Abstract
Sarakhs plain is located in northeastern Iran and adjacent to Turkmenistan. Regarding Parthian pottery studies in Sarakhs plain, no special components have been considered for it so far. Identification and classification of Parthian pottery in this region can be a good tool to better understand the pottery traditions, study the cultural and economic interactions of the population centers of that period. The research method is based on library and field studies (descriptive and analytical) during a field survey (survey) stage. Based on the surface findings of the field survey, a total of 91 flagship pottery pieces from 14 settlements belonging to the Parthian period were selected for the survey. In fact, this study seeks to answer the question of what were the intra-regional and extra-regional relations of Sarakhs plain during the Parthian period with contemporaries? According to the studies on pottery attributed to the Parthian period in Sarakhs plain, this period can be divided into two periods in the mentioned plain. In the first period (formation of Parthian rule before the reign of Mehrdad I) Sarakhs is influenced by the culture of the Sarakhs oasis of Turkmenistan, and in the second period, until the end of the Parthian period, they are influenced by the well-known cultures of southern Turkmenistan, namely the cultures of Nessa and Merv. The purpose of this study is to identify and introduce Parthian pottery in Sarakhs plain, classification and typology of Parthian pottery in the region. The necessity of the present study is that the pottery cultures of the Parthian settlement of Sarakhs plain are unknown and the present study can provide a better understanding for further research.
Keywords: Archaeology of Northeast Iran, Sarakhs Plain, Parthian Period, Classification of Pottery.

Introduction
Sarakhs plain as a study point due to its natural potentials and optimal environmental conditions such as altitudes, suitable soil and relatively favorable weather conditions, has been a desirable habitat for the formation of various human communities (Ebrahimi, 1384: 2). Scholars in historical texts have stated the origin of the Parthians in northeastern Iran, especially Khorasan (Asak near present-day Quchan) and their primary capital was Nessa in Turkmenistan (Altheim, 2010: 20). Based on the field surface findings, a total of 91 flagship pottery pieces from 14 settlements belonging to the Parthian period were examined. The method of this research is based on library and field studies (descriptive and analytical) during a field survey (survey) chapter. Documentation of human handicrafts is necessary in terms of studying the background and type of community culture at any point in history.      
Research Questions and Hypotheses: In fact, this study seeks to answer the question of what were the intra-regional and extra regional relations of Sarakhs plain during the Parthian period with contemporaneous areas? Therefore, in the present study, surface cultural materials have been interpreted by preparing a statistically citation able and scientific population through archeological study. Analyzes obtained from classification, typology and methodological analysis of this statistical population as well as comparative comparison of pottery species with similar examples of contemporaneous settlements show the formation of sequences of some settlements in the Parthian period and continuous continuity before and after the Parthian period in this Has an area.                                                                                                    
Aims of Research: The purpose of this study is to identify and introduce Parthian pottery in Sarakhs plain, classification and typology of Parthian pottery in the region.                                                       

Materials and Methods
The present research is based on the purpose of basic research and based on the nature and method of descriptive-analytical research. The basis of the research is the study of Parthian pottery along with library studies. Methods and tools of data collection in this research have been done in two ways: documentation and field activities. In the documentary stage, all written sources, images and maps were first collected and analyzed. In field studies, while surveying the plains 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. In order to compare the chronology of the settlements and analyze the pottery of the Parthian settlements, the total pottery collected from 14 Parthian sites was examined and compared with other sites of the Parthian period such as Nessa, Merv and Sarakhs oasis of Turkmenistan. It was not possible to identify more Parthian sites through surface surveys. 91 index pottery were selected for photography, design, classification, typology and comparison with other Parthian sites. The index samples were selected as research materials based on classification and typology. In archeology, when classifying, the differences and similarities of the pottery in question must be clearly evident in the various groups that are distinguished; In such a way that no further explanation is needed for easy identification of one group from another. It is logical to expect that no two groups of objects classified in the main and important criteria are common to each other (Azarnoosh 1377: 76). In the present study, first, in a general division, pottery pieces are divided into five general categories, including: 1- edge 2- body 3- floor 4- base 5- handle, and then edge pieces that can be recognized in the form of a container. 

Discussion and Results  
In this study, 91 Parthian pottery pieces were identified from 14 ancient settlements related to the Parthian period, many of which have chronological sequences and in addition to the works of the Parthian period, also have the works of other periods. Settlements were classified based on pottery typology, comparative studies of pottery find, and archaeological excavations in southern Turkmenistan, northeastern Iran, eastern Iran, Pakistan, Afghanistan, and other regions within and outside the region. A total of 26 sites in 11 areas for this study in the order in which it is presented has the most references. Based on this, a table was designed for each cultural region and settlements of each basin in which the amount and percentage of comparison is clearly significant (Table 2).     

Conclusion
Archaeological study of Sarakhs plain and 91 surface pottery pieces from 14 Parthian settlements were considered as the main foundation for relative chronology, classification and typology of the research. In order to obtain a scientific answer to show the cultural interactions, the method of comparative analysis was used and the findings of the archaeological study of Sarakhs plain were compared with the findings of intra-regional and extra-regional contemporaneous areas. These similarities, taxonomy, morphology, typology, and cultural connections were evident and analyzed. What results from the study of Parthian pottery findings obtained from the Sarakhs plain; According to the studies carried out on pottery attributed to the Parthian period in Sarakhs plain, this period can be divided into two periods in the mentioned plain, in the first period (formation of the Parthian government before The accession of Mehrdad I) to the Sarakhs plain is influenced by the Sarakhs oasis culture of Turkmenistan, and in the second period, until the end of the Parthian period, they are influenced by the well-known cultures of southern Turkmenistan, namely the cultures of Nessa and Merv. The presence of these pottery indicates a two-way and dynamic relationship.    

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.