Auto-Regenerative TL Dating of Zircon Inclusions

Microscopic zircon crystals exist in small amounts in most pottery. Zircons are of particular interest because they are one of the few TL sensitive minerals whose palaeodose is almost entirely internal. Since the external dose normally contributes only 3% to the natural TL, errors introduced by uncertainties in the environmental dose rate are virtually eliminated. Because of their high internal dose rate one can date the last firing of the zircons by storing the grains for six months after measurement of the natural TL. During the storage a small TL signal will be auto-regenerated. The age is then given by Age = (Natural TL x storage time)/(Auto-regenerated TL). This technique overcomes the difficulties, encountered in the standard TL dating procedure, from zoned TL emission. However, this auto-regenerated TL signal is small, requiring the development of high sensitivity TL apparatus. A variety of samples have been successfully dated by this method, with dating accuracies of 4 to 45%. The results are reported here.