Building an Experimental Comparative Reference Collection for Lithic Micro-Residue Analysis Based on a Multi-Analytical Approach

Residue analysis applied to stone tools is a useful aid for better understanding their past function and, by extension, reconstructing early human behaviour. However, if the nature of residues found on the lithic tools is misinterpreted, so will be our understanding of their archaeological context. As a consequence, correctly identifying residues in the domain of lithic studies is of paramount importance. With this main goal in mind, we analysed different experimental materials likely to have been involved in daily tasks in the prehistoric context (e.g. bone, wood, meat). Microscopic analyses were then carried out using two (comparable) techniques: Optical Light Microscopy and Scanning Electron Microscopy. Also, energy dispersive X-rays spectroscopy (EDX or EDS) was applied to the experimental samples to determine their elemental composition. Advantages and disadvantages of both microscopic methods and their implications for correct residue identification are discussed. The distribution of residues on lithic surfaces is also considered. This study resulted in the construction of a data-set including both photographic material and EDX spectra for each residue analysed. The main result is that, compared to OLM scanning, SEM analyses highly improves the accuracy of residue identification.