Identification of well-bleached grains in the optical dating of quartz

A simple means of identifying poorly bleached samples is proposed for the d ating of quartz using the single-aliquot additive-dose optically stimulated luminescence (OSL) protocol. For a well-bleached sampler it is shown that the equivalent dose (D-c) does not change with the ratio of the natural OSL from a brief (0.1 s) stimulation to the 110 degreesC thermoluminescence fr om a subsequent small test dose. In contrast. in a poorly bleached sample. the D-c increases strongly at higher values of the ratio. These observation s suggest that this ratio can be used as an indicator of whether or not a s ample is well bleached. The OSL/TL ratio is also likely to be sensitive to such factors as thermal history and feldspar contamination. (C) 2001 Elsevi er Science Ltd. All rights reserved.