This Is How Humans Managed to Make Fire During the Ice Age Glaciation

For millennia, fire has been considered an essential element for human survival: it not only provided warmth in hostile climates but also enabled food cooking, tool-making, and even served as a hub for social interactions. In the context of the European Ice Age, this resource must undoubtedly have been a vital pillar for hunter-gatherer groups facing extreme temperatures.

However, one aspect has puzzled the scientific community for decades: the scarcity of well-preserved archaeological evidence proving the use of fire during the coldest period of this glacial cycle, known as the Last Glacial Maximum, which occurred between 26,500 and 19,000 years ago.

Faced with this enigma, an interdisciplinary team of researchers led by the University of the Algarve (Portugal) and the University of Vienna (Austria) has managed to provide valuable information that helps reconstruct the behavior of our ancestors during that critical stage. At the prehistoric site of Korman’ 9, located on the banks of the Dniester River in present-day Ukraine, scientists have identified and analyzed three hearth structures that offer clues about the use of fire by Homo sapiens in the very heart of the glaciation. The results of this study were recently published in the journal Geoarchaeology.

ukraine fire stone age glaciation ice — (A) Geological map of the Middle Dniester Valley with Korman’ 9 highlighted.(B) Site location on the Dniester River with the trenches and sections highlighted. (C) Digital elevation model for Korman’9 site. The locations of the combustion features are indicated by stars. Credit: W.C. Murphree & P.R. Nigst

Thanks to a combination of advanced geoarchaeological techniques — such as microstratigraphic analysis, sediment micromorphology, and colorimetry — the team was able to characterize three flat hearths, seemingly simple, but whose technological complexity reveals a much more sophisticated fire management than previously assumed for that time. The temperatures reached in these structures exceeded 600 °C, which constitutes clear evidence of detailed pyrotechnic knowledge even under extreme environmental conditions.

One of the most notable findings is that the main fuel source used was wood, specifically fir, according to charcoal analysis. However, the complementary use of other combustible materials such as animal fat or bones is not ruled out. In fact, some bone remains found at the site show signs of having been subjected to temperatures above 650 °C. According to Marjolein D. Bosch — zooarchaeologist affiliated with the University of Vienna, the Austrian Academy of Sciences, and the Natural History Museum of Vienna — the team is still investigating whether these bones were intentionally used as fuel or if they were simply accidentally incinerated during hearth use.

Although the three identified structures share an open and flat shape, the differences among them suggest variations in their construction and use, possibly related to seasonal changes. One of the hearths, larger and with thicker residue layers, might have been used to generate more intense or prolonged heat. According to Philip R. Nigst, archaeologist at the University of Vienna and co-author of the study, these details indicate that Upper Paleolithic populations not only mastered fire, but knew how to adapt it to different purposes, both functional and social, and may even have reused the same spaces at different times of the year during their cyclical migrations.

Despite the relevance of these findings, the widespread scarcity of evidence for fire use at other sites corresponding to the Last Glacial Maximum remains a subject of debate. William Murphree, geoarchaeologist at the University of the Algarve and lead author of the study, raises key questions: Could the freeze-thaw cycles characteristic of the soil at that time have destroyed most hearth remains? Was the lack of fuel resources an impediment? Or were alternative technological solutions used instead of traditional burning?

Beyond answering these specific questions, the team of researchers aims to contribute to a broader understanding of the role that fire mastery played in human evolution. As they emphasize in their publication, fire was not only a practical tool but one of the most fundamental technological advances for the expansion of our species across diverse environments on the planet.

The investigations carried out at Korman’ 9, which included deep excavations under more than two and a half meters of loess sediment, have shown that even in the most adverse periods of prehistory, human groups not only survived but did so through complex adaptive strategies, of which fire management was undoubtedly a key element. Thus, each new trace of ash, each charred remain, or each thermal structure discovered becomes a window into human ingenuity in remote and hostile times and contributes to unraveling the mechanisms that made our persistence as a species possible.

SOURCES

Universität Wien Murphree, W.C., Ferro-Vázquez, C., et al., (2025), Fire Use During the Last Glacial Maximum: Evidence From the Epigravettian at Korman’ 9, Middle Dniester Valley, Ukraine. Geoarchaeology, 40: e70006. doi.org/10.1002/gea.70006