LIMITATIONS OF INFRARED STIMULATED LUMINESCENCE IN DATING HIGH ARCTICMARINE-SEDIMENTS

The accuracy of infra-red stimulated luminescence (IRSL) dating was ev aluated for modern, late glacial (11 to 13 ka) and older (70 +/- 10 ka and 125 +/- 10 ka) nearshore marine sediments from west Spitsbergen. Despite the increased sensitivity of the IRSL signal to solar reductio n compared with thermoluminescence, the IRSL signal of these sediments was not totally reset, resulting in overestimates of a few 1000 to 10 ,000 years. Subtraction of residuals determined after 10 or 60 minutes of filtered light exposure (wavelengths <540 nm blocked) yielded appa rently concordant age estimates. However, some samples exhibited signi ficant anomalous fading even after preheating and storage; at least on e sample exhibited some increase in the IRSL signal. Although the cons istency of the IRSL age estimates are encouraging, the need for cautio n in luminescence geochronology is emphasized because of outstanding q uestions on signal stability and the extent of solar resetting.