Prehistoric people in the eastern Pyrenees Mountains spent far more time at high altitudes than archaeologists previously expected, according to new research on a possible 6,000-year-old copper mining site in the region.
Discovered in this ancient high-altitude cave were fragments of green rock within ancient hearths, intriguingly co-located with human skeletal remains, indicating the site was used not just for seasonal work but also for permanent burial.
The discovery, revealed in a recent paper published in Frontiers in Environmental Archaeology, challenges archaeologists’ assumptions about high-altitude living in the prehistoric past.
Rethinking Prehistoric Life
The site in question, designated Cave 338, is located in the Fraser Valley some 2,235 meters above sea level.
“For a long time, high-mountain environments were seen as marginal, places prehistoric communities passed through occasionally,” said lead author Prof Carlos Tornero of the Catalan Institute of Human Paleoecology and Social Evolution. “But we found a really rich archaeological sequence, including multiple combustion structures and a very large number of green mineral fragments.”
While the current level of evidence leaves the exact duration of these prehistoric people’s stay at such an altitude uncertain, the density of the discoveries and the clear repeated use of the site suggest short to medium-term stays, according to the archaeologists.
After excavating 6.2 meters of area at the cave entrance, the research team has identified four distinct layers of prehistoric occupation at Cave 338. The fourth and most recent layer contained some materials that extended into historical times, yet this was clearly a period of infrequent use, as evidenced by its thinness.
The most ancient layer at the site, estimated to be 6,000 years old, showed the earliest human occupation, leaving only charcoal fragments.
Prehistoric Mining Discovered
Sandwiched between these layers of limited remains were the second and third layers, which evidenced periods of high use for relatively advanced purposes. Here, they uncovered 23 hearths, each containing curious green rocks, still under analysis. The team’s leading theory is that these green rocks are malachite used in copper production, which would make Cave 338 a high-altitude mining camp, well in advance of any expected timelines.
“Many of these fragments are thermally altered, while other materials in the cave are not, which clearly suggests that fire played an important role in their processing and that there was a deliberate intention behind it,” said Dr. Julia Montes-Landa of the University of Granada, one of the study’s co-authors. “In other words, they weren’t burned by accident.”
Radiocarbon dating places the second layer at 3,000 years old, and the third layer at between 4,000 and 5,500 years old. Since the hearths cut across one another, the archaeologists interpret the space as having been frequently reused for mining, though separated by long pauses.
Human Remains in Cave 338
It was in the third layer that human remains were recovered, including a finger and a tooth from a juvenile estimated to have been 11 years old. Unfortunately, concrete identification that both pieces of remains belong to the same individual is currently impossible, although the team suggests that more burials may be recovered as they excavate deeper into the cave.
Within the second layer, jewelry provided additional clues, and the archaeologists also discovered two pendants in the cave—one made from a bear tooth, and the other from a seashell, with the seashell pendant notably similar to pieces discovered in Catalonia.
While the researchers aren’t suggesting that these ancient people lived year-round at Cave 338, their findings do suggest that they spent far more time at this altitude than would have been expected.
“The identification of the green mineral as malachite is still preliminary,” concluded Tornero. “The research ongoing by the University of Granada and the Autonomous University of Barcelona will provide final answers shortly. Also, the excavation hasn’t yet reached the full depth of the site, so the sequence is not completely documented.”
“This summer we will continue the archaeological work,” Tornero said.
The paper, “Beyond 2000 meters, First Evidence of Intense Prehistoric Occupation in the Pyrenees,” appeared in Frontiers in Environmental Archaeology on May 5, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.