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The Zagros Mountains of Iran formed by continental collision from closure of the Neo-Tethyan Ocean. The Zagros Orogen underlying the mountain range reflects a much longer history with the Pan-African basement and Phanerozoic successions. New mapping, radiometric ages, and stratigraphic analyses have enabled advances in our understanding of the Jurassic to Cenozoic tectonic history. The northwestern Zagros Orogen consists of three belts: (1) the Zagros Fold and Thrust Belt, divided into the outer Zagros Simply Folded Belt and the inner High Zagros Belt; (2) the Zagros Suture Zone including radiolarite, ophiolite, and Bisotun limestone thrust sheets; and (3) the Sanandaj–Sirjan Zone, which contains abundant metamorphic rocks. Late Cretaceous ophiolites of the Kermanshah region are part of the outer ophiolite belt of the Zagros Orogen and have formed in passive margin and supra-subduction zone settings. Major events include early Mesozoic rifting, Jurassic subduction followed by a more cryptic interval of subduction in the Cretaceous, multiple ophiolite emplacement on the Arabian margin in the Late Cretaceous to Eocene, and collision of central Iran and the Arabian margin in the Oligocene with final closure of the shallow Tethyan seaway in the mid-Miocene. A Middle to Late Jurassic plutonic belt, the Qorveh–Aligodarz Plutonic Belt, formed a magmatic arc with subdued topography related to a moderately NE-dipping subduction zone under the Sanandaj–Sirjan Zone. An Early Cretaceous unconformity reflects limited uplift followed by widespread marine deposition with intercalated volcanic rocks in the Sanandaj region. Subduction continued with a low-lying arc that underwent trenchward advance. In the Late Cretaceous to Oligocene interval, the Neo-Tethyan Ocean closed with ophiolite obduction over the Arabian Peninsula margin and major shortening affected the Sanandaj–Sirjan Zone with uplift and plutonism. Much of the forearc of the Jurassic to Cretaceous arc system has been lost by tectonic erosion along a low-angle Eocene subduction zone prior to collision. Flattening of the subducting slab in the Late Cretaceous and Palaeogene explains the inland retreat of the arc to central Iran. Continental collision initiated in the Oligocene but the Tethyan seaway remained open until the mid-Miocene. [ABSTRACT FROM PUBLISHER]

The Laibid pop-up structure is located in the highly deformed sub-zone of the Sanandaj-Sirjan Zone, western Iran. In this zone, structural trends are parallel to the Zagros fold-thrust belt (NW-SE), but the pop-up structure has a different trend of E-W and is surrounded by several fault sets, which are the youngest deformational event. Comparison between the fold axes and axial plains of the inner and outer part of the pop-up structure and also coaxial interference patterns of polyfolding show a continuous deformation in the study area. It seems that during Late Jurassic, due to right lateral transpression movement resulting from the collision of the Iranian and the Afro-Arabian continents, three folding stages formed and passively rotated in a continuous deformation condition. [ABSTRACT FROM AUTHOR]

Abstract: Kilometre-scale subparallel folds in the NW–SE trending Shahdad fold-and-thrust belt show active thin-skinned deformation produced by late Pliocene–Quaternary compressional tectonics between the Yazd and Lut blocks of the central microcontinent of southeast Iran. The Shahdad fold-and-thrust belt developed in a Miocene–Quaternary sedimentary sequence with gypsiferous marl overlain by well-stratified gypsiferous siltstone, sandstone, and conglomerate. The geometry of the fold-and-thrust belt is shown in four regional cross sections, which demonstrate common fault-propagation folds developed above thrusts splays and associated with curving ridges. In the northeast, incipient thrusts and back thrusts have developed at the tip of the blind northeast-dying-out sole thrust. However, further west, a major back thrust has brought to the surface the lower part of the stratigraphic succession (Malakhordeh thrust). In some fault-related folds, parts of the folds have been eroded and syntectonic sedimentary strata containing younger gypsiferous conglomerates have been deposited over an unconformity surface. These younger layers are also flexed above the underlying fault-propagation fold as the result of renewed slippage along the active fault. Collapsing has developed in the hinge zones of these folds. The sole detachment fault has developed through the lower plastic gypsiferous marls near their contact with the underlying Paleocene–Eocene volcanic rocks of the Lut block. [Copyright &y& Elsevier]