Distinguishing quartz and feldspar in single grain luminescence measurements

Luminescence dating of single grains requires a method of distinguishing between quartz and feldspar based solely on their luminescence behaviour. Several methods are tested, including the shape of optically stimulated luminescence (OSL) decay curve, the effect of infrared stimulation upon the OSL signal, and the change in OSL decay curve shape and OSL intensity as a function of the temperature of the sample during stimulation. Of these, the last requires a large number of additional measurements, whilst the first is a poor discriminant. The most efficient means of distinguishing quartz and feldspar grains is by taking the ratio of the OSL signal when measured with and without prior infrared stimulation. This is termed the OSL IR depletion ratio.