Feldspar IRSL emission spectra at high and low temperatures

The physical basis of feldspar dating using the Infrared Stimulated Luminescence (IRSL) method is still unknown to a large extent. This study shows the IRSL behaviour of a sediment-extracted microcline in a temperature range from - 130 to +200 degrees C. The low temperature region was used to calculate the activation energy to 0.15 eV. The behaviour above room temperature, as well as additional experiments on museum specimens, gives cause for the introduction of a long lived state (some tens of milliseconds) to the IRSL model, which is situated in the recombination path of the 560 nm emission. Some consequences on dating are discussed. 1997 Elsevier Science Ltd.