On the zeroing of the thermoluminescence of sediments

A method is described which allows the determination of radiation doses received by mineral grains since their last exposure to sunlight, even if this exposure was of relatively short duration or through a poorly transmitting medium. Tests of the method were made on a variety of zero-age sediments and in most cases gave values ?5 grays, some being <1 gray. This zero-point “error” would lead to an error in the age determination of an old sample of typically 2,000 years, and in one case <300 years. The method should therefore be useful for dating samples older than ～20,000 years and, in some cases, younger ones.