They say that when there is smoke, fires are lit, and researchers from the Weizmann Institute of Science are working hard to investigate the allegations, or at least clarify the meaning of “smoke.” In an article published on PNAS, scientists point out an advanced, innovative method they have developed and used to discover traces of invisible fire dating back at least 800,000 years – one of the first known proofs of fire use. The newly developed method may provide further scientific inspiration, a form of data-driven archeology, but – perhaps more importantly – it can help us better understand the origin of human story, our basic cultures and our exploration and innovation nature.
The controlled use of fire by the ancient hominin – a group that includes humans and other members of our deceased family – is thought to date back to at least a million years, at a time when archaeologists believe that Homo habilis began to evolve into Homo erectus. . That is not just a coincidence, as the practical theory, called the “cooking hypothesis,” is that the use of fire contributed to our evolution, not only allowing hominins to stay warm, making advanced tools and avoiding predators but also gaining the ability to cook . Cooking meat not only eliminates germs but increases effective protein digestion and the amount of healthy food, which opens the way for brain growth. The only problem with this view is the lack of data: since the discovery of archaeological evidence for pyrotechnology largely depends on the visual identification of changes caused by combustion (especially, color change), traditional methods have been able to obtain widespread evidence of fire use. no more than 200,000 years. Although there is some evidence of fire from 500,000 years ago, it is still relatively small, only five archaeological sites worldwide provide reliable evidence of ancient fire.
“We may have just finished sixth place,” said Dr. Filipe Natalio of Weizmann’s Department of Plant and Environmental Sciences, his previous collaboration with Drs. IdoAzuri, of Weizmann’s Department of Health Resources, and colleagues provided the foundation for this work. Together they pioneered the use of AI and spectroscopy in archeology to obtain evidence of controlled burning of stone tools dating back to between 200,000 and 420,000 years ago in Israel. Now that they are back, they are joined by PhD student Zane Stepka, Dr. LioraKolskaHorwitz of the Hebrew University of Jerusalem and Prof. Michael Chazan of the University of Toronto, Canada. The team went further by taking a “fishing trip” – diving away from the water and seeing what they could get back to. “When we started the project,” said Natalio, “archaeologists were analyzing the findings. Evron Quarry told us we could not find anything. We should have bet.”
Evron Quarry, found in West Galilee, is an open archaeological site that was first discovered in the mid-1970s. During a series of excavations that took place at the time and led by Professor Avraham Ronen, archaeologists excavated 14 meters and discovered a large series of animal fossils and Paleolithic tools dating back to between 800,000 and 1 million years ago, making it one of the oldest sites in Israel. None of the findings in the area or on the ground have any evidence of heat: ash and coal decay over time, eliminating the possibility of finding evidence of burns. So if Weizmann’s scientists wanted to find evidence of fire, they had to look far.
The “fishing” journey began with the development of a more sophisticated AI model than their predecessor. “We have explored a variety of methods, among which are traditional methods of data analysis, machine modeling and in-depth learning models,” said Azuri, who is in charge of model development. “The in-depth learning models available had some unique features and gave us the confidence we needed to continue using this tool in the context of archeology with no visible signs of fire use.” The advantage of AI is that it can find hidden patterns between multiple scales. By identifying the chemical composition of objects up to the cellular level, the output of the model can measure the temperature at which the stone tools were burned, ultimately providing information about past human behavior.
With the precise AI method in hand, the team can begin to capture cellular signals from stone tools used by Evron Quarry residents nearly a million years ago. To date, the team has tested the temperature sensitivity of 26 Flint tools available on site nearly half a century ago. The results showed that the equipment was heated at a wide range of temperatures – some exceeding 600 ° C. In addition, using a different spectroscopic method, they analyzed 87 animal fossils and found that the extinct elephant tusk also showed changes in thermal structure. Although cautious in their application, the presence of hidden heat indicates that our ancient ancestors, unlike the scientists themselves, were experimental researchers.
According to a team of researchers, by looking at archeology from a different perspective, using new tools, we can discover more than we originally thought. The methods they have developed can be used, for example, in other Lower Paleolithic sites to identify unseen evidence of fire use. In addition, this approach may provide a revitalized spatiotemporal perspective on the origin and controlled use of fire, helping us to better understand how hominin-related pyrotechnology evolved and led to other behaviors. Stepka states: “Especially in the case of premature fire, if we use this method in archeology at a million or two years old, we may learn something new.” With all the details, the fishing trip was an amazing success. Says Natalo: “It was not just a demonstration of experimentation and reward in terms of acquired knowledge, but the power of complacency: Ido has a field of quantum chemistry, Zane is a scientific archaeologist, and Liora and Michael are prehistoric experts. By working together, we have learned from each other. To me, it is a demonstration of how scientific research into all humanity and science should work. “
Source Journal Reference: Zane Stepka, Ido Azuri, Liora Kolska Horwitz, Michael Chazan, Filipe Natalio. Hidden signatures of early fire at Evron Quarry (1.0 to 0.8 Mya). Proceedings of the National Academy of Sciences, 2022; 119 (25) DOI: 10.1073/pnas.2123439119
