Humans
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An ugly, misshapen blob of glassified soil could rewrite the story of humanity’s technological heritage, suggesting that we began experimenting with copper smelting while we were still hunter-gatherers. Dated to around 10,800 years ago, the greenish-yellow lump was discovered at a Pre-Pottery Neolithic site in Türkiye and shows signs of deliberate exposure to extremely high temperatures.
Exactly how metallurgy began remains something of a mystery, with some scholars believing that the practice took off at the same time as pottery, given that both disciplines require the use of specialized furnaces. To date, the oldest confirmed examples of copper metallurgy come from Belovode and Pločnik in Serbia and are dated to between 5350 and 4600 BCE.
However, in 2021, while excavating a site called Gre Filla in the Upper Tigris valley, researchers came across the strange vitrified lump in an area that had been identified as an ancient street. Recovered from a layer of sediment dated to almost 11,000 years ago, the enigmatic relic predates the Serbian artifacts by many millennia.
Analyzing the nugget, the authors of a new study note that an abundance of ash and charcoal deposits were found nearby, along with an assortment of animal bones. This indicates that cooking fires were probably lit on a routine basis within this part of the site, raising the possibility that copper within the soil may have accidentally been melted.
Yet a closer inspection suggested that this probably wasn’t the case. For instance, the researchers say the presence of “high-temperature mineral phases” suggests that the metal was exposed to extreme heat of around 1,000 °C (1,830 °F). Furthermore, “microstructural features” provide evidence that the copper underwent rapid cooling after being heated.
Moreover, the authors explain that “depression marks” on one side of the lump likely “correspond to the indentations caused by the inner surface of a furnace or kiln… reinforcing the idea that [the specimen] was exposed to high temperatures in a controlled environment.”
Despite this, though, no actual furnace was found anywhere near the vitrified object, making it impossible to positively identify the item as a product of deliberate smelting. So far, only one dome-shaped furnace has been discovered at Gre Filla, although it is located in a separate area of the site and its purpose remains unknown.
Just as importantly, no metallurgic by-products like slag have been recovered from the site. The presence of such waste would provide the smoking gun for copper smelting among this group of ancient Anatolian hunter-gatherers, yet its absence leaves the study authors wary of making any definitive claims.
“Although there is no direct evidence of full-scale metal smelting, the presence and distribution of copper droplets imply that copper-bearing material or native copper was exposed to high heat,” they write.
“The limited data indicate that rather than positioning Gre Fılla as a fully developed site for extractive metallurgy, it should be viewed as a location where key metallurgical principles – such as controlled heating, casting, and potential ore-processing – were being actively explored,” they conclude
The study has been published in the Journal of Archaeological Science: Reports.
