The Role of Fire in the Life of an Adhesive

The use of fire is essential for the preparation of hafting adhesives; both are suggested to be a proxy for distinguishing the technological expertise and complex cognition among Palaeolithic populations. While use of fire has been argued to exist from about 1.0 Ma onwards, evidence for adhesives in the Palaeolithic record is rare and fragmented. In spite of the close link between fire places and adhesives, no study has ever focussed on examining the impact of heat on adhesive deposition and preservation. This paper discusses the results of a combustion experiment that was undertaken to understand the impact of heat exposure on hafting adhesives. The results have significant implications for archaeological interpretations. Deposition in or near a fire proves to severely impact the types of residues that preserve on a stone tool. The vertically transferred heat is responsible for the loss of adhesives but also for the incidental production of adhesives and their deposition on stone tools. It can be hypothesised that the rare survival of adhesives on archaeological stone tools might not only be the result of direct contact with the fire but also the result of degradation due to heat from overlying fireplaces. If we are to improve our understanding of the preservation of adhesives, it is important to unstand the taphonomic processes that affect these adhesives, in particular heat alteration.