High in the eastern Pyrenees, archaeologists have discovered evidence that could change our understanding of how prehistoric people used mountainous landscapes. A cave located more than 7,300 feet (2,235 m) above sea level contains dozens of ancient hearths filled with green mineral fragments that may point to early copper mining activities.
Discoveries suggest that people visited this remote location repeatedly over a period of approximately 2,000 years. The findings challenge the long-held belief that prehistoric communities moved through high-altitude environments only for short periods of time. Researchers also recovered a child’s finger bone and a baby’s tooth, raising the possibility that the cave may have served as a burial site.
“For a long time, high-mountain environments were seen as marginal, where prehistoric communities occasionally passed through,” said Professor Carlos Tornero of the Catalan Institute of Human Paleoecology and Social Evolution, lead author of the article. Frontiers in Environmental Archeology. “But we found a really rich archaeological sequence, including many combustion structures and a very large number of green mineral fragments. We can’t say how long people stayed each time, but the repeated use of the site and the density of remains suggests occupations that were short to medium term, but recurring over longer periods.”
Ancient hearths and possible copper mining
This site, known as Cave 338, is located in the Fraser Valley. Archaeologists excavated a 6-square-metre area near the cave entrance and identified four distinct layers of human activity.
The most recent layer was relatively thin and contained very few artifacts from the historic period, suggesting that the cave had limited use during that time. The deepest and oldest layer contained only charcoal fragments, dating back about 6,000 years.
The most important discoveries came from the second and third layers. Researchers discovered 23 hearths that contained large numbers of crushed and burnt pieces of the green mineral. Detailed testing is still ongoing, but the material resembles malachite, a copper-containing mineral that can be processed to produce copper.
If confirmed, the evidence may indicate that Cave 338 served as a surprisingly early high-altitude mining camp.
“Many of these pieces have been thermally altered, while other materials in the cave have not been altered, which clearly suggests that fire played an important role in their processing and that there was a deliberate intention behind it,” said co-author Dr. Julia Montes-Landa of the University of Granada. “In other words, they didn’t burn accidentally.”
Hearths often overlapped each other, suggesting that the same area was reused repeatedly. Also, individual hearths remain clearly distinct, indicating that the trips were separated by a substantial period of time rather than representing a single continuous occupation.
Radiocarbon dating shows that the hearth is about 3,000 years older than the second layer. Hearths in the third layer date back to about 5,500 to 4,000 years ago.
Child remains and prehistoric jewelery
Researchers also recovered human remains from the third layer, including the finger bone of at least one child and the tooth of a child who was approximately 11 years old. Although there is currently not enough evidence to determine the cause of death or whether the two bones belonged to the same child, the discovery raises the possibility that additional burials may be hidden deeper within the cave.
Other artifacts provide clues about the people who visited the site.
“We recovered two pendants: one made of seashell and the other of a brown bear’s tooth,” Tornero said. “They come from prehistoric contexts, probably around the second millennium BC. The shell pendant is interesting because it has parallels in other sites in Catalonia, suggesting shared traditions or relations between different communities. The bear tooth pendant is much less common. It may point to something more specific or symbolic, possibly linked to the local environment.”
A cave revisited over thousands of years
Although Cave 338 was not used as a permanent settlement, repeated observations over the millennia suggest that the site was of significant importance to prehistoric groups.
Researchers hope that future excavations will reveal more about how the cave was used and when people occupied it. They also aim to determine the exact identity of the green mineral and trace its origin.
“The identification of the green mineral as malachite is still preliminary,” Tornero said. “Ongoing research by the University of Granada and the Autonomous University of Barcelona will provide final answers shortly. Furthermore, excavations have not yet reached the full depth of the site, so the sequence is not fully documented. This summer we will continue archaeological work.”