Investigating the human-environment relationship of early intensive salt production: A case study from the Upper Seille Valley, Lorraine, northeast France

This paper presents the latest findings of multi-disciplinary research into the human-environment relationship of intensive Iron Age salt production in the Upper Seille Valley, Lorraine, northeast France. Investigations focus on the early Iron Age workshop “La Digue” (~ 625-500 cal BCE; Hallstatt D1-2), where high-resolution borehole sampling has been coupled with conventional excavation and geophysical surveying to establish direct linkages between intensive occupation and the alluvial environment of this site. Detailed insights into human-river interactions have been identified, enhancing current understanding of the environmental context and impact of this important early industry. The workshop's palaeogeographic setting has been reconstructed and new evidence for briquetage disposal practices has been identified, confirming that a close relationship existed between salt-making and the local hydrological regime. A large volume of briquetage waste (broken clay-fired salt-making equipment, ash and charcoal) was dumped into the river at La Digue, causing rapid and deliberate channel blockage, increasing the distance between the workshop and the river. This probably contributed to a localised increase in channel mobility and/or flooding whilst the workshop was active, producing challenging conditions for salt production. The workshop was abandoned following an intense flood event in ~ 500 cal BCE, coinciding with a major hydrological shift towards wetter floodplain conditions, likely arising from a combination of natural and anthropogenic factors. This study demonstrates the importance of understanding the environmental context of salt production and the roles of water management and briquetage disposal practices, which have been largely overlooked at other intensive salt making sites that employed the “briquetage technique”.