Late Cretaceous to present protracted convergence between Arabia and Iran

The Zagros orogeny took place during a protracted period of time, and its complete evolution is difficult to ascertain due to the multiple stages starting with oceanic obduction related processes and culminating with arc-continent and continent-continent collision. We document the geometries and ages of the Zagros foreland basin with a large number of dated samples along 16 stratigraphic successions, and hinterland denudation history with AFT ages on both bedrock and detrital samples. We integrate these data together with a crustal cross-section across the Lurestan region to constrain the total shortening amounts using extrapolations of rates of shortening as well as crustal reconstructions based on area balance from the Late Cretaceous times to present. The orogenic history of the Zagros is much longer and shortening probably much higher. The crustal area balance assuming shallow marine deposition at the onset of flexural basin formation could form with crustal thicknesses of about 27 km in the NW Arabian margin. Comparing to present day thickness of the crust underneath the internal Zagros Mountain presupposes a crustal shortening of about 150 km. This amount fits well will independent extrapolations of rates of shortening calculated in the Late Cretaceous-Eocene foreland basin in Lurestan.