Experimental characterization of pit formation process using laser confocal scanning electron microscope in the Mesolithic site of Font del Ros (Spain)

Abstract

The study of macrolithic tools in the Mesolithic site of Font del Ros (Southeastern Pyrenees, Spain) has been allowed to identify a group of pitted stones. The tencnofuncional attribution of these elements, discussed in Roda Gilabert et al. (2012) states that the origin of these use-wear is related to the bipolar knapping. In this presentation we propose to document the plastic deformations linked to bipolar technique and record the modification of the active surfaces on both anvil and hammer stones. Sequential monitoring of bipolar size by laser scanning confocal microscope (LSCM) allows quantitative data and characterizes the formation of pits. The analysis of variables as slope and roughness express the topographical variability and synthesize the characterization of active surfaces. The micro scans show plastic deformation and allow the quantification of the use-wear patterns. Similarly, the comparison of these data with artifacts from archaeological traces reveals significant differences between the different types of use-wear. Surface metrology indicates that pitted stones are related to thrusting percussion on hard materials. These tools are key in identification identify bipolar knapping. The Scanning Laser Confocal Microscope (SLCM) is a reliable technique for the quantitative analysis of usewear on macrolithic tools.