Chapter 2 - Luminescence analysis (OSL and TL) from Karabai I

Abstract

This chapter reports a pilot study by two luminescence laboratories on samples from the 2004 excavations of Karabai I. The Scottish Universities Environmental Research Centre (SUERC) examined the optical stimulated luminescent (OSL) properties of the sediments using a method called luminescence profiling (Burbidge et al. 2007); the Max-Planck-Institute for Evolutionary Anthropology, Leipzig attempted to analyse the thermoluminescence (TL) age of a small collection of heated stones. Luminescence profiling is a rapid survey method for assessing the suitability of sediments for full dating based on the presence of particular minerals, grain-sizes and luminescence signals. At Karabai I the study revealed many factors that would complicate a subsequent full dating study, however a tentative age range of 60-115 ka was obtained using the ‘IRSL’ and ‘post IR & OSL TL’ signal from the polymineral coarse fraction. Luminescence signals based on quartz were found to be saturating and so could provide only minimum ages. Only one heated rock of sufficient mass, recovered in square 4H archaeological layer 2, exhibited acceptable properties for successful dating. The resulting TL age, 142 ± 23 ka (EVA-LUM-06/01), places Karabai I within MIS 6. This contrasts with the luminescence profile study that suggested sedimentary deposition within MIS 4-5. In both studies it is important to recognise the tentative nature of these conclusions.