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The late Mesozoic-early Tertiary evolution of the eastern Mediterranean region was defined by a series of collisions between Gondwana-derived continental blocks and Eurasia as the intervening ocean basins closed. Prior to the terminal closure of these basins, subduction roll-back and associated extension/magmatism caused one or more episodes of arc splitting, producing SSZ oceanic crust with heterogeneous lithostratigraphy and geochemical fingerprints. Impingement of trailing continental margins with the trenches and subduction zones resulted in the cessation of slab rollback and in the entrapment of the protoarc-forearc oceanic crust as ophiolites in various collision zones. Following ophiolite emplacement, a series of collisional events (Paleocene-Eocene) between different continental fragments caused the formation of thick orogenic crust, high-standing plateaus, and heterogeneous mantle in the region. Collision-induced slab breakoffs provided heat and asthenospheric input that resulted in thermal weakening of the mountain belts and the onset of orogenic collapse, regional tectonic extension, and bimodal magmatism marked by linear distribution of granitoid plutons and high-K, shoshonitic to alkaline volcanics. The late Tertiary-Quaternary evolution of the region has been controlled by the generally northward motion of Afro-Arabia and the compressional tectonics induced by the convergence between Eurasia and Afro-Arabia. The collision of the Arabian promontory with Eurasia ca.
13 Ma facilitated the westward tectonic escape of Anatolia and caused intense deformation taken up by crustal shortening and conjugate strike-slip fault systems in a zone of ∼1000 km stretching from the Bitlis-Zagros suture zone in the south to the Greater Caucasus in the north. The Anatolian plate has been rotating counterclockwise relative to Eurasia during its escape to the west and hence has been experiencing internal deformation through a combination of strike-slip and normal faulting, including metamorphic core complex formation (i.e. Kazdag and Menderes massifs). Subduction rollback along the Hellenic Trench has been the driving force for this SW motion of Anatolia and the extensional tectonics affecting the Aegean province in the upper plate throughout the late Tertiary.
Widespread alkaline volcanism both in the Aegean extensional province and in the Turkish-Iranian plateau since the late Miocene shows chemical evidence for an enriched asthenospheric mantle melt source. The mantle response to the discrete collisional events, the geometry of colliding continental margins, and the scale of collisions strongly controlled the syn-to post-collisional tectonics and magmatism in the eastern Mediterranean region throughout the Cenozoic.
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