Many curved, large-scale structures can be seen in the eastern Iranian ranges. The Jun-Abad structural curvature is convex towards the southeast, characterized by an arclength about 20 km and an arc width of about 10 km in map view. This synform structure is similar to a half-saucer comprises in numerous thrust sheets of Eocene turbidites, pelagic and basaltic sedimentary sequences of Cretaceous and remnants of ophiolitic mélanges that have totally been undergone low degrees of metamorphism and slaty cleavage. Field surveys and mesoscopic studies indicate considerable displacement of rigid blocks including sandstone to metabasite on the underlying plastic phyllitic shale in an apparently divergent pattern outward of the synform structure. Silica veins with a plastic deformation in the place of thrusts, shear band and related duplex structures confirm this issue. The amount of movement around and inside the synform was noticeable everywhere and it does not decrease towards the center, because the core of the synform is made of an allochthonous klippe of older pelagic sediments. Conjugate faults and boudins of granite blocks represent tangential longitudinal strain around the arc, while the parasitic folds mark the inner arc shrinkage. The mentioned evidence show that the curvature is probably of the orocline type. The synform has occurred simultaneously with the general buckling in the late Paleogene of the eastern Iran. This arcuate structure has developed iron-bearing silica zones, serpentinite peridotites impregnated with copper carbonates, and gold/manganese zones in a half-ring-shaped pattern which is an effective model for future explorations.