In-Situ pXRF Analysis of Episodic Pictograph Production

Summary

Yokuts ethnography indicates that pictograph sites passed from father to son to grandson within shamanic lineages, suggesting episodic painting at these locations. This practice is archaeologically supported by motif superimpositions and minor stylistic differences at sites. An in-situ pXRF study of red motifs was conducted at site CA-TUL-2871, Springville, CA, in the hopes of analytically distinguishing painting episodes, based on the assumption that chemically dissimilar pigments may have been used that are otherwise visually indistinguishable. Six hypothesized painting episodes were identified based on motif type and panel position. pXRF measurements were taken on 8 motifs and 3 rock surfaces. Multivariate statistical analyses showed no significant differences in the hypothesized groupings and, in 2 cases, between motifs and unpainted rock, suggesting that variations in paint thickness, weathering and rock coatings affected the elemental measurements. An experimental study was then conducted to evaluate the effect of paint thickness, confirming its significance in measured results. Though pXRF remains a useful tool for examining in-situ geochemical variability, numerous variables must be controlled if it is to be applied to distinguish pictograph painting episodes or determining elemental composition.

This Resource is Part of the Following Collections

• Methodology and Interpretation in the Archaeology of Rock Art   •
• Society for American Archaeology 83rd Annual Meeting, Washington, DC (2018)

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Record Identifiers

Abstract Id(s): 20174