan Tekin / 0000-0002-0997-3488, Tekin, Hüseyin Ozan, Hüseyin Ozan Tekin / J-9611-2016, Hüseyin Ozan Tekin / 56971130700

    المصدر: Open Chemistry. 20:169-181

    وصف الملف: application/pdf

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    المساهمون: Nasrabady, Mohsen, Shi, Yuruo, Lustrino, Michele, Rossetti, Federico

    المصدر: Geochemistry. :125962

    مصطلحات موضوعية: Geophysics, Geochemistry and Petrology, The Sabzevar ophiolites, located at the northern margin of the Central-East Iranian microcontinent (CEIM), are part of the Mesozoic-Paleogene Neotethyan suture zone developed along the Alpine-Himalayan convergence zone. These ophiolites consist mostly of oceanic lithospheric remnants, covered by early Campanian-late Maastrichtian volcano-sedimentary successions. A distinctive characteristic of the Sabzevar ophiolites is the occurrence of mafic dike swarms (gabbros, gabbronorites and diorites) with forearc-arc-tholeiitic geochemical signature, intruding the mantle section. Occurrence of orthopyroxene, development of pegmatitic texture, crystallization of clinopyroxene prior to plagioclase, and the presence of anorthite-rich plagioclase imply relatively high H2O content in the magmatic plumbing system. Rare plagiogranites (tonalite and trondhjemite compositions) show geochemical features compatible with a supra-subduction setting, whereas late (hornblende-bearing) gabbro dikes show a within-plate signature. The bimodal geochemical affinity (subduction vs. intraplate) is also attested by clinopyroxene compositions. The gabbroic, plagiogranitic and gabbronoritic samples yield Early Cretaceous SHRIMP zircon U-Pb ages of 96.7 ± 1, 98 ± 1 and 94 ± 1 Ma, respectively. A progression from tholeiitic MORB-like to more depleted high-Mg andesite and eventually alkaline affinities is here proposed, framing the magma evolution as generated in an evolving forearc setting that post-dated (of at least 9 Myr) the formation of the metamorphic sole during the infant stages of subduction of the Sabzevar Ocean. A scenario of far-field forced subduction initiation of the Sabzevar Ocean is proposed as consequence of propagation of the residual stresses transmitted from the Arabia-Eurasia convergence zone across the CEIM during Cretaceous times (Albian-Campanian)

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