High up in the Pyrenees Mountains, a cave holds the oldest evidence of intense human occupation in the region. But prehistoric people weren't just sheltering here; they were working, hunting for and processing a mysterious green mineral.
The discovery was made in Cova 338, a cave located around 2,235 meters (7,332 feet) above sea level in the Núria Valley in the Pyrenees Mountains of Spain. Archaeologists from the Autonomous University of Barcelona (UAB) and IPHES-CERCA found that the cave was a very active place for human activity for 4,000 years, from the 5th millennium BCE to the end of the 1st millennium BCE.
It was long assumed that high-altitude environments above 2,000 meters (6,561 feet), where the air is thin and conditions can be harsh, were only occasionally lived in, perhaps used only in desperate circumstances. However, Cova 338 suggests this wasn't always the case.
"Cova 338 forces us to rethink the role of high mountain environments in Pyrenean prehistoric societies," Carlos Tornero, professor in the Department of Prehistory at the UAB and researcher at IPHES-CERCA, said in a statement. "For a long time, these spaces were assumed to be unimportant. What we document here is repeated occupation, with complex activities and a clear use of mineral resources."
Inside the cave, the team dug up plant remains, ceramic fragments, and charcoal, which suggests humans lit fires here many thousands of years ago. They also recovered two beautiful pendants: one made from a sea shell (Glycymeris) and another from the tooth of a brown bear.
Striking as those objects are, the most intriguing find was what Tornero described as a "remarkable collection of green minerals, likely malachite, a copper-rich mineral." Nearly 200 rocky fragments containing patches of the green mineral were recovered from the cave floor. They were found alongside nearly 23 fireplaces, many of which contained burned specks of the green substance.
That small detail matters enormously. Malachite is known to be the ore that launched the Copper Age, and heating it with flames is how ancient metalworkers extracted the metal from rock. It seems very likely that people weren't merely sheltering or foraging up here in the cave; they were mining and smelting copper.
"Many of these fragments have been changed by heat, while other materials in the cave have not, which clearly suggests that fire played an important role in their processing and that there was a deliberate intention behind it. In other words, they weren't burned by accident," co-author Dr Julia Montes-Landa, from the University of Granada, said in another statement.
If that interpretation holds, Cova 338 would rank among the earliest known sites of copper mining and processing in Western Europe.
"For the first time in the Pyrenees, high-mountain prehistoric occupations of significant intensity have been documented, marked by repeated activities and the direct use of mineral resources within the cave," added Tornero. "This site shows that the Pyrenees were not an unimportant territory for prehistoric communities, but a space fully part of their movement and land-use strategies."
Reaching this site is no easy task, even in the 21st century. It's only reached on foot from the Núria Valley, without any motor vehicles. Everything the researchers collected had to be carried back down the mountain by hand, which makes the scale of ancient activity documented here all the more remarkable.
"The mountain was not a barrier, but an active place within the economic and territorial organization of prehistoric communities," added co-author Eudald Carbonell.
The study is published in the journal Frontiers in Environmental Archaeology.