Subduction, high-P metamorphism, and collision fingerprints in South Iran: constraints from zircon U-Pb and mica Rb-Sr geochronology

H. Shafaii Moghadam*, M. Brocker, W. L. Griffin, X.-H. Li, R. X. Chen, S. Y. O'Reilly

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

The Esfandagheh region of the Zagros Orogenic Belt is an ideal area to address many aspects of continental convergence between Arabia and Eurasia, including incorporation of Late Neoproterozoic (Ediacaran) basement, subduction-related magmatism, and the formation of HP/LT rocks. The rock units exposed here represent a presumably Jurassic magmatic arc within the Sanandaj-Sirjan Zone (SSNZ), remnants of oceanic lithosphere, blueschist- and greenschist-facies rocks, and a distinct group of poorly characterized rocks. U-Pb ages define four populations, related to Paleoproterozoic, Ediacaran, Carboniferous, and Jurassic magmatic events. U-Pb ages of approximate to ~1.8-1.7 Ga for a pegmatite represent the first report of Paleoproterozoic rocks in Iran. Zircon U-Pb ages from the SSNZ provide evidence for Ediacaran (547 Ma), Carboniferous (326-312 Ma), and Jurassic (194-186 Ma) magmatic activity. Zircons from the Haji-Abad ophiolites yielded Jurassic ages. The new Rb-Sr results from white micas provide indications of a poorly constrained >85 Ma high-pressure metamorphic history. Rb-Sr ages of two chlorite-epidote-actinolite schists indicate that greenschist-facies P-T conditions had already been attained around 130-125 Ma. The new results are consistent with a model in which the closure of the Esfandagheh Ocean and the subsequent collision between Arabia and Iran led to incorporation of Paleoproterozoic and Cadomian rock units and tectonic juxtaposition of all lithotectonic elements, from oceanic lithosphere to continental crust, along the Main Zagros Suture Zone.

Original languageEnglish
Pages (from-to)306-332
Number of pages27
JournalGeochemistry, Geophysics, Geosystems
Volume18
Issue number1
DOIs
Publication statusPublished - Jan 2017

Keywords

  • Hf isotopes
  • HP/LT metamorphism
  • Rb-Sr geochronology
  • SW Iran
  • U-Pb zircon
  • Zagros

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