Abstract
Central Zagros as one of the significant Iranian archeological perspectives has attracted the attention of many archeologists during the recent century and especially from the 1950s. It seems that the rugged lands of this near east region have been the cradle of many cultural evolutions during the history and the prehistoric periods. Although central Zagros due to its adjacency to the central Iranian plateau, Mesopotamian and southwest of Iran lowlands, and also the northwest mountains of Iran has been of concern mostly for the cultural remnants of the prehistoric societies, yet it has been a strategic and important region during the historical and even Islamic period. Among them we can mention the complex of Taq-e Bostan on the north of Kermanshah located on the ancient path of “The great Khorasan road”. This complex is on the hillsides of Parkuh and surrounded by thickets and a lake which cause it a particular situation throughout the history. This complex owes its fame to the Sassanid rock relief which has been visited by Abeh Pushan in 1792 for the first time. However, Herzfeld studies are the first scientific investigations on the historical complex of Taq-e Bostan. On the other hand, the
conducted excavations by Mr.Kambakhshfard in 1969 led by the accidental discovery of some pithos graves by municipality workers, resulted in achieving the evidences of a Parthian cemetery with more than 50 pithos graves and also remains of a village related to Parthian period. According the archeological investigations and studies on the ancient paths of the western Iran, or the surveys have been done in the region and ninety years background of archeological studies about this area, no report regarding the prehistoric existence of this complex has been presented. Morad Hasel site is the closest prehistoric site to this complex which has been identified and surveyed by Mr. Hassan Rezvani and it is related to the chalcolithic and Bronze Age. During the surveys and visits of Ali Hozhabri in the summer of 2013, some evidences of a chalcolithic site have been identified in the western park of Taq-e Bostan complex. This site was surveyed and its surface findings were transferred to the C.H.H.T organization for filing and documenting. Regarding the nature of the findings which were collected during the field survey, the aim of the present study is to introduce this significant site and to present a relative
history for the site’s artifacts. In the following, the overall image of cultural structure of this site is recon structed with an analytical view and with regard to the chronology and the location of this site.
Keywords: Central Zagros, The Western Park of Taq-e Bostan, Chalcolithic Age, Kermanshah.

Conclusion
This site is located on the north of the current city of Kermanshah, Taq-e Bostan historical complex; with northern longitude of ″16 ′23 °34 and eastern latitude of 47″54.7′7°. Altitude of this site from the sea level is 1395 m and is one-kilometer length and 300 meters width. This site is located on the west of Taq-e Bostan, in the western Park of the complex and on the hillside, surrounded by pine trees and close to a basin with a boiling fountain. This basin known as Taq-e Bostan Sarab is one hundred meters far from the east of the site. The site is one kilometer far from the north of Qarasu River. On the rather steep slope of the mountain and some deep clefts have been made on its both sides by heavy equipment. The Parthian cemetery of Taq-e Bostan is formed on the Taq-e Bostan western park site’s remnants. Fortunately, the pine jungle around this site has prevented the urban construction and the field is preserved. However, since the Parks and green spaces organization of Kermanshah is beside the site, and in 2005 Kermanshah municipality decided to build a parking in this area and started to excavate in two parts of the site. The result of this earthworks were discovery of some Parthian pithoi graves which were unfortunately destroyed; although C.H.H.T stopped their progress but those clefts are still obvious and gradually they turned in to a dumping ground for city wastes and building debris. Later the municipality started to expand the west Park area of Taq-e Bostan with some changes. Except the known sites and caves around Taq-e Bostan which are far from the historical monuments, up to now Taq-e Bostan complex has been known and studied for its Parthian, Sassanid and Qajarian cultural remnants. Discovering a prehistoric site in this complex can emphasize its importance, not only for the historical and Islamic period but also the prehistoric (Chalcolithic) period. The Godin excavations can be considered as the base for western Iran chronology of central Zagros, but it seems that contrary to Kangavar plain, and in compare to eastern plains of Zagros, Mesopotamian ceramic culture was more widespread in the western plains of central Zagros such as Mahidasht during the fourth millennium B.C. accordingly, the chalcolithic chronology in Kermanshah and Mahidasht plains can be studied based on the excavations conducted in Siyahbid and Chogha Maran. Based on the chronology of the neo-chalcolithic period of this site which its evidences have been obtained on the workshop no. 3, handmade red ware and black ware ceramics with black decorative patterns have been found related to this period. The proposed date for the neo-chalcolithic of Mahidasht is 3000 – 3600 B.C; comparison of the discovered ceramics indicates  the concurrency of this site with GodinVI: 1 and neo-chalcolithic layers in Siyahbid and Chogha Maran. Clearly, ceramics are the most important and significant cultural material of the near east. Due to the degradation and destruction, the surface cultural material of this site is just shreds. The neo-chalcolithic ceramics of the western Park of Taq-e Bostan complex are buff ware with vegetal temper and light red coating color. These ceramics are handmade, properly baked and medium quality. Among the surface ceramics of this site, no patterned shred was found but regarding the appearance of these ceramics, they can be related to neo-chalcolithic, specially the common rolled Rim bowls have been seen among the collected samples of the surface. Considering the clefts in this site made by the blades of the road construction equipment, the cultural material accumulation can be seen in this site. Ceramics are this site is comparable with the ceramics of GodinTepe in Kangavar plain and Siyahbid in Kermanshah plain.
 

Abstract
The Chalcolithic Age is one of the most important prehistoric periods in Iran. The transformations of this period in the Central Zagros have emerged in continuation of the Neolithic period.  One of the important areas of Central Zagros, which had many settlements related to the Chalcolithic era, is Silakhor plain in the north of Lorestan. Despite the cultural richness of the Silakhor plain during the Chalcolithic Age, no purposeful study has been conducted to clarify the Chalcolithic status of this area. In this regard, in order to clarify the settlement models of the Chalcolithic era of Silakhor plain, this study is presented, which is a summary of Ahmad Parviz’s archaeological studies and purposeful studies by the researchers, In the present study, the authors have tried to find the answer to the following questions: What were the settlement models of Silakhor plain in the Chalcolithic era? How can the changes of settlement models in the old, middle and new periods of the Chalcolithic era of Silakhor plain be analyzed? It seems that several factors including water resources, altitude of Silakhor plain and state’s roads have been effective in the formation of settlements in this area during the Chalcolithic age. Studies conducted in this plain so far have shown 80 ancient sites related to the Copper Stone Age. Some of these sites involve all three periods of old, middle and new Chalcolithic era. The spatial data collected in this research have been studied by GIS science studies method and implemented in ArcGIS 10.3 software. The basis of these studies is the distance of each settlement area from the nearest river and its altitude level from Silakhor plain. These maps have been implemented in all three periods of old, middle and new Chalcolithic Age of Silakhor plain. 
Keywords: Central Zagros, Silakhor Plain, Chalcolithic Age, Settlement Models, GIS.

Introduction
The Chalcolithic Age (mid-fifth millennium to late fourth millennium BC) is one of the prehistoric periods which has witnessed important transformations such as population growth, enhancement of the quality of pottery, the use of copper metal, improvements in the quality of settlement construction and so on.  Some scholars consider this period to be a continuation of Neolithic transformations and some consider it as being independent of other periods. Archaeological studies conducted over the past few decades in the Central Zagros region have shown that this area has seen an increase in population during the Chalcolithic period. This increase in population is inferred from the number of archaeological sites recorded in this period compared to the previous period (Neolithic). Of course, the studies indicate that archaeological studies conducted in connection with the Chalcolithic Age of the Central Zagros, have focused mainly on the Gamasiab River Basin.
Silakhor plain has a suitable situation geographically and climatically.  The flat plain and fertile soil along with sufficient water resources have caused us to see a large number of ancient sites from the Neolithic period to recent centuries. Despite the conducted studies, so far no purposeful studies have been conducted to analyze the residential and settlement situation of the Chalcolitic era of Silakhor plain. In this regard, the researchers, while exploring the studies conducted in this plain, have re-examined the ancient sites of the Chalcolithic era of this plain. Since the area of Silakhor plain is located in Boroujerd and Doroud counties and covers a large part of the north of Lorestan province, in this research, this plain is divided into two parts, north and south, the northern part of which is in Boroujerd and the southern part is in Dorud city. In order to study the situation of the settlements of Silakhor plain more accurately, its northern part in Boroujerd city has been chosen. 

Findings
The chronology of the Chalcolithic age of Silakhor plain and the east of Lorestan is also influenced by the chronology of the Gamasiab river basin and the Kangavar valley. The study and identification of the archaeological and historical monuments of this area has been done recently by Ahmad Parviz in 2006 and the review of the researchers in line with this research has been done in 2016.  In this study, according to Godin chronology, areas related to the chalcolithic age during three periods of old, middle and new era are studied. Sites are evaluated by the ArcGIS 10.3 software after being located on elevation maps through their Universal transverse Mercator (UTM).  In this evaluation, the altitudes of the area compared to the average altitude of the northern half of Silakhor plain and also their distance to the nearest rive, are examined. In the studies performed, it has been determined that 80 sites are belonged to the Chalcolithic age of the northern half of Silakhor plain, some of which include all three periods of old, middle and new Chalcolithic era.
 Of all 80 Chalcolithic Age sites in the study area, 25 sites are related to the old period. These areas are mainly distributed in the central parts and in the plains.  Most sites are at altitudes between 1,500 and 1,600 meters above the sea level.
Of the 80 Chalcolithic Age sites in the study area, 31 sites are related to the Cenozoic Ages. These sites, like the old period, are mainly distributed in the central parts and in the plains. Most sites are at altitudes between 1,500 and 1,600 meters above the sea level.
Of the 80 Chalcolithic Age sites in the study area, 42 are related to the Cenozoic period. These areas, like the old and middle periods of the Chalcolithic Age, are mainly distributed in the central parts and in the plains. Most sites are at altitudes between 1500 and 1600 meters above the sea level.

Conclusion
In this study, it was found that the number of old, middle and new sites of the Chalcolithic Age in the northern half of Silakhor plain (Boroujerd) are 25, 31 and 42 , respectively. This indicates that the Copper Stone Age in this area has developed in a growing trend (in terms of the number of settlement sites). Increasing the number of settlements in this area paves the way for future transformations in the next period (Bronze Age).  Therefore, the beginning of urbanization in this area has had a strong and evolving introduction to the Chalcolithic era.
On one hand, the study of maps prepared in ArcGIS software shows that the vast majority of sites in all three periods in the Chalcolithic Age are located at an altitude of 1500 to 1600 meters (average height of Silakhor plain is 1500 to 1600 meters) and in the area of Silakhor plain.  On the other hand, the analysis of the distribution map of the Chalcolithic sites of this area shows that the settlements of this period have been formed depended on the water resources (rivers).