Investigating the Role of Faults in the Morphology of the Northern Plains of Zanjanrood

One of the unique features of the northern plains of the Zanjanrood water basin in Zanjan province is the existence of parallel rivers to the deep valleys. Given the gentle slope of smooth surfaces around the valleys, which do not end up in the valleys, it can be said that the existing landforms are not in equilibrium with today's processes. The distinction between mountain conics in topographic maps and field evidence suggests that new plains are not expanding in the plains, while the valleys are excavated within the old alluvial fans and the entire surface of the northern plains are covered. The rivers such as Sohrien, Armaghankhneh, and Saromsaghloo, which have a considerable water surface area above the mountain-front sinuosity, are in deep valleys, which in their mountainous sinuosity, sometimes their depths exceed 100 meters and in the long run a large part of the route ends with the maintenance of the initial altitude difference relative to the surrounding areas to Zanjanrood. A survey of topographic conditions of the alluvial-covered plains, the pattern of parallel streams and the closure of the plains of the deep-water valleys from the topographic and geological maps of the area, along with field evidence, indicate intense tectonic involvement in evolution of the northern plains of Zanjanrood. In this research, morpho-tectonic indices such as the river length gradient (SL), asymmetry factor of catchment (AF), the valley floor width- to- height ratio (VF), mountain-front sinuosity index (SMF), and Symmetry of lateral topography (T) have been used. Estimated numbers in terms of the above indicators were classified in three classes from 1 to 3 (active or inactive). The results indicated that this sub-area is tectonic and in the active group.
channels.