Abstract
Archaeologically, the northeast region of Iran is one of the least-known regions in the Iranian Plateau. The reasons for this situation is multifold; some of these include rarity of archaeological investigations, its vastness and the associated restrictions such as desert areas and impassable mountainous areas. The present paper deals with the chronology of and investigations at one of the key sites of the eastern Iran: Tappeh Mokhar. This is site is located to the east of the town of Torbat-e Jam, by the river of Jamroud. Archaeological finds from this site include a vast spectrum of items, including chipped-stone artefacts, ceramics, stone vessels, and clay figurines, of which ceramics are the most numerous. These finds have been recovered from delimitation soundings, and archaeological reconnaissance. The main objective of this paper is to introduce this important, multi-period site through the recovered materials before it suffers from further damage which at present made it as a depot of waster of modern construction materials. In this paper, a classification and typology of the ceramic collection from the site has been provided and then, based on comparative studies, their relative dating has been suggested. This research follows a historical approach and has been fulfilled with a descriptive-comparative method. The main queries are: which periods can be inferred from the studies of the recovered materials of Tappeh Mokhar. What are the characteristics of Mokhar ceramic assemblage and which types of ceramics of which periods can be identified in this assemblage? The preliminary studies of the ceramic assemblage, however, suggest that the site was occupied during Chalcolithic period, Bronze Age, Achaemenid and Parthian periods, and its ceramic types are comparable with sites of the northeast region, Turkmenistan and eastern region, and then with those of north, south, southwest and west of Iran.
Keywords: Tappeh Mokhar, Khorasan (Torbat-eJam), Bronze Age, Namazga 3 & 4, Achaemenid, Parthian.

Introduction
Archaeologically, the northeast region of Iran is one of the least-known regions in the Iranian Plateau. The reasons for this situation is multifold; some of these include rarity of archaeological investigations, its vastness and the associated restrictions such as desert areas and impassable mountainous areas. The present paper deals with the chronology of and investigations at one of the key sites of the eastern Iran: Tappeh Mokhar. This is site is located to the east of the town of Torbat-e Jam, by the river of Jamroud. Archaeological finds from this site include a vast spectrum of items, including chipped-stone artefacts, ceramics, stone vessels, and clay figurines, of which ceramics are the most numerous. These finds have been recovered from two types of archaeological programs: delimitation soundings, and archaeological reconnaissance. The main objective of this paper is to introduce this important, multi-period site through the recovered materials before it suffers from further damage which at present made it as a depot of waster of modern construction materials. In this paper, a classification and typology of the ceramic collection from the site has been provided and then, based on comparative studies, their relative dating has been suggested. This research follows a historical approach and has been fulfilled with a descriptive-comparative method. In addition to chronology, the regional relationship of the site has been inferred from the comparative studies. The main queries of this research are: which periods can be inferred from the studies of the recovered materials of Tappeh Mokhar. What are the characteristics of Mokhar ceramic assemblage and which types of ceramics of which periods can be identified in this assemblage? The preliminary studies of the ceramic assemblage, however, suggest that the site was occupied during Chalcolithic period, Bronze Age, Achaemenid and Parthian periods, and its ceramic types are comparable with sites within the northeast region and beyond. In fact, the ceramic studies suggest that the cultural relation of Tappeh Mokhar was mostly with the population centers of the northeast region, Turkmenistan and eastern region, and then with those of north, south, southwest and west of Iran. 
Our information on the archaeology of eastern Iran and Khorasan is limited and those few research conducted few decades ago were concentrated on the sites in northern and central parts of the province. Tappeh Mokhar with its long sequence of occupation, representing at least four periods, provides a unique opportunity to study the cultural development in this part of Iran during the late prehistoric and historic eras. This research tries to provides a reliable chronology for the site based on studies of the ceramic collection recovered from both delimitation sounding and systematic surface sampling conducted at the site. Therefore, the main objective of this paper is the quantitative and qualitative studies of the recovered collection and provides their classification and typology.  
Research Question: There are two main questions in this research: Which periods are represented by ceramic collection and cultural finds of Tappeh Mokhar; What are the main characteristics of Tappeh Mokhar ceramic collection; Which ceramic types of which periods are represented in the collection; and what they suggest about the cultural interaction of the site from an intra-regional and inter-regional perspective? 

Research Method
The nature of this research is descriptive-analytical, and is based on literature review and analysis of the archaeological materials. The main bulk of the materials studied is ceramic collection, recovered from delimitation sounding and systematic surface sampling, which are analyzed on the basis on typology, technical characteristics, decorations. Finally, a relative dating is suggested for the site based on the aforementioned studies. 

Research Background
In 1975 two geologists, Ariai and Tiboult, conducted a fieldwork in north of the Torbat-e Jam County and in the Kashaf Roud basin, resulting in discovery of an important palaeolithic locale (Jam e Al – Ahmadi, 1387; Ariai&Thibault,1975:101-103; Khodadoust & et al. 1394:109-124). In 1975 and 1987, Bernard Ekin, and in 1988 Wilber and Glombeg published their investigation on the proceedings of Sheikh Ahmad Jami (Okeane, 1979; Okeane, 1987; Wilber& Golombek, 1988; Khodadoust & et al. 1394:109-124). In 2003 a large scale excavation and stratigraphy sounding at the Architectural Complex of Torbat-e Jam has been conducted by Mohmoud Toghraei (Labbaf Khaniki,1399:147). He also conducted a delimitation sounding at Tappeh Ghar of Torbat-e Jam in 2008 (Labbaf Khaniki,1399:151). The latest research about the Islamic Period Torbat-e Jam complex is coming back to the works by Ali Zarei, as part of his PhD dissertation (Zarei,1394). 
The first archaeologist who visited Tappeh Mokhar was Gunter Kerbel. He visited this site and also the Shah Abbasi Caravansarai complex in 1980 en route his trip to Afghanistan (See: Labbaf Khaniki,1391:144; Korbel,1983;18-57). After him, the area was archaeologically surveyed by Rajab Ali Labbaf Khaniki in 1985 on behalf of Iranian Center for Archaeological Research, in which many site from prehistory to Islamic period were identified (Labbaf Khaniki,1364). The latest research at Tappeh Mokhar was conducted by Hasan Nami, of Neishabour University, in 2017 with the aim of defining the limit of the site by delimitation sounding (Nami,1394). 

Conclusion
The study area in which Tappeh Mokhar is located is part of the Qara Qum Basin, subsuming in the Jam and Hariroud Basin; Hariroud River originates from Afghanistan and the Jam Plain is very fertile because of the river sedimentation. In addition to several other environmental potentials, this factor is one of the main reasons of foundation of Tappeh Mokhar settlement. Along with natural factors, both historical and cultural factors were responsible for establishment of settlements during different periods in what is now Khorasan. Due to limitation in conducting basic, archaeological and historical research, identification and picturing the historical occupation of the study area is confronted with difficulties. Yet, thanks to increasing research during last two decades, our understanding on the ancient communities of the area is developing. The endangered site of Tappeh Mokhar was chosen in this part of Khorasan for getting a better understanding on the prehistoric and historical human developments, which proved that the site is a significant settlement during prehistoric and historic eras. 
Archaeological research at Tappeh Mokhar consisted of two approaches: a systematic surface sampling and a delimitation sounding, in which 30 small trenches were excavated around the hypothetical perimeter of the site, inferred from both topography and concentration of the surface materials. Most parts of the site have been leveled during last decades and it was used as agricultural land and also a depot for modern construction wasters. Based on our comparative studies, the site represents occupations from late Chalcolithic, Bronze Age, Achaemenid and Parthian periods; the latter is thought to be significantly represented. Future excavations at Tappeh Mokhar would potentially answer some important questions about the nature of prehistoric and historic settlements in this part of Khorasan.

Acknowledgments
My heartfelt thanks go to Dr. Kourosh Rostaei (Associate Professor of RICHT), Dr. Mohammad Esmaeil Esmaeili Jolodar (Associate Professor Depart of Archeology, University of Tehran), Reza Haidareii (M. A of Archeology, University of Tehran), Dr. Hassan Basfa, Dr. Mohsen Dana and Dr. Seyyed Javad Jafari for their insightful comments on the manuscript.