The enigma of the Neolithic population decline that impacted Northern Europe around 3100 BC has recently been clarified by a new scientific explanation. An innovative study has revealed that the significant population decrease in various regions allowed new demographic and cultural groups to occupy the territory.
These new populations migrated from the south, with Iberians beginning to repopulate the Paris Basin around 2900 BC. A mysterious void in the contents of a 5,000-year-old megalithic tomb located on the outskirts of Paris may elucidate not only this widespread population decline but also who repopulated the region. The Bury tomb, situated approximately 50 kilometers north of Paris, is a stone funerary monument containing the remains of about 300 people.
Through a combination of DNA and demographic analysis, researchers investigating the tomb believe they have discovered the reason why the Paris Basin underwent a dramatic population shift around 3100 BC, and who entered the region to take their place. A new study, published in the journal Nature Ecology & Evolution, links the Stone Age site in the Paris region to a massive demographic crisis that occurred across the continent. Before the enigmatic population decline, the construction of megalithic tombs characterized the vast area for over 1,000 years. Although each region had its own cultural peculiarities in funerary constructions, the tombs in Bury were consistent and communal, housing tens of thousands of burials over the centuries.
According to Popular Mechanics, the construction of these tombs abruptly ceased throughout northwestern continental Europe at the end of the fourth millennium BC. This interruption in the millennia-old funerary tradition occurred everywhere, and until now, the reason remained unknown.
The investigation of the Bury megalithic tomb revealed two distinct phases of burials: the first from approximately 3200 to 3100 BC, and the second starting around 2900 BC. The 200-year interval without burials coincided with a wave of population losses across Northern Europe, a Neolithic decline that researchers did not fully understand but contributed to a complete reshaping of populations in the area.
By analyzing DNA evidence from 132 individuals found in Bury, the team discovered that the two distinct historical phases were unrelated. Individuals from the first phase exhibited genetic diversity that extended well beyond the Paris Basin, linked to farming populations across the continent. In contrast, the burials of the second phase were substantially more homogeneous, with over 80% of the group’s ancestry traced back to Neolithic Iberia, a region corresponding to present-day Spain and southern France.
The burial styles were also different, with first-phase burials featuring multigenerational families and evidence of women marrying into the community from outside, while second-phase burials included smaller families and unrelated individuals buried close to each other. With distinct Y-chromosome lineages in the second phase, it is concluded that it was not a gradual cultural change, but a dramatic population replacement.
Combined with pollen data, indicating that forests were regenerating during the interval, and a shift in agricultural practices after the interval, the replacement signals the abandonment of pastures and fields, suggesting that settlements were empty. The pattern resembles what occurred after the Justinian Plague and the Black Death.
The authors argue that the decline of 3100 BC was geographically broad, creating a demographic vacuum across northwestern Europe that allowed neighboring populations to fill the void. In Scandinavia, steppe herders completely replaced local farmers. In the Paris Basin, Iberian farmers moved into the then-vacant spaces.
‘We can thus consider the possibility that both the northward Iberian migration and the steppe expansion were related responses to the Neolithic decline,’ the authors wrote, ‘since widespread demographic contraction would have created a vacuum that neighboring groups could expand into.’
The first community that defined the Paris Basin was essentially erased, but clues about what caused this erasure were found in the Bury tomb. Researchers discovered ancient pathogens, including plague and lice-borne relapsing fever, in the remains. Experts believe that infectious diseases, environmental stress, and demographic contraction led to widespread population collapse. ‘These findings detail a population replacement at the end of the fourth millennium BC,’ they wrote, ‘offering a possible explanation for the cessation of megalith construction.’
Original published at O Cafezinho.