OSL dating of fine and coarse quartz from a Palaeolithic sequence on the Bistrița Valley (Northeastern Romania)

Discrepant ages are obtained between fine (4-11 μm) and coarse (63-90 and 90-200 μm, respectively) quartz for equivalent doses higher than ∼80-100 Gy. However, a very good agreement is achieved for the youngest sample, with an age of ∼8 ka (with a De of 38 Gy for fine and 35 Gy for coarse grains, respectively). The comparison with independent control provided by radiocarbon dating suggests better agreement of ages calculated for coarse quartz. Our results are once again proof that concerns should be raised regarding the reliability of the equivalent doses obtained on quartz samples for which the laboratory dose response cannot be fitted by a single saturating exponential function. Further systematic investigations are required regarding the very different saturation characteristics of fine and coarse grained quartz.