Enigmatic Green Stones Uncovered in an Isolated Cavern in Spain Could Indicate Prehistoric Humans Engaging with Copper

The discovery challenges the belief that ancient inhabitants of the region spent minimal time at elevated elevations.

Reaching Cave 338, situated high in the Pyrenees mountains, requires traveling mostly on foot. This is precisely the approach a team of archaeologists took during a recent dig—and likely mirrors what ancient peoples did thousands of years ago when the location may have been utilized for copper processing.

A recent study published in Frontiers in Environmental Archaeology uncovered hearths, jewelry, children’s remains, and a green mineral believed to be malachite, a key copper source.

Historically, archaeologists assumed that prehistoric groups in that area seldom occupied high altitudes. However, this newfound evidence contradicts that belief.

“Cova 338 compels us to reconsider the significance of high-altitude environments in the prehistoric societies of the Pyrenees,” states Carlos Tornero, the study’s primary author and a researcher at the Catalan Institute of Human Palaeoecology and Social Evolution, in a university statement. “For an extended period, these areas were regarded as marginal. What we illustrate here is frequent occupation, with intricate activities and clear mineral resource utilization.”

Between the Stone Age and the Bronze Age lay a transitional phase during which humans began to manipulate copper. The material was highly valued for its malleability, corrosion resistance, and excellent thermal conductivity. By the mid-fourth millennium B.C.E., Mesopotamians were utilizing copper to construct tools and weapons. By 3,000 B.C.E., Neolithic societies in Europe began using copper as well. During this evolution, people discovered the combination of copper with tin resulted in bronze.

The archaeologists identified four distinct strata within the Spanish cave that represent different human visitation periods. The oldest layers contained only charcoal, while the most recent ones were quite thin; however, the two intermediate layers, dating from 5,500 to 3,000 years ago, encompassed several hearths with charred remnants possibly linked to malachite.

Malachite is not indigenous to the cave, leading archaeologists to theorize that prehistoric individuals may have transported it up the mountain for processing, according to reports by Kristina Killgrove in Live Science.

“Numerous fragments exhibit thermal alteration, while other materials in the cave do not, indicating that fire was significantly involved in their processing and that there was a conscious intention behind it,” claims Julia Montes-Landa, co-author and archaeologist at the University of Granada in Spain, in a statement released by Frontiers. “In essence, they were not subjected to fire by chance.”

There are several potential reasons why prehistoric populations might have ventured to such altitudes for copper production, as ZME Science’s Mihai Andrei reports. It’s conceivable that the cave offered greater protection due to its elevation or that mineral extraction sites were readily available, although the team has yet to unearth a nearby mining locale.

Evidence from the dating of the artifacts suggests that the cave was not a constant habitation but that prehistoric groups frequented it regularly for brief intervals between the fifth millennium B.C.E. and the conclusion of the first millennium B.C.E. The discovery of children’s remains may also imply that the cave functioned as a burial or ceremonial site.

“This location illustrates that the Pyrenees were not a peripheral area for prehistoric communities but rather a space intricately woven into their mobility plans and territorial resource management,” Tornero notes in the university statement.

Archaeologists plan to continue their investigations at Cave 338 and are actively working to verify the identity of the green mineral.