Correlation of archaeological ceramics and clays using an external-beam PIXE analysis of the major elemental constituents
Time-consuming trace-element analysis is often used to determine the origin of archaeological artifacts. In an effort to locate the source of clay used to manufacture archaeological ceramics from eastern Oklahoma, we find that a determination of major elemental constituents using external-beam PIXE analysis is a useful technique for determining the probability of common origin. Using a 7 nA, 1.5 MeV external proton beam, it takes less than one minute to determine the concentration of the major elements to an accuracy of better than 5%. This rapid analysis makes it possible to quickly select pottery sherds of similar composition and eliminate clay samples which are not strongly correlated with the sherds. Trace-element analysis of these strongly correlated samples can then in principle be used to make an absolute identification. Major elemental analysis is thus useful for survey work where many samples must be examined. The effects of sample inhomogeneity and the firing process, as well as the probability of false correlations, are discussed.