Abstract

To determine whether Quaternary sediments from small lake and fan deposits can be dated by thermoluminescence (TL) methods, I have applied recently proposed techniques for TL dating to known-age, rapidly deposited silts and have examined the sensitivity of the TL of fine-grain feldspars and quartz to light. These feldspar-dominated silts exhibited little or no detectable anomalous fading. The TL of quartz was observed to be very resistant to light with wavelengths above ~400 nm, whereas that of feldspars was sensitive to all visible wavelengths. No significant resetting of the TL of the 11 ka old glaciolacustrine silt (deposition rate graphic) could be detected with these techniques, implying that silts deposited at such rates into small, glacier-bordered lakes cannot be dated by these methods. However, accurate equivalent doses were measured for the derivative 7.5 ka old mudflow silts (~1 mm/year), but only with the use of the R–Γ technique applied to the feldspars.

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