PT - JOURNAL ARTICLE AU - Kazemi, Zakie AU - Ghasemi, Habibollah AU - Tilhac, Romain AU - Griffin, William AU - Moghadam, Hadi Shafaii AU - O'Reilly, Suzanne AU - Mousivand, Fardin TI - Late Cretaceous subduction-related magmatism on the southern edge of Sabzevar basin, NE Iran AID - 10.1144/jgs2018-076 DP - 2019 Jan 01 TA - Journal of the Geological Society PG - jgs2018-076 4099 - http://jgs.lyellcollection.org/content/early/2019/01/31/jgs2018-076.short 4100 - http://jgs.lyellcollection.org/content/early/2019/01/31/jgs2018-076.full AB - Despite detailed geological studies on the Late Cretaceous Sabzevar ophiolites, the non-ophiolitic, subduction-related igneous rocks of NE Iran are still enigmatic. This paper focuses on the Late Cretaceous, non-ophiolitic Sabzevar magmatic rocks, and presents both precise U–Pb ages and a tectonomagmatic scenario for the genesis of these igneous rocks. A thick sequence of Late Cretaceous acidic volcanic rocks associated with sandstones, shales and pelagic limestones dominates the northern parts of the Lut block. This sequence is intruded by a series of shallow mafic to felsic intrusions. New zircon U–Pb results on the intrusive and extrusive rocks show ages of 75–101 Ma. These ages show a pulsed magmatism in NE Iran, which lasted for c. 25 myr. The whole-rock geochemistry of the igneous rocks shows suprasubduction-zone-related geochemical signatures, represented by negative anomalies in high field strength elements and enrichment in large ion lithophile elements. The initial 87Sr/86Sr ratios and εNd(t) values of the extrusive rocks range from 0.70411 to 0.70628 and from +5.9 to +7.4 respectively, and for intrusive rocks are in the range of 0.70423–0.70579 and +5.8 to +7.2. High εNd(t) values for these rocks confirm that their melts were derived from a depleted-mantle source. Both geochemical and isotopic data indicate that the genesis of these rocks was related to the partial melting of mid-ocean ridge basalt-type slab or depleted-mantle wedge sources during the northward movement of the Sabzevar oceanic slab beneath the southern edge of Eurasia (Turan block) in Late Cretaceous time.