When a volcano erupted some 4,900 years ago, it devastated communities in the Northern Hemisphere. The eruption covered the sky and sent parts of the planet into a temporary cooling phase. Now, researchers believe hundreds of mysterious “sunstones” might be linked to this event.

The sunstones, unearthed in Denmark, may have been part of a ceremony to end the volcanic winter and bring back the Sun.

Magic sunstones

The archeologists uncovered 600 intricately engraved stone plaques on the Danish island of Bornholm. Bornholm, a small island in the Baltic Sea, holds two notable Neolithic sites: Vasagård and Rispebjerg. Both have large palisaded settlements and both were active during the Funnel Beaker culture, which flourished across northern Europe during the late Neolithic period.

The engraved stones were found in Vasagård West, buried in a distinct layer of soil corresponding to 2900 BCE. Whoever made the stones deposited them over a short period of time, possibly a year or a few years. They deposited them in a specific fashion, inside circular structures. This is a hallmark of ritualistic activity, but what ritual?

To get more clues, a team of researchers first analyzed the artifacts themselves. The stones, primarily crafted from local shale, feature geometric patterns, radial designs, and abstract imagery. The archaeologists dubbed them “sunstones” because of the motifs featured on them that resemble solar rays. They showcase intricate craftsmanship and were made with care.

These stones don’t seem like mere decorations. Obviously, there must have been a reason for depositing so many carefully crafted artifacts in a short span of time. But what was it? To get to the bottom of things, the researchers looked to a different source of information: ice cores from Greenland and Antarctica.

Traces of a disaster

Ice cores preserve information about past climates by trapping layers of snow and ice that accumulate over thousands of years. Each layer representing a specific period. Tiny air bubbles trapped within the ice contain ancient atmospheric gases, such as carbon dioxide and methane, while the ice itself captures isotopic ratios of oxygen and hydrogen, which offer clues about historical temperatures.

Volcanic eruptions leave distinct chemical signatures, such as spikes in sulfate and ash particles, embedded within the layers, allowing scientists to pinpoint the timing and scale of these events. These features make ice cores invaluable for reconstructing detailed records of past environmental changes, such as those that impacted the Neolithic communities of Bornholm.

In this case, the timeline fits. The ice cores show that around the time the sunstones were deposited, significant volcanic activity hit the Northern Hemisphere.

Still more questions linger

This supports the ritual theory very well. The society may have felt punished or tested by a deity associated with the Sun and tried to do a ritual to tame it and make things better.

But there are also significant questions. Most importantly, why didn’t people in the same culture in other areas try to do the same thing? It could be that other areas didn’t have access to resources (slate) to carve in, but they could have used other materials. It could also be that we simply haven’t found other similar caches or that there were cultural differences between different settlements.

If the sunstones were indeed meant to ward off the volcanic winter, they offer a poignant reminder of humanity’s trying relationship with the natural world. The reliance on agriculture made ancient societies acutely aware of shifts in weather patterns, which could spell abundance or disaster. In modern times, we seem to have detached ourselves from that. As we grapple with our own environmental challenges, the sun stones stand as a testament to the resilience of ancient peoples in the face of adversity.

The study has been published in the journal Antiquity.