Scholars generally agree that fire was crucial to human survival during the most recent Ice Age—yet in Europe, there is surprisingly little evidence of hearths from its coldest years, between 26,500 and 19,000 years ago.
By studying three prehistoric hearths in Ukraine, a team of researchers has gained new insight into how fire was used during the Ice Age’s harshest period. As detailed in a study published earlier this month in the journal Geoarchaeology, the bygone fires reveal hints of sophisticated pyrotechnology, including the potential use of bones and fat for fuel.
“Fire was not just about keeping warm; it was also essential for cooking, making tools and for social gatherings,” Philip R. Nigst, one of the lead authors of the study and an archaeologist at the University of Vienna, said in a university statement. Although the archaeological record confirms that hunter-gatherers in Europe built fires throughout the Upper Paleolithic period (45,000 to 10,000 years ago), there is a roughly 7,500-year gap that coincides with the Ice Age’s coldest years.
“We know that fire was widespread before and after this period, but there is little evidence from the height of the Ice Age,” said William Murphree, another lead author and a geoarchaeologist at the University of Algarve.
Now, new evidence from Ukraine is helping to fill that gap. Researchers have investigated three ancient hearths dating back to the heart of the Last Glacial Maximum. The ancient hearths, excavated in 2013 at the Korman’ 9 archaeological site, date to between 23,000 and 21,000 years ago, and offer a rare glimpse into how Ice Age peoples used fire when it was needed most.
The scientists used geoarchaeological methods such as microstratigraphic analysis (a technique to study geographical layers in high resolution), micromorphology (the study of soil and sediment at the microscopic level) and colorimetric analysis (a technique to detect chemical compounds).
The analyses revealed that the fires reached over 1,112 degrees Fahrenheit (600 degrees Celsius), suggesting that European hunter-gatherers had a deep knowledge of fire building (hotter flames indicate more efficient combustion). While all three fires were open and flat, the researchers suggest they were intentionally built and used differently depending on the season. For example, one hearth was larger and thicker—likely the one that reached the highest temperatures.
“People perfectly controlled the fire and knew how to use it in different ways, depending on the purpose of the fire. But our results also show that these hunter-gatherers used the same place at different times of the year during their annual migrations,” Nigst explained.
While the researchers’ work indicates that the fires were mostly fueled by spruce wood, “some of the animal bones found at the site were burnt in a fire with a temperature of over 650 degrees Celsius,” explained Marjolein D. Bosch, a study co-author and zooarchaeologist at the University of Vienna. If confirmed, the use of animal bones and fats as fuel would suggest an even higher level of pyrotechnic expertise than previously assumed. “We are currently investigating whether they were used as fuel or just accidentally burned,” Bosch added.
The research sheds light on one of the first and most important technologies humans ever developed. Three prehistoric hearths, however, are not enough to close the vexing gap in the archaeological record, and so the mystery of pyrotechnology during the Ice Age’s peak remains unsolved.
