Heat alterations of flint artefacts: archaeological evidence, experiments and analyses

Abstract

Heat treatment of flint and other knappable materials has been recognized among prehistoric archaeological lithics, leading to a wide range of experiments and archaeometric analyses. The aim of these analyses was to shed light on the mechanical and chemical changes that occur in lithics (flints) subjected to heat treatment, some of which remain poorly understood.
This paper does not focus on intentional heat treatment of lithics in its technological aspect – for enhancing the debitage/flaking properties of the raw material. Our scientific goal was to record and document the various changes that occurred in different flint artefacts subjected to heat and to apply the observations to several well-illustrated case-studies of artefacts from archaeological contexts with recognizable stigmata of heat treatment. To achieve a better understanding of the factors and processes that produce alterations we used a range of analytical techniques: micropetrography, microstructural analysis [(powder X-Ray diffraction (XRD)] and Fourier-transform infrared spectroscopy (FTIR) with interesting results.