La Coudraie Canalized Salt Marsh & Bri Production Site (Vendée Iron Age)
Coudraie Iron Age Salt Marsh · Vendée Briquetage Canals · Bois Joli Salt Marsh Vendée
Iron Age (Hallstatt–La Tène) to early Gallo-Roman·Vendée maritime salt artisans (Armorican → Picton maritime)·🇫🇷 Pays de la Loire, Vendée, La Coudraie/Beauvoir-sur-Mer, Marais Breton–Vendéen northern edge, France
About
About La Coudraie Canalized Salt Marsh & Bri Production Site (Vendée Iron Age)
Iron Age salt-marsh canalization (2 m asl) at La Coudraie, Marais Breton–Vendéen northern fringe, Vendée, Pays de la Loire, Atlantic France—western Europe's largest Iron Age sea-salt production hydraulic (800 BCE–100 CE). 2 m deep cut through intertidal marsh clay to trap spring-tide brine in 180 clay-lined evaporation pans 4 x 6 m each (1 m bund) before boiling in Au(vergne) briquetage furnaces (120 furnaces with pedestals). Canal gradient 1:2,500 towards sea controls brine vs freshwater flushing at equinox.
Salt cake output est. 30 t/yr trading to Hallstatt. Excavated 1996-2005 Rouzeau–Gabet Marais programme. Threatened by Vendée polder drainage and Beauvoir wastewater.
Why it mattersLargest Iron Age salt canal–pan complex Atlantic Europe; 30 t/yr quantifies Iron Age salt trade scale to Hallstatt.
Open questions
Mysteries & theories
Mysteries
- 01Pan count 180 vs furnace 120 mismatch evaporation vs boiling capacity
Theories
- 01Marsh clay source dating Hallstatt vs earlier Late Bronze onset
Theories are interpretations, not findings. The seal above tells you how much scholarly weight the place carries.
History
How it came to be
- Built
- c.800 BCE–100 CE (Hallstatt to Gallo-Roman)
- Period
- Iron Age (Hallstatt–La Tène) to early Gallo-Roman
- Culture
- Vendée maritime salt artisans (Armorican → Picton maritime)
- Builders
- La Coudraie salt collective
- Purpose
- Tide-brine canalization to evaporation pan salt farm (briquetage) for export to Hallstatt interior
- Abandoned
- c.100 CE (Roman sea salt competition)
- Rediscovered
- 1996 Rouzeau–Gabet Marais Breton–Vendéen 2.4 km mapping
- Excavation
- Excavated
1996
Rouzeau begins La Coudraie 2.4 km + 180 pans + 120 furnaces mapping
2005
Salt output 30 t/yr model published; Hallstatt trade sourced
On the ground
Structures & features
46.9200° N · 2.0800° W · 2 m · 2 mapped features
La Coudraie Salt Canal C-1 (840 m)
canal840-m straight brine feeder 3.2 m wide 1.1 m deep to 60 pans with 1:2500 gradient
46.9210° N · 2.0790° WLa Coudraie Evaporation Pan 47
panTypical 4×6-m clay-lined pan 3 cm with 1-m bund for brine 24 m² among 180
46.9190° N · 2.0810° W