Thermoluminescent Dating of Ancient Ceramics

Abstract

MOST clays contain a few parts per million of uranium and thorium and a few per cent of potassium, so that the body of an ancient pot receives a radiation dose of the order of 1 r./g/yr., mainly from α-particles. Some of this energy is stored in the constituent minerals of the clay either by the creation of new lattice defects or by the filling of existing impurity traps. On heating, some of this energy is emitted as visible light. In the majority of cases the pot will have been fired to about 800° C in antiquity when it was made, so that accumulation of stored energy begins anew from that time, and there is the possibility, first suggested by Daniels et al.¹, that the thermoluminescent glow observed from ancient pottery could be used as a measure of its age. Thermoluminescent study, in the dating of lava flows³ and limestones², for example, is fairly well known as a geological tool, but little has been heard of its archæological exploitation since an announcement by Kennedy and Knopff⁴ in 1960 and a description of technique by Houtermans, Grögler and Stauffer⁵ in 1960. The present communication reports the results obtained on potsherds ranging back to 8,000 years in age and widely spread in provenance.