ORIGINAL PAPER Pre-Permian uplift and diffuse extensional deformation in the High Zagros Belt (Iran): integration in the geodynamic evolution of the Arabian plate Saeid Tavakoli-Shirazi & Dominique Frizon de Lamotte & Jean-Christophe Wrobel-Daveau & Jean-Claude Ringenbach Received: 3 November 2011 / Accepted: 8 February 2012 # Saudi Society for Geosciences 2012 Abstract The High Zagros Belt includes exposures of Lower Palaeozoic rocks in the core of several thrusted anticlines developed during the Cenozoic Zagros orogeny. The structural style and tectonic evolution of this area during the Palaeozoic remain poorly understood due to the complex- ity of the subsequent deformation. We present the preliminary results of a field study focusing on the structural geology of Palaeozoic rocks in this area. We confirm the existence of an angular unconformity below the Lower Permian Faraghan formation. In the geological literature, this unconformity is reported as the “Hercynian Unconformity” suggesting a rela- tionship with the Hercynian (Variscan) orogeny, which affect- ed Western Europe and westernmost Africa during the Carboniferous. Surprisingly the only observable structures sealed by this unconformity are N to NE trending normal faults and tilted blocks without any evidence of compressional deformation. This pre-Permian extensional deformation, which is general at the scale of the HZB, raises questions about the geodynamic significance of the “Hercynian uncon- formity” in the study area and, more generally, in the Arabian plate. Keywords High Zagros Belt (Iran) . Palaeozoic . Arch . Hercynian unconformity . Normal faulting Introduction Throughout the Arabian plate, a more-or-less significant sedimentary hiatus separates the continental early Permian sequence from the older sedimentary formations (e.g. Konert et al. 2001; Johnson 2008). This hiatus and related unconformity is generally referred to the “Hercynian uncon- formity” (see a recent synthesis by Faqira et al. 2009) suggesting a relationship with the Hercynian (Variscan) orogeny, which affected Western Europe and north-western Africa during the Carboniferous (e.g. Simancas et al. 2009; Michard et al. 2010). Our field work in the central and eastern High Zagros Belt confirms the existence of an an- gular unconformity below the Lower Permian Faraghan formation. Surprisingly the structures sealed by this uncon- formity are normal faults and tilted blocks without any evidence of compressional deformation. This observation, which is general at the scale of the High Zagros Belt, raises the question of the significance of Hercynian unconformity in the study area and, more generally, in the Arabian plate. After a short description of the geology of the High Zagros Belt, we will present field data illustrating both the attitude of the pre-Permian unconformity and the geometry of inherited normal faults and tilted blocks in both the central and eastern High Zagros Belt. We will conclude with a S. Tavakoli-Shirazi : D. Frizon de Lamotte : J.-C. Wrobel-Daveau Department of Géoscience and Environnement, University of Cergy-Pontoise, F95 000 Cergy-Pontoise, France S. Tavakoli-Shirazi (*) Geology Department, NIOC, Exploration Directorate, Seoul Ave,P.O. Box 19395-6669, Tehran, Iran e-mail: saeid.tavakoli@u-cergy.fr D. Frizon de Lamotte TOTAL, Projets Nouveaux, TBF, place Jean Millier, F92 400 Paris-La Défense, France J.-C. Wrobel-Daveau : J.-C. Ringenbach TOTAL, Département d’interprétation structurale et sédimentaire, CSTJF, Av. Larribeau, F64 000 Pau, France Arab J Geosci DOI 10.1007/s12517-012-0542-5