Debitage

Debitage is all the material produced during the process of lithic reduction and the production of chipped stone tools. This assemblage includes, but is not limited to, different kinds of lithic flakes and lithic blades, shatter and production debris, and production rejects.

Debitage analysis, a sub-field of lithic analysis, considers the entire lithic waste assemblage. The analysis is undertaken by investigating differing patterns of debris morphology, size, and shape, among other things. This allows researchers to make more accurate assumptions regarding the purpose of the lithic reduction. Quarrying activities, core reduction, biface creation, tool manufacture, and retooling are believed to leave significantly different debitage assemblages. Lithic manufacture from a quarried source, or from found cobbles also leave different signatures. Some claim that they can determine the sort of tools used to create the debitage. Others feel it is possible to effectively estimate the work-hours represented, or the skill of the workers based on the nature of the debitage.

Debitage analysis of biface reduction can be used to determine what stage of reduction is represented in waste. Stahle and Dunn (1982) found that, as waste flake size decrease from initial to final stages in biface production, systematic changes in flake size can be used to identify stages of reduction in anonymous debitage samples through comparison with experimental assemblages. Use of Weibull distributions and least square analysis helped Stahle and Dunn confirm that this method can be used backward to estimate reduction stages of particular debitage frequencies. Other studies comparing the debitage of bifacial reduction during different stages has not yielded such positive results. Patterson (1990) was unable to distinguish between the stages of initial edging and secondary thinning using statistical analysis of 14 experimental assemblages.

The typological approach groups together lithics with similar manufacturing histories in order to emphasize patterns of manufacturing behavior (as in Sheets 1975). To use Sheets’ (1983:200) example, macroblades and prismatic blades were separated on the basis of their manufacture, in that the former was removed by percussion, while the latter was removed by a pressure technique. Casual, informal tools from unstandardized cores should be given scrutiny equal to that of formal tools from standardized core reduction.

The presence of cortex needs to be noted for all tool categories in all materials. The presence of cortex indicates the importation of an unworked nodule, with the first flakes both preparing the core by shaping and removing the roughened exterior of the cortex (Sheets 1978:9). The percentage frequency of cortex is an important statistic to help identify lithic production areas. A low incidence of cortex would indicate quarry preforming (cortex removed at the quarry, not at the site).

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