Abstract
So far, the settlements of the Iron Age of Sarakhs plain have not been studied archaeologically, and on the other hand, the Iron Age of Plain Sarakhs represents the Yaz culture in the region and owes its name to the Yaz Hill area in southwestern Turkmenistan. Studies of the Iron Age culture of the Sarakhs Plain can reveal the basic information of this period and help to understand the general Iron Age of the Iranian plateau and the land of Turkmenistan. The purpose of this study, while identifying Iron Age settlements, is to analyze environmental factors to explain the patterns of Iron Age settlements in the Sarakhs plain. For this purpose, a field study was conducted in the plain and by studying the collected works and library studies. It was found that 16 sites have Iron Age artifacts. Some settlements are single-period and some have chronological sequences. The necessity of the present study is the unknown culture of the Iron Age of Sarakhs plain. Therefore, the identified Iron Age settlements of Sarakhs plain were analyzed from the perspective of environmental factors and their role in explaining settlement patterns. The output of maps and data of Iron Age settlements in Sarakhs plain showed that among the environmental factors influencing the determination of settlement patterns, Distance and proximity in the range of 300 to 900 meters above sea level, Location of settlements along the rivers of Sarakhs plain (linear settlement pattern) and large urban or rural centers (Mir Ahmad and Bazangan) up to 65 hectares (central location), Communication routes (communication route of Greater Khorasan in the Iron Age), In the formation and distribution of settlements have been more influential than other environmental factors. One of the most important results of the present archaeological study, Identifying the Iron Age settlements represents the culture of Yazd Plain Sarakhs, which will be used to measure the distribution of Iron Age settlements in this area to draw a very accurate and comprehensive perspective for understanding the social life of the people of that period.
Keywords: Archaeology of Northeast Iran, Sarakhs Plain, Iron Age, Yaz, Establishment Patterns.

Introduction
Sarakhs Plain as the research site has been a favorable habitat for the formation of various human communities due to its natural potential and optimal environmental conditions, including altitude, suitable soil and relatively favorable weather conditions. The study of the collected works of the Iron Age in the Sarakhs plain through archaeological investigation shows that some cultural traditions of southwestern Turkmenistan (Yaz culture) of the Iron Age were prevalent in the Sarakhs plain, and this plain is probably the link between the southwest of Turkmenistan and the northeast of Iran and culture. Its pottery is noticeably and significantly influenced by the culture of southwestern Turkmenistan (Yaz area). At the end of the Bronze Age, a new culture covers Central Asia and Southwest Turkmenistan, which is known as the Yaz culture, and it borrows its name from the Yaz Tepe area, located in the southwest of Turkmenistan and present-day Ashgabat. The pottery of this period is generally simple and in red, pea and gray colors.

Materials and Methods
The current research is based on the purpose of fundamental research and based on the nature and method of descriptive and analytical research. The method and tools of data collection in this research have been done in two ways: documentation and field activities. In the field survey, while surveying the plain in the region and identifying the settlements, the required archaeological information and evidence (pottery) were collected from the said sites and recorded in the database. In order to obtain scientific answers, the conventional methods of establishment patterns and GIS and Spss analyzes were used in this research, and after preparing the outputs and maps, two descriptive and inferential methods were used to analyze the questions.

Data
Our information about the land of Turkmenistan is based on the findings of Russian and Turkmen archaeologists’ excavations in the region and presenting their latest findings and reports, some of which have been translated and used, which can be used as library studies. he remembered at this stage, all written sources, images and maps were collected and analyzed. In the field investigation, while surveying the plain in the region and identifying the settlements, the required archaeological information and evidence (pottery) were collected from the mentioned areas and recorded in the database.

Discussion
At the end of the Bronze Age, a new culture covers Central Asia and Southwest Turkmenistan, which is known as the Yaz culture, and it borrows its name from the Yaz Tepe area, located in the southwest of Turkmenistan and present-day Ashgabat. The iron settlement patterns of the Ferns Plain have been formed with the influence of these environmental and natural factors. With these interpretations and based on this, in the current research, the relationship of each establishment and establishment patterns with respect to major and main environmental variables have been analyzed and measured.

Conclusion
During one season of archeology field investigation in Sarakhs Plain and study of collected works and library studies, it was obtained that the extent and continuity of culture in the place, the proximity and location of the settlements along the Tajan, Harirood, Kashafrood, Shurluq and Chakoodar (linear settlement model) in all the geographical directions studied in Sarakhs Plain showed that This plain has a direct relationship with the facilities and environmental conditions, such as the quantity and quality of settlements, the frequency and increase of the Iron Age settlements of the Sarakhs Plain compared to the previous period in terms of population density and the gradual complexity of the relationships between settlements and the relationship with the environment and Direct exploitation of water resources for agriculture and animal husbandry has been on the rise and in the last period of the Iron Age It increased all of a sudden and it is through this plain that this culture spread to other areas of South Khorasan and the plateau of Iran. In order to analyze and explain the settlement patterns of the Iron Age of Sarakhs Plain, a test was conducted between various ecological variables with the distribution of settlements based on the Pearson correlation coefficient and the effect of the significant level. The result of this study was the identification of 16 settlements from the Iron Age, which can be considered and evaluated from the perspective of environmental factors and the size of the sites. In the analysis and explanation of the Iron Age settlements in the Sarakhs Plain, the height above the surface of open water, the distance from rivers and other water sources, and the distance from communication routes with Pearson’s correlation coefficient with a significant level, had the greatest impact, and the other variables each implied They have left a significant impact on the Iron Age settlements of the Ferns plain. The results of Pearson’s correlation coefficient indicate that the distribution of Iron Age settlements in the Sarakhs Plain are regularized in relation to environmental and ecological capabilities and limitations, and these factors have played a significant role in the spatial distribution, determining the type of function and the importance of Iron Age settlements in the Sarakhs Plain. This has had an undeniable effect on the distribution of the population, the type of livelihood, the settlement patterns and their bodies. The Iron Age settlements that can be seen in this plain are the result of the specific geographical conditions of the region.