Under the direction of Dr. David Meltzer, Ms Rosanna Ridings will collect data for her doctoral dissertation. The goal of her work is to increase the accuracy of obsidian hydration dating and to accomplish this she will analyze carefully excavated and well controlled samples of obsidian tools from the site of Pot Creek Pueblo which is located near the northern Rio Grande, New Mexico. Obsidian (volcanic glass) because it is easy to flake and holds a sharp edge was a widely prized material used to manufacture stone tools. Because freshly flaked surfaces develop a measurable hydration rind and because the depth of the rind is time dependent, many scientists have attempted to use rind thickness to determine age of tool manufacture. However, it is also known that rind development is temperature dependent and that this second independent variable must also be taken into account. Since climate and therefore temperature fluctuate over time, archaeometrists have not determined how temperature measurements should be taken and how subsequent analysis should proceed. Ms Ridings' work will help to resolve this issue. First, she will conduct a systematic comparison of the three methods currently used for measuring and estimating effective hydration temperatures in archaeological sites. She will then compare the results. Secondly, climate of Pot Creek Pueblo will be determined over the last 850 years using both tree ring width and isotopic composition. The Southwest in unique because of the tree ring data which is available. Finally, she will model the depositional history of the artifacts to integrate the change in effective hydration temperature over time. She will then use these data to analyze the obsidian artifacts themselves. Given past work at the site, the age of these materials can be independently determined. This research is important for several reasons. It will help to develop and refine an important archaeological dating technique which is employed in many parts of the world. It will also assist in the training of an extremely promising young scientist.
