Fire and heat, from hearth to charcoal: An experimental approach to temperature in the context of Palaeolithic hearths

Abstract

Whether one is interested in palaeoeconomics or technical aspects of fire use, or in taphonomy, the concept of temperature plays a central role in charcoal analysis. What does the temperature reveal about the function of the hearths? Can prehistoric hearth temperatures be accurately measured a posteriori, and what information could be gleaned from such measurements? Changing scale, what are the effects of fire temperatures on the residues themselves in terms of taphonomy and what are the consequences for the preservation of isotopic and molecular signatures?

To address these questions, we conducted over two hundred experimental standardised combustions under laboratory conditions. Our results, supported by mathematical data processing, provide insight into the properties of wood combustion, including fragmentation processes. We also explored the challenges of measuring temperatures in both the combustion structures and the charcoal itself.

Our results show that temperatures in the open-air fireplaces are highly labile, with average temperatures always within the same range regardless of the taxa. We also provide information on the effect of temperature on fragmentation processes but also on the isotopic and molecular signature.