Researchers on the Danish island of Bornholm found a connection between ancient volcanic eruptions and prehistoric rituals involving sun stones. These engraved stone plaques appear to have been sacrificed by Stone Age people in response to a volcanic eruption around 2,900 BCE, according to recent studies by the University of Copenhagen and the Museum of Bornholm.
The sun stones, found at the Vasagård archaeological site, are flat pieces of slate engraved with patterns and motifs representing the sun and fertility. Between 2013 and 2018, archaeologists discovered large numbers of these artifacts, totaling 614 plaques and fragments. These stones were deposited en masse in ditches that formed part of a ceremonial enclosure, indicating a ritual event.
Archaeologists believe that these rituals were a response to climate disasters triggered by a volcanic eruption that darkened the skies over Northern Europe. The eruption released large quantities of sulfur into the atmosphere, leading to a cooling effect that reduced sunlight and impacted agricultural yields. This had dramatic consequences for human societies, as evidenced by the ritual offerings made by Neolithic peoples.
"The cooling effect caused by the eruption reduced sunlight and impacted agricultural yields, which had dramatic consequences for human societies," according to Nature World News. The sun was essential for guaranteeing good harvests and was crucial for early agricultural cultures in Northern Europe. The volcanic eruption around 2,900 BCE was a catastrophe for their ability to grow crops.
The sun stones were discovered in ditches about 4,900 years old, covered by a stone pavement that contained fragments of pottery and other objects typical of the culture present in the region until about 2,900 to 2,800 BCE, according to SciencePost. The vast majority of the solar stones were made from black shale, a dark, layered sedimentary rock present on the island. Some of the stones were also made of quartz and flint.
The first discovery of these solar stones occurred in 1995 when a few fragments were unearthed during excavations at the Neolithic site of Rispebjerg on Bornholm. Since then, hundreds of these artifacts have been found, offering a glimpse into one of Scandinavia's earliest known sun-worshiping cultures.
"They symbolized fertility and were probably sacrificed to ensure the Sun and growth," explained Rune Iversen from the University of Copenhagen, co-author of the study and participant in the excavations, as reported by SciencePost. The sun stones were engraved with incised patterns, including representations of the sun and plants, and were offered to ensure the return of the sun and promote growth.
The researchers believe there is a connection between the sun stone offerings, the volcanic eruption, and subsequent climate changes. High concentrations of sulfates detected in ice cores from Greenland and Antarctica during this period indicate that the eruption likely occurred near the equator and had widespread repercussions. Sulfates are compounds commonly found after a major volcanic eruption.
Ash clouds from the eruption could have obscured the sun and led to a drop in temperatures for several years. This severe cooling around 2,900 BCE is corroborated by other sources, including tree rings preserved in the Main Valley in Germany and those of Bristlecone pines in the western United States. "If the sun was partially disappearing due to prolonged stratospheric haze, that would have been extremely frightening for them," Iversen said, according to SciencePost.
"Without harvest, without seeds for the next year, they must have felt deeply punished, like caught in an endless catastrophe," Iversen noted. The clues on the site suggest that these stones were deposited over a short period, perhaps in a single event, around 2,900 BCE. "Why did they deposit all these artifacts at the same time?" asked a researcher, according to SciencePost.
"Following the sunstone sacrifices, ceremonial enclosures were modified with palisades and cult houses, reflecting a shift in cultural practices," Nature World News reported. This suggests that in response to the upheavals caused by the volcanic eruption, Bornholm's Neolithic people adapted their rituals and structures, as evidenced by changes in their gathering places.
The combination of environmental and health crises likely influenced the decline of the Funnel Beaker Culture, a dominant Neolithic society known for its pottery and passage graves. Alongside climate change, DNA analysis of human remains from the same period points to widespread outbreaks of the plague, indicating that Neolithic peoples of Northern Europe faced similar trials despite the lack of written sources.
Copenhagen University stated in a press release, that these findings were made in collaboration with climate researchers from the Niels Bohr Institute. "It is reasonable to believe that the violent changes they have been subjected to must play a role in some way," said Iversen.
"This discovery demonstrates the ingenuity and resilience of ancient societies in the face of adversity," Iversen said.
Four sunstones from Vasagård are on display at the National Museum of Denmark, offering a glimpse into one of Scandinavia's earliest known sun-worshiping cultures.