Landsat Thematic Mapper (TM) images of eastern Zagros ranges, Iran, were evaluated for information about the bedrock geology and primary Neogene structures. Digitally processed TM subscenes have been compared with regional tectonic elements. Analysis of these images suggests that the regional geology in the area immediately east of the Zagros fold belt is characterized by thick volcanic piles which were emplaced during several episodes. On the images, these volcanic rocks depict a wide range of colours which correspond to their relative age differences from Jurassic rhyolitic and dacitic lavas to Tertiary tuffs. The Cretaceous-Paleocene carbonate and coloured melanges along with Jurassic volcanics appear to have undergone intensive compressive deformation indicated by the intermingled spectral reflectances of the rocks. Mappable features within the deformed sequence show a persistent N-S structural grain overprinted by a NW-trending fault trace. In the south-east portion of the area two sets of dike swarms dissect the older volcanic rocks. A prominent N-S-trending, steeply eastward-dipping set is truncated and dextrally oMset by faults associated with the north-westerly set. This suggests that the post-collisional tectonic pattern in the area is dominated by an element of dextral transpressional shear.