U–Pb dating and emplacement history of granitoid plutons in the northern Sanandaj–Sirjan Zone, Iran

The Sanandaj–Sirjan Zone (SSZ), which runs parallel to the Zagros fold and thrust belt of Iran, underwent a multistage evolution starting with Neotethys initiation, its subsequent subduction below the Iranian continental crust, and eventual closure during convergence of Arabia towards central Iran. Plutonic complexes are well developed in the northern part of the SSZ and we have dated a number of them by ID-TIMS U–Pb on zircon. The new data record the following events: a Mid Jurassic period that formed the Boroujerd Plutonic Complex (169 Ma), the Astaneh Pluton (168 Ma) and the Alvand Pluton (165 Ma); Late Jurassic emplacement of the Gorveh Pluton (157–149 Ma); Mid Cretaceous (109 Ma) formation of a I-type phase in the Hasan Salary Pluton near Saqqez, followed by Early Paleocene (60 Ma) intrusion of A-type granite in the same pluton; and the youngest intrusive event recorded so far in the SSZ with the intrusion of granite in the Gosheh–Tavandasht Complex near Boroujerd at 34.9 Ma. These different events reflect specific stages of subduction-related magmatism prior to the eventual Miocene collision between the two continental blocks.

► We report ID-TIMS U–Pb zircon ages for plutons in the Sanandaj–Sirjan Zone of Iran.
► Mid Jurassic activity was prominent in the Boroujerd, Astaneh and Alvand complexes.
► Other magmatic episodes are recorded at various sites at 150, 110, 60 and 35 Ma.
► The extended activity reflects subduction of the Arabian plate below central Iran.