Burning flint: An experimental approach to study the effect of fire on flint tools

Burnt lithic artefacts are regularly discarded from microwear analyses, causing a bias in the functional interpretation of prehistoric sites. This is especially true when burnt lithics are numerous as is typically the case on Mesolithic sites in Northern Belgium. Burnt stone artefacts potentially hold information regarding the functional, spatial, and social organisation of the site. Therefore, investigating the impact of burning on lithic tools, and especially on the preservation of microwear traces is crucial. In this paper, we present the experimental approach developed to tackle this problem. Flint tool replicas were burnt in several open fire experiments, organised to reproduce conditions that were realistic to those of the original prehistoric contexts. This way, we could evaluate the impact of different fuel types on the longevity and intensity of the fire. These experiments provide essential information on the effects of heat on the physical aspects of flint artefacts. Therefore, the relation between raw material characteristics and the degree of burning is studied as well. In addition, the results of the open fire experiments could be related to the spatial distribution of burnt flints in surface hearths. The findings are interpreted on a socio-economical level in order to better understand how and why lithics could have ended up in fire.