The study of the role of Quaternary tectonic and climatic factors on the geomorphological evolution of Meshkin Shahr depression fan systems

Aims & Backgrounds: The Quaternary period is considered as the interval of climatic oscillations (glacial and interglacial) coupled with tectonic episodes. Therefore, tectonics and climate have simultaneously governed the evolution of Quaternary alluvial fans. Unraveling the tectonic and climatic factors under varied depositional systems is therefore the fundamental issue in understanding the evolution of Quaternary fans. Quaternary alluvial fans of Meshkin Shahr depression, in northwest Iran and northern slopes of Sabalan are no exception. The present study aims to the investigation of the role of tectonic and climatic factors of the Quaternary period on the geomorphological evolution of fans system of Meshkin Shahr depression. Such a study could be involved in spatial planning. Methodology: To achieve this goal, First of all, using contour line, stream network and elevation points, the Digital Elevation Model was prepared as a base map in GIS.  Then the data needed to calculate geomorphic indices (river concavity, the semi-logarithmic profiles of the rivers and incision of the alluvial fans), drawings of maps (topography and river networks) and various profiles, were extracted. Geological logs are used to investigate sedimentary evidence. In addition, Arc Hydrow and Google Earth have been used to outlined and identified catchments and fans area. Most importantly, we have used extensively field observations most of all. Conclusion: The results of this study showed that tectonic activity and climatic changes of the Quaternary have played a decisive role in the formation and development of Meshkin Shahr depression fans system. Sabalan volcanically activity coupled with the rule of the glacial period or torrential rainfall in the Late Pleistocene era caused a mudflow (Lahar) periodically and deposits on the alluvial fans. In contrast, climatic conditions changes from the glacial period to the interglacial during the Holocene have caused the incision of the fan and basin systems.