Sl. Forman et al., ASSESSING THE ACCURACY OF THERMOLUMINESCENCE FOR DATING BAKED SEDIMENTS BENEATH LATE QUATERNARY LAVA FLOWS, SNAKE RIVER PLAIN, IDAHO, J GEO R-SOL, 99(B8), 1994, pp. 15569-15576
Baked sediments beneath lava flows on the Snake River Plain, Idaho, wi
th independent age control by either C-14 or K/Ar dating were analyzed
to evaluate the accuracy of the thermoluminescence (TL) technique. Th
e age of flows ranges from approximately 2 to 100 ka and multiple TL a
nalyses by the total bleach method yielded ages that overlap at one si
gma with independent chronologic control. The TL signal of one sample
of baked sediment beneath a lava flow with an inferred age of at least
641 +/- 54 ka was near saturation, perhaps reflecting a relatively hi
gh environmental dose rate, and is not datable by TL. This study under
scores several major limitations of luminescence geochronology, the na
tural spatial and temporal variability in environmental radioactivity
and the susceptibility of silicate minerals to the growth and retentio
n of a luminescence signal. Despite these limitations, the results dem
onstrate the utility of luminescence geochronology to date volcanic er
uptive events during the Quaternary.