The Chalcolithic period (ca. 4900-3500 BC) is marked by the progressive development of an interaction sphere that included the Caucasus, Eastern Anatolia, North Mesopotamian, the northern Levant and North-west Iran. This interaction sphere, which has been called the Chaff-Faced Ware oikumene (Marro 2010, 2012), may be described as a period of increasing mobility between the communities living in the lowlands (Mesopotamia and northern Syria) or around lake Urmiah in Iran, and human groups living in the highlands of Eastern Anatolia and the Caucasus.This paper will draw on the cross-analysis of two series of artefacts: 1° the geochemical and petrographic data obtained from Chalcolithic painted potsherds collected on the settlements of Uçan Agil (Nakhchivan, Azerbaijan) and Dalma Tepe (Iran), in order to assess the relationships between the two sites. 2° the geochemical data from a series of obsidian artefacts collected on a dozen sites located in Nakhchivan and North-western Iran.From the distribution patterns of these two classes of artefacts, we will examine the conclusions that may be reached on the development of circulation networks between Iran and the South Caucasus, and their implications for interpreting the mobility patterns during the Chalcolithic.Read less <