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Progressive deformation at a convergent margin (the Zagros Simply Folded Belt) was analysed using satellite images, digital elevation models, contour maps and artificially generated stream networks. Two end-member fold types (fault-bend folds and detachment folds) interact with streams flowing from the High Zagros Mountains into the Persian Gulf. Growing folds divert streams and create wind or water gaps in characteristic patterns which are related to the uplift histories of the two fold types. Additionally, the symmetry of minor channels reflects the inherent symmetry of the folds. The distribution of fold types is shown for the region N27°- N30°, E50°-E54° at a scale of 1:1,000,000. Anomalously long, high-aspect ratio folds, coincident with linear trends of wind gaps and topographic steps, were inferred to be fault-bend folds overlying major thrust faults. These faults formed sequentially as the deformation front migrated from the collision zone to the SW, causing diversion of stream channels. Movement up thrust ramps created these fault-bend folds and serial folding developed in the cover to the NE.