Spatial Arrangement of Fold Types in the Zagros Simply Folded Belt, Iran, Indicated by Landform Morphology and Drainage Pattern Characteristics
Document Type Article
Published in the Journal of Maps (2008): 417-430. Copyright 2008, Journal of Maps. Used by permission. http://www.journalofmaps.com
The spatial arrangement of fold types within the Zagros Simply Folded Belt was analyzed using satellite images, a digital elevation model and a digital drainage network. Distinct fold geometries, principally fault-bend folds and detachment folds, can be identified by characteristic interactions with streams flowing SW from the High Zagros Mountains into the Persian Gulf. In addition, the morphology of the landforms is reflected in the minor channel patterns across the folds. This morphology can also be categorized using geomorphic indices, L/W ratio and symmetry index. The distribution of fold types is shown for the region N27°-N30°, E50°-E54° at a scale of 1:750,000. Anomalously long, high-aspect ratio folds, coincident with topographic steps, were inferred to be fault-bend folds, crossed by multiple wind gaps, overlying major thrust faults. These faults formed sequentially as the deformation front migrated from the collision zone towards the SW, causing diversion of stream channels. Movement up thrust ramps created fault-bend folds behind which serial detachment folding developed in the cover.