On the small Breton island of Béniguet, off the coast of Finistère, archaeologists hope to talk about household waste trapped in the dune since the Bronze Age. A challenge that is both scientific and human. “We make the trash of people who lived there 4,000 years ago,” explains Yvan Pailler, archaeologist at the University of Western Brittany (UBO), in front of the excavation site. “This will allow us to analyze their economy, how they lived, to know what animal species they raised…”

Since 2021, exceptional excavation authorization has been granted on this 60-hectare islet in the Molène archipelago, classified as a nature reserve since 1993 and therefore prohibited from access. At the edge of the water, on a square of a few m2 dug in the dune, students and archaeologists explore a vast shell mass, trapped by the dune for millennia, before being exposed by a storm in 2014. The site contains several layers of detritus, divided into strata, the oldest of which date back to the Neolithic period.

The most widespread species in this heap of ancestral detritus is the limpet (or barnacle), this famous shell in the shape of a Chinese hat. This small grazing gastropod that lives on rocky foreshores has been eaten by islanders for millennia.

“We will be able to use these small limpets as climate archives and retrace the environmental and climatic history of the region”, underlines Jean-François Cudennec, marine biologist, who devoted his thesis to the limpets found on this site.

By analyzing the shells, it is indeed possible to sketch the history of the women and men who collected them. “We can determine the temperature of the water just before the death of the animal”, explains Jean-François Cudennec. “This information will give us the season in which these people were going to fish the limpet”. This then makes it possible to know “the seasonality of the occupation of the site” because “if we have limpets collected all year round in the piles, that means that people were there all year round”, adds the researcher.

Over the centuries, periods of permanent or episodic occupation have thus been identified. “We have both massive and permanent installations and small moments of life sealed by the dune massif”, describes Clément Nicolas, researcher in archeology at the CNRS (National Center for Scientific Research).

A specialist in societies from the 3rd and 2nd millennia BC, this archaeologist hopes to learn more about the way of life of Bell Beaker men, a culture then widespread throughout Europe, whose origin and rapid diffusion remain debated.

“We know this culture especially through the dolmens, the tombs”, as in Carnac (Morbihan), details Clément Nicolas. “We are starting to know the habitats. And there, we have the bell-shaped trash cans. This is already in itself a small revolution on the scale of Brittany.”

Especially since the dune, rich in limestone, preserves the bones very well, unlike acid soils. “Our dream would be to find a burial”, which would make it possible to trace the origin of these populations thanks to DNA analyses, confides the archaeologist.

The excavations, financed in particular by the French Biodiversity Office (OFB) and the UBO, could thus continue for several more years, despite the Spartan living conditions on the island, without water or electricity. “It’s a return to basics, a challenge, surpassing oneself,” smiles Éric Bouillé, 34, a former archeology student from Quebec.

Compared to other excavation sites, “it is the most particular, the hardest mentally vis-à-vis daily life, the way of life”, confirms Lina Guelouza, student in archeology at Paris-I Panthéon Sorbonne, who however says that he had “a crush on the island”.