Unravelling prehistoric fire use: ‘Variation in fire conditions equals variation in human behaviour’ – Leiden University
Heating conditions
Eighteen Upper Palaeolithic hearths from the popular site of Abri Pataud were evaluated. Abri Pataud is a rock shelter with a well-preserved sequence, located in the Southwest of France. ‘These ancient hearths include ashy material, highly fragmented charcoal, and heated bone,’ Femke Reidsma discusses. Using a mix of brand-new strategies and reference data, the scientists explore the remains’ clues on the application of the fire. ‘We can now evaluate the materials to get to the heating conditions of previous fires.’
A better understanding of these heating conditions might lead to a better understanding of the fire’s application. ‘We assume that fire temperature level can be connected to what individuals made with fire in the past. A variation in fire conditions equates to a variation in human behaviour.’ While Reidsma focused on developing analytical strategies on bone material, her colleague Freek Braadbaart explored charcoal. Other specialists examined molecular traces in the ashes and sediments. ‘As principal detective, Freek Braadbaart integrated the information to get a much better understanding of the heating conditions and preservation of the fireplaces. After Freek’s passing, with Wil Roebroeks I took control of this role, and after a lot of diggng through Freek’s files we had the ability to complete the paper together with the other authors.’
Molecular traces
It is frequently assumed that if things have been heated, that they stay the exact same indefinitely and protect effectively. This is not the case. Speculative work by both Braadbaart and Reidsma has actually shown that chemical weathering affects the method heated products preserve. ‘Understanding this, we clearly took the impact of diagenesis into account in our research study of the fireplaces of Abri Pataud. This helped us get to more precise interpretations of the heating conditions.’
The examination expanded, consisting of the research study of sedimentary DNA by coworkers from the MPI-EVA at Leipzig, to better understand the owners of the fireplaces. This led to the discover of the very first sedimentary DNA proof of early contemporary human beings. ‘We integrated macro and micro scale analysis, and released an entire series of analytical strategies to get to the most complete image.’
Searching for fuel
So what is the most total picture? ‘Generally a more complicated and nuanced photo of the fire. There were changes in heating temperature with time, for example, in between roughly 35 and 25,000 years back.’ In addition, most of the bone was discovered to be heated up indirectly. ‘For a long period of time people have actually assumed, based on the high portion of heated bone, that bone was used as fuel.’ According to this viewpoint, a deficiency of wood in the glacial world led to this development. ‘You need to understand that bone is a really inefficient fuel, due to its high inorganic material, and that it likewise makes no sense to hunt for your fuel. The most probable explanation is that the bones were found in a layer of haven of an earlier profession phase, that the fires were built on top of.’
Old dung
The charcoal analysis likewise provided new insights. ‘We discovered evidence for an alternative fuel in the charred natural material samples: microscopic pieces that look like dung.’ This would fit ethnographic precedence, as well as the scenarios of glacial epoch Europe. ‘If it holds true that there was inadequate wood, individuals could have utilized reindeer dung. We discovered only two or three pieces, so the proof is limited. Even so, it’s the earliest sign of dung utilized as fuel so far.’
Crowning work
Summing up, Reidsma concludes that the main takeaway of this approach is that it is the method forward. ‘By integrating the arise from different approaches and various materials we got a much clearer and complete picture than we would have gotten if we just looked at the charcoal or the bone. In regards to historical interpretations, we validated suspicions that were already there. The discovery of the dung and the debunking of the bone-as-fuel theory also have implications for other websites.’
Freek Braadbaart did not live to see the publication of this paper. ‘He regretfully passed away in December 2018. This paper is the crowning work on his research study, and I more than happy we had the ability to complete it for him. This paper really clearly reveals his vision on how you are expected to study fire use: holistically, integrating all techniques and materials.’
About the project
This research was conducted in partnership with colleagues from different institutes in the Netherlands, France, Germany and Spain (see the paper for the authors’affiliations).
The project was moneyed by the Koninklijke Nederlandse Akademie van Wetenschappen, Academy Teacher Reward program 2013, awarded to Wil Roebroeks.