Paleogeomorphology of successive dam lakes and its effects on the civilization in Saymarreh region

Saymarreh landslide, as the largest landslide in the world, has resulted in the formation of successive dam lakes in the several stages in the late quaternary. The distribution of archaeological sites on sediments deposited in these lakes, geomorphological and geoarchaeological evidence show a significant relationship between the development of civilization and paleogemorphological events of the region. The purpose of this research is to determine and analyze the relationship between the development and decline of civilization with the Paleogeomorphology and paleoenvironmental changes. The research method is experimental based on the field and laboratory data. Field studies were carried out on the lakes sediments, excavation of trenches and location-selection of human habitats. In order to determine the formation time of the lakes and its definitive effects on the civilization, the two trenches were excavated within the ancient sites, then stratigraphy of the trenches was determined and a sampling was done. Several samples were analyzed, and four of them were dated by OSL dating method. The results of field and laboratory studies indicate that the several successive lakes had been formed after the Saymarreh landslide occurrence in the region, and the late quaternary especially the Holocene epoch can be divided into lake and inter-lake periods. The three lake periods (6460, 3110, and 570 years ago, respectively) coincided with the historical periods of human habitation and the development of civilization in the region. The development of civilization and the increase of human settlements coincided with the inter-lake periods, and the decline of civilization, the destruction of human settlements and cultural transfer coincided with the lake periods. Changes and fluctuations in the human habitation trends in the region had been influenced by the lake periods and, conversely, these changes prove the occurrence of lake periods during the Holocene. Generally, the formation of successive lake periods as a geomorphic factor played the most important role in the development and decline of civilization in the Saymarreh region during the Holocene.