Applicability of Electron Spin Resonance (ESR) and Thermoluminescence (TL) Dating Methods Using Quartz Grains for Marine Terrace Sediments

Abstract

We investigate the applicability of sediment dating by ESR and TL, which are based on the assumption of the complete optically bleaching of some radiation defects in quartz grains in the processes of erosion, transportation, and/or sedimentation, and show that the TL method is probably appropriate for dating of the marine terrace sediments. We have carried out optical bleaching experiments using several light sources, and dated a marine terrace sediment whose age had already been estimated from geological information by the ESR and TL methods. The Ti signal is more light-sensitive than E'₁ and Al signals, and is bleached completely by illumination. However, the age obtained using the Ti signal is much older than that estimated by geological data. On the other hand, the TL intensity decreases with illumination, approaching a constant value. This result shows that the TL consists of a light-sensitive component and a residual one, and that we can obtain the intensity of a light-sensitive component easily by an optical bleaching experiment using ultraviolet light. The TL age obtained using the light-sensitive component is in good agreement with geological data.