Thermal assistance in TA – OSL signals of feldspar and polymineral samples; comparison with the case of pure quartz

•TA – OSL for pure K-feldspar sample as well as a K-feldspar rich sample is studied.•The shape of the TA – OSL signal indicates an initial part followed by a flat part.•The features of polymineral sample resemble the TA – OSL features of pure quartz.

Thermally assisted optically stimulated luminescence (TA – OSL) is studied for the cases of polymineral, rich in K-feldspar sample as well as one pure sample of K-feldspar. For both cases, the shape of the TA – OSL signal indicates an initial, fast decaying part which is followed by a flat, very slowly decaying part with intensity much larger than the ordinary background noise signal. Thermal assistance characteristics indicate that for the case of pure K-feldspar, the signal originates from a unique very deep trap. The experimental features of the TA – OSL signal in the case of polymineral sample resemble much the corresponding TA – OSL features of pure quartz, in terms of both glow curve shape, especially at high stimulation temperatures, as well as signal intensity and its dependence on the stimulation temperature. Nevertheless, TA – OSL stimulation at low, ambient temperatures provide strong hints towards the contribution of K – feldspars to this signal. Proper selection of the stimulation temperature could possibly discriminate the TA – OSL signal originating from quartz and feldspars.