ASSESSING NATURAL CLAY COMPOSITION IN THE VALLEY OF OAXACA AS A BASIS FOR CERAMIC PROVENANCE STUDIES

摘要

The Oaxaca Clay Survey was initiated to provide baseline data on clay composition within the Valley of Oaxaca, Mexico, to assist in provenance determination of prehistoric ceramics. Natural clays were sampled from 135 locations throughout the valley, and analysed using INAA in combination with ceramic petrography. Observed geographical trends in trace-element and mineralogical composition confirm that while parent material (surficial geology) strongly affects clay composition, a continuum of variation exists within the valley. The study develops and tests a continuous spatial model of clay composition that provides greater resolution in ceramic sourcing than bedrock alone. By establishing a regional framework for Oaxaca Valley clays, the survey will support significant advances in our understanding of pottery production and exchange within the valley, and provide a more robust means for monitoring exchange between the valley and neighbouring regions.