LUMINESCENCE AND ELECTRON PARAMAGNETIC RESONANCE PROPERTIES OF PREHISTORIC CERAMICS FROM AL-KHIDAY EXCAVATION SITE, SUDAN

Abstract

Direct dating of prehistoric pottery from desert environment is complex, due to the lack of the attributes required for the archaeological chronological methods. Pottery samples from Sudan were therefore studied by means of Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) to establish the best measurement protocol for dating such ceramics. These techniques exploit the time-dependent accumulation of charge carriers in defects present in mineral components of ceramics, like quartz and feldspars. To evaluate the amount of such charges, which is a measure of the energy released in matter by natural ionizing radiation, two different protocols were firstly tested: the Multiple Aliquot Additive Dose protocol (MAAD) for TL and the Single Aliquot Regenerative dose protocol (SAR) for TL and OSL. Both methods allowed the discrimination of Neolithic from Mesolithic pottery, even if the data were generally affected by high uncertainties, and the presence of a few aberrant results was observed.

Moreover, a further independent technique for measuring the population of defects was attempted: the Electron Paramagnetic Resonance (EPR), in both Continuous Wave (CW-EPR) and Pulsed methods (EDEPR). This application was problematic in naturally irradiated samples, due to the low EPR sensitivity and the high Fe (III) background spectrum observed under Continuous Wave measurements. Preliminary encouraging results were instead obtained with the Pulsed technique, which was only tested before on few artificial irradiated samples.