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چکیده
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Abstract The study area is northwest part of Sanandaj–Sirjan or Esfandegha–Marivan zone in the northwest of Iran. The oldest rocks which are limestone, sandstone, tuff, and lava belong to the Jurassic which have deformed during the Late Cimmerian orogeny. This complex is unconformably overlain by Cretaceous volcano sedimentary. The dominantly Cretaceous outcrops are limestone, shale, tuff, and basic to intermediate volcanic rocks. The Jurassic complex was locally metamorphosed by granitoid intrusions during the Cretaceous. Geochemical interpretations show some differences in magmatic activity in the Jurassic and Cretaceous periods. Furthermore, the chemical composition confirms the alkaline to calc alkaline trend for these two major groups. In petro-tectonic diagrams, they plot in the extensional and active margin tectonic regime. The existence of a few hundred meters of Jurassic lava with interbeded sediments, which have deformed in the Late Cimmerian orogeny infer the simultaneous existence of extension and subsidence during the Jurassic and so a compression regime in the late Jurassic (Late Cimmerian). Based on our findings, this area shows sporadically occurring extension and compression tectonic regimes over the subduction zone in the Jurassic and Cretaceous such as Cordilleran belt.
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