The story of Le Tumulus des Sables burial mound starts out like a horror movie. In 2006, toddlers began tugging human bones out of their kindergarten playground in Saint-Laurent-Médoc, a town in the Bordeaux region of France. When authorities began to investigate, they determined the teeth and bones weren’t from some gruesome crime, but an archaeological site. Excavations eventually unearthed the jumbled remains of 20 adults and 10 children believed to be from the Bell-Beaker culture, an important early Bronze Age group that spread all over western and central Europe, leaving behind distinctive pieces of bell-shaped pottery.
But a new study of the remains shows something extraordinary: The mound was used by locals for 2,000 years, from about 3,600 B.C. to 1,250 B.C., well into the Iron Age.
Dyani Lewis at Cosmos reports researchers made the discovery after performing radiocarbon dating on eight teeth found at the site, seven from adults and one from a child. They also looked for four different isotopes, variations of carbon, nitrogen, strontium and oxygen, in a wider sample of teeth, which can reveal where people were born and the general outline of their diet. The results appear in The Journal of Archaeological Sciences: Reports.
The analysis reveals that six of the individuals date to the time of the Bell-Beaker culture, with one much older and one much younger, a span of 2,000 years. The isotopes revealed something unusual as well. The site is very close to the Gironde Estuary and the Dordogne and Garonne Rivers and just a few miles from the Atlantic Ocean. Yet, the isotope analysis reveals the inhabitants weren’t eating fish or seafood. Over the course of those 2,000 years, the people relied mainly on food from the land.
Lewis reports that, unlike other Bell-Beaker sites, where up to two-thirds of inhabitants appear to come from outside the region, the isotopes indicate only one person in the burial mound comes from elsewhere, most likely a colder climate to the south, like the Pyrenees mountains. The isotopes indicate the other people in the mound were sedentary, with almost all of them growing up in the immediate area. The team also found baby teeth and teeth without full roots, indicating children born in the area were included in the burial.
The most vexing question is why was this particular fairly nondescript burial mound was used for thousands of years. “It’s unusual because it’s not really obvious or prestigious,” Hannah James, graduate student at the Australian National University and lead author of the study says in a press release. “It’s a mound about 50 cm [1.6 feet] deep. It’s not on a hill or an obvious location, so there’s something else about this site which caused people to come back and use it.”
It’s possible that some answers are still to come from the remains. which were small and fragmentary, jumbled up with pottery, animal bones, bits of metal and other grave goods. It’s possible that more than 30 people were buried in the mound.
The study may also help solve some mysteries about the Bell-Beaker culture. Researchers have debated whether the appearance of the distinctive bell-shaped pottery across Europe was just part of a cultural exchange in which various groups adapted the new style of vessel, or whether it indicates that a separate group of people actually invaded and spread across the continent. Recent research suggests a bit of both, reports Ewen Callaway at Nature. While DNA from sites in mainland Europe indicate it Beaker culture was primarily a spread of ideas, in Britain genetic analysis indicates that Neolithic farmers on the island were displaced by an invading group of Beaker folk.