an impressed pottery sherd: a chalcolithic newfound in the southern highland of abharroud river basin

in prehistoric studies of iran, the abharrood river basin, located on the east of zanjan province and in the northwestborder of the central plateau, is one of the little-known and dark regions. studying this region according to itsenvironmental features and geographical location is important for understanding regional relations and interregionalinteractions between three cultural-geographical areas, the northwest, the west and the central plateau. so far, thisregion has not undergone major archaeological research and our knowledge of the nature of the prehistoric settlementsis imperfect.a new trend in regional archaeological research began with two seasons of surveys, in 2003 and 2005. these surveysshed a light on the past of this region. in the first season, the site of chakhmaqlokh, in the southern highlands of theabharrood river basin, was identified. in 2009, on a second visit, cultural material of the chalcolithic period and apottery sherd with a flat seal impression were collected from the surface of the site. it is likely that this sherd is theoldest piece of pottery with a seal impression that has been ever found in iran. therefore, valuable knowledge aboutimportant aspects of chalcolithic settlements in this region can be determined. after describing the area andintroducing the site, the authors study the surface material and introduce, compare and date the sherd.