Microanalytical Insights into Pigment Selection and Preparation in British Columbia Rock Art

Summary

Pictographs are important archaeological locales that can provide insight into histories of mineral use and pigment preparation. We present the results of a series of microanalytical explorations of a pictograph panel at Boling Point, Babine Lake, British Columbia. Examination by high-resolution microanalysis (SEM-EDS, TEM, FTIR, micro-Raman) has revealed evidence pertaining to source selection of the iron-oxides used to produce the pictographs, the weathering and condition of the panels, and potential evidence for pigment enhancement by pyrotechnology. The pictographs at Boling Point were painted on an outcrop of argillaceous limestone covered in a kaolinitic weathering deposit. This natural canvas, and subsequent accretionary deposition, has aided in the long-term preservation of the panel. The pigment is composed of a homogenized mixture of ferrihydrite and hematite that was biogenically produced ex situ, most likely in a spring deposit, by aquatic iron-oxide producing bacteria, including Leptothrix ochracea and Gallionella spp. Preliminary results of high-sensitivity magnetometry also suggest that the pigment was thermally altered to induce iron oxide phase change to enhance colour properties. Our results demonstrate the potential of microanalytical applications in rock art studies, and have implications for pigment source selection, preparation practices, and decision-making in the placement of pictographs in British Columbia.

This Resource is Part of the Following Collections

• Society for American Archaeology 83rd Annual Meeting, Washington, DC (2018)

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Record Identifiers

Abstract Id(s): 21493