Differential Taphonomic Behavior of Flint Types: Experimental Insights and Implications for the Middle Stone Age Assemblages of Wadi Lazalim in the Northern Sahara (Kebili, Tunisia)

Abstract

Several syn and post-depositional processes are responsible for different degrees of site and assemblage formation and disturbance. Understanding the processes that lead to archaeological site formation is essential for interpreting past human activities, settlement patterns, and occupation dynamics. Among these processes, water flow is commonly recognized as a major factor influencing site and assemblage formation and integrity. Lithic taphonomy can add valuable information to the understanding of these natural processes. To better evaluate how different flint types react to both mechanical and chemical stresses, we carried out controlled and sequential experiments on knapped flint artifact replicas. These were realized on two different flint varieties, recognized in the archaeological assemblage of a Middle Stone Age open-air site located at Wadi Lazalim (Southern Tunisia). Our methodological framework is based on a sequential tumbling experiment that simulates the remobilization of artifacts by water. The resulting post-depositional surface modifications (PDSM) were observed and recorded. In addition, a sample of flint replicas underwent chemical alteration in a controlled environment, allowing us to document and measure both patina formation and changes in surface roughness. These experimental results were then compared with a sample of archaeological materials, providing the basis for a preliminary and exploratory hypothesis concerning the taphonomic processes at the site. Here, we observed that most of the alterations appear to be linked to patina formation, whose variable degree and kind are more strongly correlated with differences in raw material texture rather than to the co-occurrence of artefacts from different chronological spans.