Impact of gamma densitometry on the luminescence signal of quartz grains

摘要

Most of the marine sediment cores collected in the past 10 years by the ODP and IMAGES programs have been processed using a multi-sensor core logger (MSCL, Geotek). This system estimates the density of sediment using the gamma-ray attenuation of a Cs-137 source. To date, optically stimulated luminescence (OSL) dating has not been applied to sediments from cores treated in this way, because of the possible impact of this exposure on the existing luminescence signal. We have investigated the effect of such gamma-ray irradiation by test exposure, measurement and estimation, and conclude that the usual Cs-137 exposure from gamma-ray attenuation densitometry has no impact on the luminescence signal of quartz grains in sediment cores. For longer exposure to the Cs-137 source, a formula is provided to calculate the received dose. This result will permit the OSL dating technique to be applied to the voluminous body of marine cores already collected and processed by MSCL.