Quartz OSL and polymineral post IR–IRSL dating of the Požarevac loess–palaeosol sequence in north–eastern Serbia

In this study we present a luminescence investigation of samples from the Požarevac loess–palaeosol sequence (LPS) in north–eastern Serbia. The pIRIR290 signal displayed a generally good behaviour and yielded stratigraphically consistent De values. The pIRIR290 ages show very good agreement (within uncertainty) with the expected stratigraphic ages up to about 260 ka. The analyses of the 4–11 μm quartz extracts were performed in order to determine their applicability for luminescence dating. The optically stimulated luminescence (OSL) measurements showed that the fine–grained quartz systematically underestimates the expected equivalent doses for all measured samples. A comparison between natural and laboratory dose response curve showed no overlapping, not even in the lower dose range. Linear modulated –OSL analysis revealed large differences between individual samples where some quartz extracts displayed a different number of components and varying contribution of the fast component. The quartz OSL also shows thermal instability as demonstrated by pulse annealing experiments and thermal fading. For these reasons we do not consider the fine–grained quartz from the Požarevac LPS as a reliable dosimeter.