FOCUS: Provenance of ceramics revealed by magnetic susceptibility and thermoluminescence

A new method for provenance determination of ceramics is presented. The samples were measured for magnetic susceptibility and for the TL intensity produced by artificially induced radiation in a pre-heated sample. Characteristic differences in magnetic susceptibility and TL sensitivity were found to exist between different clay sources, and in a diagram of susceptibility versus TL intensity, ceramics of different provenances often plot in distinctly different areas. Samples of 0-01-1 g of burnt clay were used. The method has been tested on a dozen archaeological sites, three of which are presented here as examples. Choice of tempering material, firing temperature, and oxygen tension during firing affect the susceptibility and the TL signals somewhat, and these effects have been tested experimentally.