APPLICATIONS OF OPTICALLY STIMULATED LUMINESCENCE (OSL) DATING IN THE STUDY OF CHANGE IN CLAY SOURCE OF OLIVINE-TEMPERED CERAMICS IN THE ARIZONA STRIP AND ADJACENT AREAS IN THE AMERICAN SOUTHWEST

The ceramic assemblage in the Arizona Strip and adjacent areas in Utah and Nevada is characterized by widely-distributed ceramics tempered with olivine, a volcanic mineral, between A.D. 100 and 1300. The source of this olivine is thought to be at Mt. Trumbull and Tuweep, near the northwest rim of the Grand Canyon. Olivine-tempered ceramics are distributed westward from these olivine source areas over a range of more than 100 km. The ultimate goal for this study is to understand the evolution of production and distribution patterns of olivine-tempered ceramics among agricultural groups in the unstable environment of northern Arizona and southern Nevada.

To investigate the source of olivine-tempered ceramics, chemical compositional analysis on ceramic samples and clay, using Laser-ablation ICP-MS (LA-ICP-MS), was used. The results of the analysis on 311 ceramic samples and 90 clay samples identified six compositional groups in the clay matrix data of olivine-tempered ceramics found in the Mt. Trumbull and lowland Virgin areas 100 km west of the Mt. Trumbull source area. Further, this analysis also shows that at least two groups are matched to local clays in Mt Trumbull and one is matched local clays in the lowland Virgin area. This study hypothesizes that some of the olivine-tempered ceramics were made in Mt. Trumbull and transported to the lowland Virgin area and some were made in the lowland Virgin area using the olivine temper transported from Mt. Trumbull.

In this paper, I will particularly examine how this production and distribution pattern of olivine-tempered ceramics changed over time. Optically stimulated luminescence (OSL) dating is used to determine the age of ceramics from each compositional group to examine how the patterns changed. I expect that a more accurate reconstruction of change in the archaeological record, combining the chemical compositional data with a direct dating technique will enable a more accurate evolutionary account of culture change.