The application of 3D modeling and spatial analysis in the study of groundstones used in wild plants processing

In recent years, several works have proved the reliability of the application of 3D modeling and spatial analysis in the study of stone tool use. Monitoring surface morphometry resulting from the use of lithic tools has the potential to objectively quantify and identify patterns of modifications associated to specific activities and worked materials. In particular, the combination of surface morphometry with a systematic experimental framework and use wear analysis has the potential of foreseeing residue distribution areas over the groundstone surfaces, hence providing a key aid in establishing sampling strategies applied to archeological specimens. Here, we propose an approach that applies 3D modeling, performed through a close-range photogrammetry, and the use of GIS software to investigate surface modifications and residue distribution on groundstones used to process wild plants. Our work comprises a dedicated experimental framework in which modern tool replicas have been used to process different species of wild plant foods through grinding, crushing, and pounding. By applying 3D modeling and spatial analysis, we were able to characterize patterns of surface modifications related to each of the worked substances and activities performed. Moreover, we monitored the distribution of starch granules over the experimental groundstone surfaces and its variation in relation to the state of the worked substance and the action carried out. Our results provide one of the first experimental dataset focused on the use of groundstones for wild plant processing, and a reliable methodology for further studies related to the exploitation of stone technology and wild vegetal substances in the past.