Sandstone ground stone technology: a multi-level use wear and residue approach to investigate the function of pounding and grinding tools

Ground stone tool (GST) technology includes artefacts utilized in pounding or grinding activities and characterized by long life cycles and multiple uses. The introduction of such technology dates back to early prehistory, and for this reason, it is used as prime evidence for tackling a wide range of archaeological questions such as the origins of technology, patterns of daily subsistence and lifeways. In this paper, we contribute to the field of study of GSTs by discussing the application of a novel multi-level analytical approach combining use wear and residue observations at low and high magnification with residue spatial distribution investigated using GIS. We aim to assess the potential of a combined use wear and residue approach to (1) discriminate specific gestures and worked materials on sandstone GSTs and (2) understand the potential of residue distributions for reconstructing ancient GST functions and, more specifically, the role of GSTs recovered at Mesolithic sites of the Danube Gorges region in the Central Balkans. We identified diagnostic surface modifications associated with the use of GSTs in different activities involving both animal and plant materials. Morphological characteristics of residues have been described under reflected and transmitted light and characterized using biochemical staining. Finally, we mapped residues across the utilized surfaces of experimental tools to link patterns of residue spatial distribution to specific materials and gestures. We expect our methodological approach will be taken up by other researchers in order to produce comparable datasets on GSTs and improve our understanding of their ancient functional biographies.