TRACING THE INTERACTION OF CLAYS AND TRANSFORMATIVE HUMAN TECHNOLOGIES: THE BULK CHARACTERIZATION OF POTTERY MICROSTRUCTURES VIA SYNCHROTRON X-RAY SCATTERING

The ancient and historical pottery recovered from archaeological sites can be highly varied in both the sources of raw clay material and the multifarious techniques of paste preparation, formation, and firing used to produce different types of containers. In order to robustly sample such diverse pottery “assemblages,” archaeologists have long relied on various geochemical approaches (INAA, XRF, ICP-MS, etc.) to asses the distributions of trace elements present in pottery and source clays. While geochemical approaches are powerfully resolving and now well established, their resultant data focus finely on clay procurement and subsequent pottery exchange, shedding little light on production practices such as paste preparation, formation, and firing (essential axes of technostylistic variability). This study presents synchrotron-based small- and wide-angle X-Ray Scattering (SAXS/WAXS) as a new and agile method for the analysis of such production parameters through its examination of ceramic microstructures, transformed by the interaction of specific raw materials and particular human techniques. Our method draws on the ability of SAXS/WAXS to fully penetrate ceramic bodies with high-energy "transmission geometry" and its capacity to quickly and nondestructively analyze large (n>10,000), well-stratified pottery samples. This approach is contrasted with traditional analyses of microstructure, which need to marshal multiple methods of destructive, time-intensive analysis of relatively small numbers of samples (thin section petrography, X-ray diffraction, re-firing experiments, etc.). Experimental and archaeological case studies from the pottery collection of the Making of Ancient Eurasia (MAE) Project, a collaborative research effort by Eurasian archaeologists at the University of Chicago and materials scientists at Argonne National Laboratory (ANL), are used to demonstrate the protocol development process and the analytical utility of the method.