Intra-raw material variability and use-wear formation: an experimental examination of a Fossiliferous chert (SJF) and a Silicified Wood (YSW) from NW New Mexico using the Clemex Vision processing frame

This study is part of an ongoing research initiative designed to further standardize the collection and evaluation of use-wear data through the use of a combination of digital image, GIS, and nanoindentation analyses. The focus of the present paper is on using digital imaging analysis to evaluate the role of intra-raw material variability in use-wear formation by experimentally making and using five flake scrapers made from San Juan Fossiliferous chert (SJF) and five made from Yellow Silicified Wood (YSW). Both raw materials were commonly used in prehistoric northwestern New Mexico. The results of Clemex digital image analysis show that there is variation in use-wear accrual rates between the five SJF flake scrapers and between the five YSW flake scrapers. They also show that the degree of this variation differs between SJF and YSW. It is argued that understanding this variability is a key element in clarifying the nature of use-wear formation and therefore in improving the reliability of its archaeological interpretation.