SPECTRAL-ANALYSIS OF THERMOLUMINESCENCE IN THE DATING OF POTASSIUM FELDSPARS

A new high sensitivity thermoluminescence system with spectral analysis is used to investigate a current problem in thermoluminescence (TL) dating of sediments. Using the same potassium feldspar material, TL dates have been obtained in several laboratories which vary by up to 40%, depending upon the spectral region selected for the measurements with broad band filters. The new data presented here provide detailed emission spectra which demonstrate that TL emissions from multiple-grain feldspar separates may be so complex that dosimetry problems are inevitable if broad-band filters are used. Filters result in the detection of signals integrated over different emission bands. Measurements of the detailed spectra may be used to indicate which filter combinations will present the least confusing picture for these samples. Spectral analysis appears to be an essential prerequisite for material used in TL dating studies.