IDENTIFICATION OF WELL-BLEACHED GRAINS IN THE OPTICAL DATING OF QUARTZ

Abstract

A simple means of identifying poorly bleached samples is proposed for the dating of quartz using the single-aliquot additive-dose optically stimulated luminescence (OSL) protocol. For a well-bleached sample, it is shown that the equivalent dose (De) does not change with the ratio of the natural OSL from a brief (0.1s) stimulation to the 110°C thermoluminescence from a subsequent small test dose. In contrast, in a poorly bleached sample, the De increases strongly at higher values of the ratio. These observations suggest that this ratio can be used as an indicator of whether or not a sample is well bleached. The OSL/TL ratio is also likely to be sensitive to such factors as thermal history and feldspar contamination.