Revised Drying Conditions in Rehydroxylation (RHX) Technique for Dating Ceramic Artifacts

Summary

The Fired Clay Ceramic Rehydroxylation Dating (RHX) technique shows potential for establishing date of manufacture for archaeological ceramics, however for certain samples, such as those recovered at Umbro Greek and Sant’ Ancieto sites, the calculated ages were outside of the expected range by many thousand years. The observation of this over-shooting issue suggested that either the non-refractory mass (Mnrc) or some strongly bonded physical water were left during the ordinary drying process at 105°C. XRD analysis of the samples eliminated the possibility that other minerals retained extra crystallized water. FTIR analysis of the samples between 100-700°C indicated that only water and CO2 were lost from the samples, allowing researchers to rule out mass loss from carbonizing organic compounds. Combined FTIR and TG analysis indicated that overshooting age calculations derived from the release of physical water. By retesting the samples using a dehydroxylation firing at 300°C, all those less stable components were dried leaving only hydroxyl water contributing to the RHX mass. With the newly measured dehydroxylated mass, the RHX dating formula produced better dates. Calculated dates for two samples, 2,732 and 2,646 years) are now very close to their expected age ranges (2400-2300 and 3210-2850 years respectively).

SAA 2015 abstracts made available in tDAR courtesy of the Society for American Archaeology and Center for Digital Antiquity Collaborative Program to improve digital data in archaeology. If you are the author of this presentation you may upload your paper, poster, presentation, or associated data (up to 3 files/30MB) for free. Please visit http://www.tdar.org/SAA2015 for instructions and more information.

This Resource is Part of the Following Collections

• Society for American Archaeology 80th Annual Meeting, San Francisco, CA (2015)   •
• Developments in Fired Clay Ceramic Rehydoxylation Dating (RHX Dating)

Keywords