APPLYING LUMINESCENCE DATING ON FLUVIOGLACIAL OUTWASH DEPOSITED AFTER THE LGM NEAR CHICAGO (USA)
Most samples were retrieved from light-shielded vertical cores (mud rotary and probing), along with some good old hammered pipe into riverbank exposures. This presentation will highlight the advantages and disadvantages of each sampling approach.
For luminescence dating it is most likely that only a portion of the sediment would have had its latent luminescence signal fully reset before burial, as these sedimentary units were deposited by (turbid?) meltwater likely proximal to the ice margin. To tackle this issue we opted to measure the OSL from quartz, using a very small aliquot size (1 mm).
Multiple samples were measured from stratigraphically equivalent sedimentary units. We obtained statistically identical OSL age from paired samples. In addition, the IRSL (infrared stimulated luminescence) age from K-feldspar, measured from some sample, were also statistically identical to their duplicate OSL age from quartz. Finally, these luminescence ages are concordant with radiocarbon ages, derived from correlated sedimentary units. All these observations bolster our confidence in measuring an accurate luminescence age from these deposits, despite the challenges they offered at the onset.