Settlement patterns and distribution of Iron Age sites in the Middle Atrak Basin

Under the influence of space-making factors and forces, human settlements have always been changing and evolving by influence of various internal and external processes. In the meanwhile, human settlements, as a part of geographical systems, which themselves are composed of related components, affected by their spatial location, have been interacted with or related to the environment. Among them, the role of environmental-natural factors is very prominent in the spatial organization of human settlements; Because the formation, continuation or abandonment of settlements is based on the use of water and soil resources and sometimes their durability and stability is in the presence or absence of natural resources. Environmental and natural contexts provide the necessary conditions for the establishment of human settlements, but some of them have more stable conditions than other factors. These parameters are slope, altitude, water resources, soil and land potential. The present study is a descriptive-analytical one that investigates the settlement patterns and distribution of Iron Age sites in the Middle Atrak basin. In order to achieve the research objectives, 6 natural factors including the site area, altitude, slope, of the site distances from water sources, communication routes, type of vegetation and soil have been selected as effective factors in establishing settlements and have been analyzed using statistical methods in GIS and SPSS software. Investigation of Pearson correlation coefficient on the area of sites with altitude factor is 0/480 and the type of soil where the sites are located is 0/490. These two figures are strong and positive and indicate a high relationship between the site area and these two factors. Relationship between the site areas with the distance from permanent water sources, communication paths and slop, the Pearson correlation coefficient is 0/830, 0/880 and 0/810 respectively. This figure shows the relationship of high, strong and inverse level of significance between area and water resources, land slope and communication path. Pearson correlation coefficient shows that the relationship between the area of the sites and vegetation is 0/389. This figure shows the average relationship. It seems that natural settings have had a great impact on the location, expansion and physical development of Iron Age settlements and the sites of this period have been formed in two parts of sedimentary plain and mountainous region. So that the Iron Age people have chosen a different patterns of living and settlement to adapt to the environment of the Atrak river basin. A very large group of sites is ones that have good access to pastures on the edge of the plain, are located on high slopes and have a small area, indicating that seasonal sites with dryland farming and livestock subsistence economy. The second group is three sites located on low slopes, at the bottom of the plain with rich sedimentary soils, next to communication routes and water sources, and their area is much larger than the first group and show that permanent villages with livestock and agriculture are. Finally, the third group is a site that is the largest area in the region and its location in a strategic area and on the communication route, which controls two plains and the possibility of a central area such as the city, is not far from the mind.