Abstract
In this article, the production systems of lithic artifacts during the Neolithic period of eastern Mazandaran has been studied based on the 2020 excavation of Touq Tepe using a descriptive-analytical approach. Examining the technology, typology, and the effect of subsistence on applying methods of technologies and studying the production methods of various artifacts were among this research project’s most important questions and aims. Touq Tepe is located in the central district of Neka, near Hotukosh mountains, one of Iran’s most important Chert sources. These artifacts were not locally made at the site and part of the production sequence took place elsewhere. Since there was no blade core in the assemblage, it seems that the blades came to the site in already-prepared form and mostly retouching and finalizing processes of the debitages were done at the site. Evidence such as a large striking platform, dual striking bulb, and dented striking bulb indicates that the technology used in the Touq Tepe lithic artifact was either direct percussion with a soft hammer or indirect percussion. Some of the most important characteristics of the assemblage are the abundance of over-flake and notched-denticulated tools and the shortage of scrapers (thumbnail and geometric) and tools with sickle gloss. The lithic industry of Touq Tepe resembles the Mesolithic stone industry of Komishan Cave regarding its technological composition. The production method of the stone artifacts in the Neolithic was likely a continuum of the Caspian Mesolithic period. The subsistence economy has a direct effect on the production method of artifacts. Our study showed that due to the high environmental capacity of the studied area in providing prehistoric societies with food, there was no dramatic change in the typology and technology of lithic tools on the site despite the change of the subsistence towards food production. 
Keywords: Eastern Plains of Mazandaran, Touq Tepe, Neolithic, Developments in Technology and Subsistence, Lithic Artifacts.

Introduction
In the process of Neolithization, and then during the Neolithic period, the hunter-gatherer subsistence transformed into domesticate-farming (Bar-Yosef & Meadow, 1995; Barker, 2006; Hole, 1984; Bar-Yosef & Belfer-Cohen, 1992). With those mentioned transformations came a metamorphosis in lithic tools technology. Thus, technological and subsistence developments are two fundamental issues in Neolithic research.  
Proper archaeological research has shown western and southwestern parts of the Iranian plateau as one of the major zones of Neolithization. Thus, these regions have absorbed most of the research interests regarding the Neolithic period (Roustaei, 2014). Meanwhile, most of the reports on eastern Mazandaran are about Mesolithic sites as far as there is little known about this period even in sites with in situ Neolithic layers like Kamarband (Belt) Cave (Jayez, 2012: 284). Therefore, one of the important aims of this article is to deal with this period through new archaeological findings in Touq Tepe, a site located in Neka Plain, and study the technology and typology of its lithic artifacts.
The current research has studied the technology and typology of stone artifacts from the Neolithic layers of Touq Tepe and the subsistence of its inhabitants, which is useful to clarify the processes of change in the technology and typology of artifacts from the Mesolithic to the Neolithic period and open the way for future studies. Given the proximity of the site to one of the largest and finest Chert sources in Iran, the artifacts were studied for their raw material so a logical relationship between raw material abundance and the diversity of lithic artifacts could be established. Naturally, larger and thicker tools were used for rougher tasks. The production methods of these artifacts were mostly direct and indirect percussion. 
In this study, newly-found lithic artifacts from Neolithic layers of Touq Tepe were first studied separately for classification, typology, sourcing, and investigation of the Neolithic subsistence economy. The findings were classified into four types: tools, debitages, cores, and natural stones. Eventually, the results were compared to published data of the nearby sites from quantity and diversity points of view to establish a foundation for general knowledge about subsistence in the Neolithic period. 

Disccussion
Totally, 348 stone artifacts were recovered from Neolithic layers of Toq Tepe. This assemblage has 6 cores (1.72%) including 3 flake cores, 2 microblade single-side cores, and 1 irregular mixed core. A total of 259 (74.43%) artifacts are simple debitages including 135 flakes, 43 blades, 15 microblades, 2 burin spalls, 35 chips, and 27 debris. 81 (23.28%) tools consist of retouched (31 retouched flakes, 24 retouched blades, and 10 retouched microblades), notched tools, notched-denticulate tools, backed microblades and multi-functional tools and 2 (0.57%) naturally occurred stones. 
The places of flake and microblade on cores are highly irregular and their exterior angles are less than 90 degrees. The blades and microblades have mostly irregular ridges and a profile with low curvature. The ventral surfaces are not completely flat and have waves on them. The thickness of the striking platform in blades and microblades is quite low and flakes with a thick striking platform and prominent striking bulb with dents over the bulb are also rare. In this assemblage, dented striking bulbs are more common in flakes, blades, and finally microblades, but completely absent in burins. 
The flakes were rarely made using direct percussion and in the majority of cases they were produced using direct percussion with a soft hammer or indirect percussion. All the blades were made using direct percussion with a soft hammer or indirect percussion. In microblades, considering the faded striking bulb and their paralleled edges, it is probable that the pressure technique was used Although no pressure microblade core was found. All the lithic artifacts of Touq Tepe were made out of Chert with various color spectrums but mostly from light to dark brown. 

Conclusion
The number of simple debitages is far more than debitages turned into tools and those that turned into tools have larger dimensions and irregular retouches. Based on the comparison of the average sizes of the tools made over the flake blank and the simple debitages on the flake blank and the high ratio of chips to the tools, it can be concluded that the process of making and converting simple debitages to tools was taken place in the site and according to the immediate needs thus most of the retouches are irregular. Scrapers were mostly made over flake blanks and have denticulate or notched-denticulate retouches that do not need any special pre-design. 
The lack of blade cores and the low percentage of blade’s simple debitages support this hypothesis that the blades were imported into the site in already-prepared form and then retouched at the site. In the Touq Tepe lithic industry, there was an emphasis on flake production due to the availability of raw materials. The technical evidence over the debitages of stone artifacts of Touq Tepe confirms that debitages were detached from cores using direct percussion with a soft hammer or indirect percussion.

Acknowledgments
The financial supports for carrying out the excavation program of Touq Tepe Neka have been provided by the General Department of Cultural Heritage, Tourism and Handicrafts of Mazandaran Province. We are also grateful to the Research Institute of Cultural Heritage and Tourism and the Iranian Center for Archaeological Research for issuing the excavation permit. The members of the excavation team, who were students of University of Mazandaran and experts of the mentioned General Department, cooperated and worked hard in the terrible conditions of the corona virus; these loved ones are also sincerely appreciated.

Abstract
The central plateau and southwestern Iran were two pivotal points to begin social and economic developments during the second half of 5th millennium BC, which played an important role in commercial exchanges and cultural interactions between the east and west of the Iranian plateau in the 4th millennium BC. Technology and industry were the main indicators of complexity in the central plateau, while in the southwestern of Iran, agriculture, animal husbandry and water resources were important in this sense. The level of complexity, the appearance of management technique, and pottery production in the key excavated sites in a range from the central plateau to a part of the eastern plains of central Zagros and the and southwest of Iran, was evaluated and studied. The structural analysis of the interactions between the two regions with a cultural ecology approach and based on five paradigms including assimilation, specialization, synchronization and self-organization, condensation of geo-economy, and concentration of power has shown that some societies during the second half of the fifth millennium BC, based on these five principles, they strengthened each other and created complex societies. We have achieved some results in the framework of economic-sociological indicators which include the creation of production and distribution systems, efficient families, pyramids of power and super elites, the destruction of public consensus and expanding elites. 
Keywords: Complexity Indicators, Central Plateau, Southwest of Iran, Pottery, Management Technique.

Introduction
Due to its economic, cultural and geographical capabilities, Iran has always been at the center of transportation routes. Based on the available settlement maps, the dense and compact geographical structure of the southwest Iran caused the integration and unity of settlements and ultimately the formation of early states. On the other hand, the scattered geographical context of the central plateau had caused its social fragmentation. 
The current research is based on the following questions and hypotheses: 1) how can the studies on the indicators of socio-economic complexity in the central plateau and southwestern Iran in the second half of the 5th millennium BC be evaluated? What are these indicators and why and how did they cause complexity? 2) What does the comparative study of the process of socio-economic complications in the central plateau and the southwestern region of Iran indicate?
Technologies such as pottery and metalworking, intra-regional and extra-regional relations are the main reasons, and agriculture, animal husbandry and exploitation of ground water and irrigation are secondary indicators of the complexities in the central plateau. In the southwest, agriculture, animal husbandry, exploitation of ground water and the intensive agricultural system in the western and eastern Shushan plains and the rainfed system in the middle and high plains (Dehlran plain) are the main characteristics. It seems that the residents of these two regions acted based on adaptation of surrounding environment. The theory of Special Evolution of Culture and interaction between humans and the environment can be used to interpret this topic. They used similar indicators in the process of complexity, but followed different paths in terms of quantity, quality and prioritization of the use of the mentioned indicators.
In the current research, the required documents have been collected through library studies. The method of analysis is to use the method of explaining cultural changes and using theories of socio-economic complexity.

Structural analysis of the interactions of two regions
In the second half of the 5th millennium BC and especially in the late 4th millennium BC, each of the five mentioned paradigms, on the part of the more advanced societies, not only did not endanger the old civilizations, but they strengthened each other and important results brought.
A) Standardization (assimilation): Regions such as the central plateau where the industry formed the basis of daily work and activities, needed standardized weight and measure tools. By applying the principle of standardization, many differences were eliminated or regional and local differences were distinguished from other places. An example in this regard is the making and decorating of pottery in regions such as Shushan, Fars and Central Plateau (such as dot motive pottery, plum ware, and Cheshme-Ali); which provides the possibility of rebuilding inter-regional cultural and ultimately political boundaries.
b) Specialization: With the acceleration of the division of labor, the expert, who only specialized in one profession, took the versatile villager place who worked intermittently. In this way, there was an opportunity for some specialist groups to monopolize the relevant knowledge and specialized professions emerged. The evidence of ancient metalworking in Zaghe, Uzbaki, Cheshme-Ali, and Tepe Gabrestan, as well as the similarity of inscribed buff ware from layers II-V of Qara-Tepe Qomrud with Rahmat-Abad, Gap, Chogha-Ahovan, and Geser sites, is a symbol of the level of specialization.
C) Synchronization (self-organization): Sometimes the concentration of power in societies will cause multiple pressures; and self-organization refers to the formation of patterns that were related to the endogenous factors of societies, and finally, this discipline became evident in a factor called management technique that it leads to the emergence of specialization and convergence. The similarities of the management technique of these regions can be found in the similarity of the seals of Qara Tepe Qomroud and Sialk with Giyan V, Shush A and Bakun A.
d) Density of geo-economy factors: When the economic capabilities of states depend on geographic issues, a geo-economy is formed, whose main goal is not to achieve physical power, but trade and commerce. The geo-economic position of the Central Plateau in line with the industrialists and southwest of Iran in line with increasing agricultural production and regular and permanent surplus production (relying on the data of irrigation canals obtained from Mahme, Sabz and Musian) and growth the development indicators.
e) Concentration of power and stability: the construction of buildings with a view and structures with a special spatial arrangement, such as temples and monuments such as the adobe platform of Shush, Farrokh Abad, Chogha Mish, Jafar Abad and the patterned structures of Zaghe are a sign of the concentration of power for supervision. On economic and religious technological activities.

Conclusion
The five principles proposed in the factions of societies that were becoming more complex were used almost identically and strengthened each other; created some of the most powerful administrative organizations in the societies from 4500 BC and then the 3rd millennium BC and left his special stamp on the civilizations of the 4th millennium BC.
Therefore, the results obtained from the five paradigms in line with economic-sociological indicators led to the creation of production and distribution systems. Early societies, based on their needs, started “necessary innovations”; the appearance of tools and development of the accounting and counting systems are some changes that have happened in Qomroud, Geser, Zaghe, Shush and related sites. Creating efficient families is another result. The nuclear family with relatives could have a standard model.
Some nuclear families were superior to others and caused complexities. Tribal territories are clearly visible in the settlement pattern of the southwest Iran. Chogha Mish and Shush 15 hectares expansion shows the preference of some households over another. Following this issue, pyramids of power and super elites were formed. The technologists and experts of power, who were in charge of the leader, were themselves organized in the hierarchy of elites and sub-elites, and in turn, they were integrated by the comprehensive elites, which consisted of people with various specialties; such as the control of central locations such as Zaghe, Qomroud, Shush, Chogha Mish, Farrokhabad, Bayat, and Jafarabad.
On the other hand, the people had similar and basic needs, and the other hand, a factor called public consensus was considered an attainable goal which its collapse discredited the concept of leadership; sometimes there was a possibility of this event which its analysis is very difficult. Most of the sites of this period, after an amazing prosperity suffered a gradual collapse. The expanding elite is another case in this regard. 
An important factor called the burden of decision is always up to the few who can handle it, unless the number of decisions increases and the decision load abilities of the old ruling groups become weaker; then new elites were placed at the head of affairs in recent periods so that they could handle the decision load burden. Therefore, the level of participation in a society can be less depend on culture and political wills and more about the result of decision-making. Frank Hole considers the organization of the late 5th millennium BC of Susa and its administrative positions to belong to religious people or the existence of a state with hereditary classes. It is not unlikely that centralization occurred in these societies.

Acknowledgment
This article is extracted from the thesis of the first Author entitled “Comparative study of the trend of socio-economic complexities in the central plateau and southwest of Iran in the second half of the 5th millennium BC” which is worthy of the material and administrative support University of Mazandaran Research and Technology Vice-Chancellor, Faculty of Arts And the architecture and archeology department are grateful.

Observation Contribution
The Authors declare that according to the extraction of the article from the doctoral dissertation, the writing of the article was done by the first Author with the guidance and supervision of the second Author and the consultation of the third Author.

Conflict of Interest
The Authors, while complying with the publication ethics, declare the absence of conflict of interest and material and administrative support from University of Mazandaran Research and Technology Vice-Chancellor, Faculty of Art and Architecture, and Department of Archeology.

Abstract
Analyzing why and how food collecting and production has been occurred in past societies has always been one of the main archaeological and anthropological research question. This work is done using archaeological finds, especially pottery. In this research, we tried through study of Yaqut Tepeh pottery usage to understand the socio-livelihood situation of East Mazandaran from the 4th to the 2nd millennium BC. In terms of use, potteries were divided into three categories: kitchen wares, food storage containers, and daily uses containers. Various variables such as clay, construction stages, decoration and form have been considered. Chi-Square and Kruskal-Wallis tests were used to analyze the relationship between the mentioned variables and the relationship between the use of pottery and each of the locus consequently. The socio-economic situation is the specific question of eastern Mazandaran communities from 4th to 2nd millennium BC. Probably this event took place in the east of Mazandaran, which is the intersection point of different cultures and the gateway to the Gorgan Plain and Central Asia on the one hand, and the southern slopes of Central Alborz and the Shahrood, Damghan, and Semnan plains through the mountainous plains, has happened. There is a significant relationship between kitchen pottery and food storage containers with some locus; but this relationship is very weak on daily uses containers. In the middle of the settlement and lifetime in this site, more and more diverse pottery was produced and a certain standard and legality was observed in the production of pottery. The variety of uses of containers as a sign of increasing the diversity of the diet can be one of the reasons for the social and subsistence life of Yaqut Tepeh community to become more complicated from the third millennium BC onwards.
Keywords: Social Life and Livelihood, East of Mazandaran, Yaqut Tapepeh, 4th to 2nd Millennium BC, Pottery Usage.

Introduction
Since pottery is the most abundant and perdurable archaeological data, it is necessary and useful to study it in various dimensions and aspects. Recording, description, classification, typology, seriation, and analysis of pottery are very important. In fact, the detailed study of pottery, as well as posing questions and hypotheses, creates a strong analytical foundation for explaining cultural changes, and archaeological interpretations and explanations. If at this stage, archaeologist doesn’t succeed obtaining a relative scientific understanding of the pottery collection, the subsequent studies, including the technical and laboratory investigation methods, will not produce reliable scientific results. Therefore, understandings the function of pottery for social, economic and religious-ritual (cognitive) reconstructions are based on this stage, and basically, the laboratory study of pottery, which itself leads to the material culture knowledge, produce quantitative and technical data for confirmation and support of the mentioned reconstructions. The high abundance of pottery in ancient contexts provide the opportunity to learn about why and how this material became important and even the sanctity of this material among generations and the study of lifestyle changes, regional and extra-regional communications, the socio-economic status, beliefs, customs, rituals, symbols, and familiarity with the perceptions of the ancients the archaeologist (Shepard, 1974; Orton et al., 1993; Costin, 2007; Roux, 2019; Criado-Boado et al., 2023; Shortland & Degryse, 2019). 
From the 4th millennium BC, fundamental changes took place in the West Asia; large settlements using the irrigation-based agricultural system emerged; the level of knowledge and specialties had reached its maximum growth; innovations such as rapid pottery wheel and the production of more diverse stone tools and implements emerged; early governments tried to expand their political and economic influence in wider geographical areas; and communities in different regions were trying to participate in these social and economic developments.
The Gorgan plain and eastern Mazandaran plains played their role in the cycle of social and economic activities of the 4th millennium BC (Cleuziou, 1986; Deshayes, 1968). Pottery and its related technologies are important data that are useful to explain the aforementioned developments in this region.
The present article main aim is the studying the usage of pottery on reconstruction of the social and livelihood situation in eastern Mazandaran plains from the 4th millennium to the beginning of the 2nd millennium BC based on the unearthed pottery from Yaqut Tepeh excavation.

Discussion
In order to study the socio-livelihood situation of Yaqut Tepeh, it is necessary to determine the usage of pottery, and therefore, the technology of pottery making must be studied first. The study of pottery clay (texture and amount of temper), the stages of making pottery (external and internal surface of pottery), decoration and its relationship with the form of pottery can determine the usage of wares. In this article, the relationship between these variables has been measured using the Chi-Square and Kruskal-Wallis tests. Based on the results of this tests, there is a significant relationship between them. Therefore, Yaqut Tepeh pottery is divided into three categories in terms of usage, which include: kitchen wares, food storage containers, and daily uses containers. Kitchen wares have temper and has a rough texture. These potteries are resistant and shockable due to temperature change and sudden impact. Another feature of these containers is the faster heat transfer. The form of these potteries is cauldron, drainage and cauldron cap (?). Cauldrons are of several types; two colors, single color and big cauldrons. Daily uses containers are in many different forms and have more decorations.
Food storage containers are in the form of bulgy jars and open mouth jars, each of which is divided into different categories. Each of these pots had a different use. Some were used for short-term food storage and others for long-term food storage. The relative chronology of the pottery, which was done by comparing them with the pottery of the neighboring areas, shows that the oldest settlement in Yaqut Tepeh appeared in the Middle Chalcolithic; Locus 15 of trench 9 potteries are comparable to Hesar II pottery in terms of manufacturing technique, design, and form. Settlement in this site continued until the Iron Age. Yaqut Tepeh have had trans-regional connections since the beginning. The red and gray pottery of the Gorgan plain has also been seen in this site.

Conclusion
Based on the relative chronology resulting from potteries and the arrangement of locus, the settlement in Yaqut Tepeh started almost from the Middle Chalcolithic and continued until the Iron Age. Due to its location in eastern Mazandaran, it has the possibility of more communication with the Gorgan plain and the central plateau of Iran. We said before that recognition the usage of potteries plays an important role of understanding the aspects of social life and livelihood of the ancient communities. This issue has been addressed by using the technical studies and Chi-square and Kruskal-Wallis tests. 
The potteries were divided into three categories including kitchen wares, food storage containers, and daily uses containers. Pottery paste (texture and temper), manufacturing techniques, decorations and forms were the basis of this classification. All potteries with a rough and sandy texture because of their resistant to temperature changes and sudden shocks has been used for cooking. Therefore, in addition to the cauldron, there have been other wares among the kitchen wares, including drainage, open-mouthed jars, and cauldron cap. Due to the large size of food storage pots, a little temper is used in them; because temper prevents the pottery from cracking during drying. These potteries are undecorated. Pottery with daily use is very diverse and often delicate and decorated. 
The relationship between these wares and locus was measured in order to study social and livelihood developments; a relatively strong relationship has been identified between the form of kitchen wares, food storage containers and locus. But there is not much connection with food storage pots. The aforementioned tests and pottery technology have shown that certain rules and standards have been common for production of pottery in Yaqut Tepeh. The variety of pottery from the Middle Bronze Age shows the dynamism of this community. The hypothesis of the site inhabitants diet diversity also shows their social and livelihood complexities. 
The current research is an initial step recognizing and defining the concept of society from Middle Chalcolithic to Iron Age in eastern Mazandaran, where there isn’t much knowledge in this field. Naturally, a foundation has been created for future research.

Abstract
One of the facts that can be seen in the archaeological contexts of the late Bronze Age in the abandonment or excessive reduction of the enclosures. At the end of the Bronze Age, many sites and settlements in the Iranian Plateau and outside the Iranian Plateau collapsed suddenly and unexpectedly, or the growing process of these societies has stopped. Researchers have considered several factor such as floods, earthquakes, immigration of newly arrived ethnic groups, etc. for this event, to these factors we can also add the effect of factors such as over urbanization, which has not been addressed much. As a result of over urbanization, challenges such as; Regional thermal changes, destruction of habitat and biodiversity and ecosystem as accelerating factors in the crises of this period could further worsen the situation. The result of this research show that after the increase in population in urban centers due to the lack of administrative planning to control the conditions caused by dense urbanization and as a result the disruption on environmental order and natural balance, the society has tried to restore the natural conditions as a stable system this attempt to return to the balance has been manifested in various ways, such as the decision to leave large settlements and move to peripheral and peripheral areas with sufficient food and water resources. The evidence of this event can be seen in areas such as Merv, Northern and Southern Balkh, and Doab areas in eastern Sind; in some cases, the crisis in the societies has increased and it has appeared in the form of newer problems such as famine and epidemics, inter regional conflicts and such things, which have led to the collapse of societies.
Keywords: Bronze Age crisis, Late Bronze, Over Urbanization, Eastern Iran, The Decline of Settlements and Civilization. 

Introduction
Over urbanization or excessive urbanization is generally used in cases where the urban population has grown unplanned and beyond the capacity of the environment and city administration, which causes the transformation and sometimes degeneration of urban communities (see Sovani, 1964). Therefore, the increase in the number of the population and the lack of environmental resources in the administration and organization of the urban population could act as a factor to disrupt the path of the Bronze Age societies. The decline of settlements and civilizations at the end of the Bronze Age is very important, and the first major collapses of the prehistoric era took place at this time, which occurred widely and in large areas of the old land. The Bronze Age in the archaeological literature refers to a period when societies gradually more from rural to more complex or urban and create trans-regional connections. Obviously, what is expected is the continuation of the development and progress of societies towards the emergence of larger and more complex civilization and states, which reached their peak of prosperity during the middle Bronze Age (see Tosi, 1976: 168). But what happened in the late Bronze Age is the abandonment of sites and depopulation of a large number of them, which can be seen as a chronological break in many Ancient sites? The evidence indicates an event during which large settlements such as Shahr-I Sokhta (Tosi, 1968). Mohenjodaro (Wheeler, 1968), Harappa (Wheeler, 1968), Altin Tepe (Masson, 1981), collapsed, although some small settlements such as Tekem Tepe (Kohl, 1984) continued to exist without any interruption. The concentration of population in urban areas and the impossibility of providing in frastructure needs in urban life due to the occurrence of over urbanization had led to disorder in social structures and population decline in Mohenjodaro and Harappa settlements. If the elites of the society do not manage or solve the problems caused by excessive urbanization, difficult conditions will arise and the society will probably solve the problem or become a problem in the form of a self-organizing system. The evidence shows that in some settlements such as Mohenjodaro, Harappa and Altin Tepe, people decided to leave the large settlements and settled in peripheral areas, and this caused the settlements to become uninhabited in the late Bronze Age. 

Identified Traces
Urbanization, which was actually a cultural and social revolution, appeared sometime between the end of the fourth millennium and the beginning of the third millennium bc in western Asia, Egypt and Mesopotamia (Childe, 2019:1). But at the end of the Bronze Age in a wide area of the east, especially the southeast region of Iran and even beyond the current borders of Iran, such as; Central Asia and the Indus valley, many large settlements such as Shahr-I Sokhta (Tosi, 1968), Tepe Hesar (Schmidt, 1937; Dyson, 1989), Namazga (Kohl, 1981) area have declined and shrunk excessively. There are several theories about the crisis of the late Bronze Age, such as the invasion of the Aryan tribes (Girshman, 1954), disease (Robbins Schug et al., 2013), famine and earthquakes (Nur, 2009), etc., but since this discussion is about societies with an advanced level of technology and in constant relations with are their peripheral areas. The factor of excessive urbanization can be added to the above. Rapid urban growth will have consequences for the urban society. Such as the lack and absence of drinking water, urban heat island effects, unpredictable rainfalls, and increasing demand due to population growth cause environ mental destruction and air pollution. For example, in the Indus valley in period IIIC, due to extra-regional trade and large inward migrations, the previous organized settlement pattern was disrupted. The houses in the main areas of the city were thrown into the streets and then at the end of the Harappan phase, the population density decreased and some of them were concentrated in the main areas of the city and the other part moved to the east. In Turkmenistan, even though the archaeological data indicates a decrease in the Kopedagh area, no settlements are abandoned in Atak and other areas, especially Merv and Balkh.

Conclusion
In general, based on archaeological findings, the cities were formed from the old Bronze Age and reached their peak of prosperity during the middle Bronze Age. But at the end of the third millennium and the beginning of the second millennium B.C. the evidence indicates that the sites were excessively shrunk and empty of inhabitants, or the collapse of large settlements. This could have been caused by over urbanization on the basis that whenever the society’s population grows beyond the environmental resources and facilities necessary to organize people, it can create crises for urban societies. Crises such as; the increase in urban rainfall and temperature, the increase in urban waste, the lack of drinking water sources and the destruction of the environment for human well-being in large societies with high population. With the increase of urban population and the lack of resources to organize people it leads to an increase in crime, marginalization and disorder in urban organization, and when the political rulers cannot solve or manage the created problems, the people of the society left the cities and went to the marginal and peripheral areas with stable food and water resources, such as Merv, Northern and Southern Balkh, to continue their lives.

The site of Velem is located approximately 500m from the village of Velem, about 36km from Behshahr in the east of Mazandaran province. In 2020 during the construction of a road near the village, this cemetery site was accidentally discovered. In the following year, the rescue excavations were conducted, and burials from pre-Parthian and Parthian period were uncovered. In the first season of excavations twenty-six shaft burials from Parthian period were revealed. This study focuses on the Parthian burials. Since there is limited knowledge about the historical era of northern Iran, especially Mazandaran, the results of excavation at Velem are particularly significant. Furthermore, only a few Parthian sites have been identified in Mazandaran, and the historical knowledge of northern Iran during this period is also limited. In this article, with a descriptive-analytical approach, we try to study the findings from Velem in the first season of excavations to answer the following questions: 1) What is the structure of the graves and the burial methods at Velem? 2) Considering the prevalence of shaft burials in northern Iran, what is the origin and cause of the spread of this burial practice in this region? The field study results show that the Parthian funerary type identified at this site is shaft burial including a corridor, entrance, and burial space. Additionally, a comparative analysis of the graves at this site with similar examples in northern Iran and beyond suggests that this type of burial was common among nomadic peoples. Given the geographical location of northern Iran, it is very likely that this funerary tradition was penetrated to region by north-eastern nomadic population as the movement of a group of nomadic people of Dahae, or it was appeared as a result of the close interactions between nomadic and settled peoples.