Land management during the Bronze Age in the Upper Seine Valley (France): Isotopic evidence for selective land-use

During the Bronze Age, the Upper Seine Valley, in northeastern France, was a dynamic region, at the confluence of two rivers and at the crossroads of two cultural entities. Initially aligned with the Atlantic cultural sphere, the area experienced an increasing influence from the Tumulus culture between the 14th and 11th centuries BCE. This interaction led to significant transformations in material culture and funerary practices, notably with cremations becoming the main rite. To understand the underlying factors behind these changes, the study focuses on human mobility and interactions during this period. Strontium isotope ( 87 Sr/ 86 Sr) analyses were conducted on 100 cremated human bones from eight archaeological sites in the Upper Seine Valley. In parallel, 96 modern plants were analysed to develop a high-density local bioavailable strontium isoscape. The results reveal the presence of two isotopically distinct human groups, each associated with different land-use strategies. While part of the population sourced their food from the southern Yonne river basin, others favoured the Seine-Yonne confluence area, suggesting structured patterns of resource acquisition. In addition, isotopic outliers indicate mobility between these groups, with one case likely reflecting maternal mobility during pregnancy. With a detailed local baseline and a method adapted to cremated remains, this study provides a refined understanding of population dynamics at the end of the Bronze Age. Working within a well-documented archaeological context and focusing on a restricted area enabled a new understanding of land-use dynamics in the Upper Seine Valley during a key period of cultural transition.