Tracing social disruptions over time using radiocarbon datasets : Copper and Early Bronze Ages in Southeast Iberia

The transition between the Late Copper and the Early Bronze Age in Central and Western Europe saw large-scale social disruptions ca. 2200 cal BCE ('4,2 ka event'). Their source is much debated, and scholars have addressed the problem from various disciplinary perspectives. One account points to the westward migration of populations with Pontic-Caspian 'Steppe' ancestry, possibly favoured by the spread of infectious diseases, but the question remains open. In southeast Iberia, the shift from communal burial practices in the Copper Age to single and double tombs in the Bronze Age offers a reliable diagnostic feature for the transition. To investigate social and demographic changes in this region during the late 3rd millennium BCE, we resorted to new C14 dates from human bone samples originating from both kinds of funerary contexts. Our statistical analysis indicates that most probably the changes in funerary rituals in southeast Iberia were fast. It also implies that the local populations had dropped in numbers before 2200 cal BCE, so that the presence of 'Steppe ancestry' ca. 2200-2000 cal BCE could be the result of their admixture with neighbouring peoples. Finally, we suggest that more high-precision C dates and archaeogenetic analyses from this transitional period are crucial for addressing the formation of Bronze Age societies.