Elemental analysis and characterization of ochre sources from Southern Arizona

Abstract

Iron oxides and other associated minerals (ochre) were widely used in ancient times, however, the use and procurement of these materials is not well understood and there has been little research on the elemental characterization of the material compared to other artifact classes. To assess the possibility of identifying ochre differences between locations, the original potential geological sources should be thoroughly characterized. This paper describes the collection of potential geologic sources of ochre in the Tucson basin of Arizona, sampling of those sources, instrumental neutron activation analysis (INAA), and subsequent multivariate analysis of the data. This paper has several goals, including characterizing geochemical trends within and between ochre sources, identifying the important elements in geochemical characterization of ochre, and establishing a database for further investigations. This preliminary study indicates that the inter- and intra-source variations in geological sources of ochre in the Tucson basin region can be differentiated. Future analysis of iron oxide artifacts will be performed to examine correlations between artifacts and sources and provide a basis for further deductions concerning ancient ochre procurement.