Thermoluminescence characteristics of marble and dating of freshly excavated marble objects

This work explores the potentials and difficulties in thermoluminescence (TL) dating of marble objects, which have never been exposed to sunlight since their first burial, by applying a new procedure similar in approach to sediment dating. The idea is based on the observation that exposure to sunlight reduces the TL peaks of marble to a residual level. When the marble is buried after bleaching, radiation from the sample and soil, as well as cosmic radiation, refill the electron traps that have been emptied by the sunlight. Using the additive dose method, an attempt has been made to date a sample of known age (2nd century BC) buried since antiquity. The peak at 290degreesC was selected as the most suitable for dating (activation energy 1.7-2.0 eV, minimum spurious effects, high intensity, linear response up to 50 Gy, bleachable down to the residual level in 1 h). This peak is well defined in most types of marble, common in antiquity (marble from Penteli, Paros, Naxos and Thassos). The age calculation gave 2570 +/- 410 years, which is quite close to the archaeological age. Possible error sources, such as surface impurities and regenerated thermoluminescence, and ways to minimise them are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.