Chemical and Radiocarbon Analyses of Paint Samples from Oxtotitlán

Summary

The prehistoric rock paintings in the Oxtotitlán site are thought to be among the earliest of Mexico and represent the beginning of the highly influential Mexican muralism tradition. The proposed antiquity of the murals is based primarily on stylistic interpretation of the motifs represented in the paintings. Our objective was to use radiocarbon analyses of organic matter in the paint and biofilms covering paint layers to provide more direct evidence as to the ages of the artifacts. Small paint chips were collected from three murals, including a black and red shield image, a deteriorated area without a decipherable motif, and from the polychromatic Raptor Lord Mural (C-1 Mural). Non-painted surfaces adjacent to the paintings were collected to provide background information. Two strategies were used to determine or constrain the ages of the artifacts. First was the extraction of organic carbon directly from the paint using a low-temperature oxygen plasma, converting it to carbon dioxide that was cryogenically isolated for the AMS radiocarbon analysis. Second, in cases where the paint did not contain datable organic carbon or the background deemed too high, we radiocarbon dated the calcium oxalate biofilm covering the paint to provide a minimum age of the artifact.

This Resource is Part of the Following Collections

• Society for American Archaeology 81st Annual Meeting, Orlando, FL (2016)   •
• Cave Art and Archaeology at Oxtotitlán, Guerrero

Keywords

Spatial Coverage