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Early Cretaceous migmatitic mafic granulites from the Sabzevar range (NE Iran): implications for the closure of the Mesozoic peri-Tethyan oceans in central Iran |
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| Authors: | Federico Rossetti Mohsen Nasrabady Gianluca Vignaroli Thomas Theye Axel Gerdes Mohammad Hossein Razavi Hosein Moin Vaziri |
| Institution: | Dipartimento di Scienze Geologiche, UniversitàRoma Tre, 00146 Roma, Italy;;Department of Geology, Tarbiat Moalem University, Tehran, Iran;;Institut für Mineralogie und Kristallchemie, Universität Stuttgart, 70569 Stuttgart, Germany;;Institut für Geowissenschaften, J. W. Goethe Universität, D-60438 Frankfurt, Germany |
| Abstract: | The ophiolitic mélange of the Sabzevar Range (northern Iran) is a remnant of the Mesozoic oceanic basins on the northern margin of the Neotethys that were consumed during the Arabia–Eurasia convergence history. Occurrence of km-scale, dismembered mafic HP granulitic slices is reported in this study. Granulites record an episode of amphibole-dehydratation melting and felsic (tonalite/throndhjemite) melt segregation at c. 1.1 GPa and 800 °C. In situ U(-Th)–Pb geochronology of zircon and titanite grains hosted in melt segregations points to an Early Cretaceous (Albian) age for the metamorphic climax. Results of this study (i) impose reconsideration of the current palaeotectonic models of the Neothetyan convergent margin during the Early Cretaceous and (ii) argue that punctuated events of subduction of short-lived back-arc oceanic basins accompanied the long-lasting history of the Neotethyan subduction in the region. |
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