Radioluminescence dating of sediments: methodological aspects

Radioluminescence (RL) at 865 nm (1.42 eV) — a characteristic of potassium feldspar — has been applied successfully in the dating of Quaternary sediments. The signal can be interpreted as the infrared (IR)-emitting electron transition into a light sensitive trap. Direct measurement of the electron density is thus possible, and this is the basic advantage of this new method. Further investigations have been carried out to develop a precise and reliable IR-RL dating procedure. Besides the already applied additive dose total bleach technique, that of total bleach regeneration and a combination of both (slide technique) were tested in the dating of different aeolian and waterlaid sediments. New bleaching experiments show that about 10 min of light exposure (about 300–700 nm) is sufficient to reach the saturation level of the IR-RL signal. Palaeodose determinations of recently deposited sediments result, in most cases, in an age equivalent to <6 ka. The results of spectral RL measurements suggest that use of non-spectral-resolving detection systems would require an interference filter to reject the unwanted influence of a red RL emission wave-band.