Ubiquity of anomalous fading in K-feldspars and the measurement and correction for it in optical dating

Anomalous-fading rates were measured in K-feldspars separated from 49 sedim ent samples, mainly from North America. The intensity of the optically stim ulated luminescence was found to decrease linearly with the logarithm of ti me since irradiation between 2 days and similar to1 year of storage at room temperature. Anomalous-fading rates ranged from 2% to 10% per decade, a de cade being a factor of 10 in time since irradiation. The sample provenances were sufficiently varied that anomalous fading appears to be ubiquitous. W e have experimented with correction of optical ages for anomalous fading on the assumption that the observed fading can be extrapolated a further four decades in time. The corrected ages are in satisfactory agreement with ind ependent ages. These results are restricted to the low-dose region of the d ose response and are not expected to be applicable to samples older than si milar to 20-50 ka.