بررسی الگوهای استقراری عصر مس‌وسنگ و مفرغ در منطقه‌ی سرایان، خراسان جنوبی

Sarayan region is one of the most studied areas of South Khorasan Archaeology in recent years which has not been many studies. This area comprises two parts from landscape: mountainous and plain. These parts have provided environmentally favorable locations for settlements formation in past. As the formation of early settlements have always been dependent to environmental factors. one of these approaches in archeological studies is the study of the settlement pattern and analysis investigating the formation process of archeological sites in environmental contexts. It seems human interactions with the environment in the South Plain of Sarayan causing a distinct landscape. Information and awareness of settlement pattern of area could improve the perception of its cultural landscapes. In the past, this kind of analysis was done through traditional methods but nowadays analysis of settlement pattern is done by different software like ArcGIS that results in real and accurate information. The present study investigates 16 settlements of the Chalcolithic and Bronze ages in Sarayan region that were identified in archaeological survey of Sarayan. This research studies the settlement pattern recognition of the pre-historic period in this region for the first time. The most important questions are how settlements are formed in the region and factors affecting settlements formation during the Chalcolithic and Bronze ages. Therefore, first, were performed typological comparison of the data and the settlements chronological then, GIS software was used to analyze and identify settlement patterns of Sarayan area with various factors of natural and human geography. Accordingly, various variables were analyzed such as precipitation, rivers and environmental contexts. These analyzes showed that different variables have an important influence on the settlements formation. These variables include elevation code, temperature status, access to permanent water sources. Even the number of sites have been created on the border of permanent rivers in this region.
Keywords: Settlement Patterns, Chalcolithic Period, Bronze Age, Archaeological Survey, Sarayan.
 
Introduction
The interaction between human and her surrounding environment creates cultural landscapes in nature. It is a reciprocal relationship. The environment forms the basis of culture by its capabilities and limitations and cultures adapt to the environment by using environmental features and overcome environmental constraints and lead to the formation of landscape in environmental contexts. Influence of human on the natural environment has always provided a spatial distinction in terms of population and habitat density and it has caused the formation of specific patterns of habitation in different ancient periods. The interaction in between human and environment is important in settlement pattern discussion, as human and environmental conditions have influenced each other in a same place; In other words, human has changed the environment to his advantage as much as affected by the environmental factors. This effect has made some changes in the environment and human behavior. What we know as culture –the human distinctive feature- is the result of this adaptation and behavior basically. The interaction between human being and environment either in the form of human effect on the environment or the environment effect on the human, cannot be considered out of the environment.
Khorasan province which is located among the cultural area of southwestern central Asia, northeastern of central plateau and northeastern Iran is one of the unexplored but important regions in archaeological investigation in Iran. Sarayan region is one of the most studied areas of South Khorasan archaeology in recent years which has not been many studies. Sarayan region is located in North West South Khorasan relatively cool climate and the mountain. Plains and mountains around the Sarayan have been quite capable of living in different moments of human life. Surveys accomplished in this area show that happened the peak of progress and cultural development in the fourth and third millennium BC.
Research Questions: The most important questions are how settlements are formed in the region and factors affecting settlements formation during the Chalcolithic and Bronze ages.
Research Hypotheses: These analyzes showed that different variables have an important influence on the settlements formation. These variables include elevation code, temperature status, access to permanent water sources. Even the number of sites have been created on the border of permanent rivers.
Research Method: The method of collecting data are field and libraries. Therefore, first, were performed typological comparison of the data and the settlements chornological then, GIS software was used to analyze and identify settlement patterns of Sarayan area with various factors of natural and human geography.
 
Discussion
Archaeological survey of central district of Sarayan started in 2011. In this study were discovered different sites from pre-historic to contemporary period. Most of these sites are related from the 4th to 2th millennium BC. Generally, the distribution of these settlements is due to geographical and human factors. In fact, geography has been influenced in all stages of life of human societies. Another factor is the human factor. In fact, the purpose of the human factor is both nomadic and sedentary societies who live more close to each other.
Of total identified settlements in the Sarayan rgion, only 3 sites have been created in mountainous areas and 13 sites in the southern plain of Sarayan. It seems that there are more sites in this plain but they have been buried under the sands over time due to the abundance of sand and heavy winds. However, it is difficult to identify ancient settlements in mountainous areas due to specific topographical conditions and impassable mountains. Undoubtedly, these settlements continue in the northern half of 3Qale district,that needs a systematic survey to obtain a comprehensive scale of the prehistoric sites and their location in the region. In general, of all the identified settlements in this survey, pre-historic settlements inclusive for about 11% of the total identified settlements of the central district.
The samples of pottery collected from the surface of prehistoric settlements are the most of the data related to this period in this region that used for typology and chronology. The results of these studies show the many similarities of the Sarayan pottery traditions with the central plateau, northeast of Iran, southeast of Iran, Pakistan and Afghanistan regions. The typological results of these sites show that these sites are from the 5^th to 2^th millennium BC.
Conclusion
The results of the present study show that except for 3 sites including Nodeh, Zou, and tappeh Pas-e- Borj, the other settlements are located in the southern part of Sarayan and in one settlement line. So that all sites are located in the southern plain and southern jungle or on the farmlands. Sandy bedding and strong winds have buried most of these sites under the soil, and this is a potential threat to these sites that may remain unknown or destroyed.
Statistics show that 80% of the settlements are formed in lowly and sandy plains with very low slope and only 20% of settlements are formed in higher and sub montane areas. It should be known that this model has been tested based on surface surveys and for this reason, it may not be able to cover some sites and settlements. As mentioned, it may many sites have been covered by sedimentation and sandstorms. It is also possible some of the sites within the Jungle and the Southern Plains of Sarayan in the pre-historic times have been created to temporary settlement. Because this nomadic life was prevalent in this region in Islamic period. Ethno-archeology models can help us in this context.