تحقيقات جغرافيايی (Apr 2019)
Role of Quaternary Tectonic and Climatic Factors on the Geomorphological Changes of Meshkin Shahr Depression Alluvial Fans
Abstract
Aims & Backgrounds: Based on field and literature studies, one of the most important features of Sabalan Quaternary landscape, are climate changes and tectonic activities. So tectonic activities and climate changes, along with other internal and external factors simultaneously had an undeniable role in the formation and evolution of Quaternary fans of Meshkin Shahr depression. The purpose of this study was to investigate the role of tectonic and climatic factors of quaternary period in geomorphological evolution of Meshkin Shahr fans. Methodology: To achieve this goal, first of all, using contour line, stream network and elevation points, the digital elevation model of region, was prepared as a base map. Then the data needed to calculate geomorphic indices and various profiles were extracted. Geological logs are used to investigate sedimentary evidence. In addition, Arc hydro and Google earth have been used to outline catchments and fans area. In addition, to draw geological logs, Rock works 16 software was used. Most importantly, we have used extensively field observations. Findings: The two major phenomena of volcanic-tectonic and climate changes in the Quaternary period have played a decisive role in the formation and development of the Quaternary fans of Meshkin Shahr depression. Simultaneously, the Sabalan volcanic activity with glacial dominate or tundra storm during the late Pleistocene led to the formation of a mudflow periodically and sedimentation in fans and basins. In contrast, climate change from glacial period to interglacial during the Holocene and tectonic relaxation has caused the incision of basins and fans. Conclusion: Sabalanchr('39')s landscape as the main controller of Meshkin Shahr Depression Fans is at a transitional stage, which means that it has undergone a tectonic stage to a non-tectonic stage, and also, it has undergone a glacial to an interglacial period such as the present conditions.
