The implication of sodium-rich plagioclase minerals contaminating K-rich feldspars aliquots in luminescence dating

Luminescence dating was performed on three different sediments, collected in Italy. Measurements were accomplished on K-rich minerals extract, where we dispensed a small amount of grains on each aliquots. Anomalous fading was measured for each aliquot. We observed a negative correlation between the measured age and associated rate of fading, for each sample. In two samples, a few outliers were identified, where they displayed a lower measured age and fading rate. We positively identified the presence of Na-rich plagioclase minerals dominating the luminescence output of these outliers.

► Luminescence dating of K-feldspar in southern Italy. ► Precise anomalous fading measured in helium. ► Negative correlation found between measured age and fading. ► Internal abundance of K, Na and Ca measured in individual grains by EPMA.