Application of long time artificial optical bleaching of the E₁’ centre to sediment ESR dating

Three quartz samples extracted from different origins were collected for ESR evaluation to appreciate the optical bleaching characteristics of the E₁’ centre in a long time scale. After exposure of about 400 hours to artificial sunlight, the E₁’ centre were bleached to a steady increasing level, about 2.5 times of its natural level, and the increase level also exhibit a small variability among different sample origins. The constant increasing level provide a significantly evidence for the potential use of the natural signal intensities of quartz E₁’ centre in tracing sediment provenance. The results show that the signal intensity of E₁’ centre increased within beginning 84 h and decreased after 202 h as previous researches have partly predicted. After long time exposed to sunlight, there is no correlation between irradiated samples’ dose rate and its E₁’ centre ESR signal intensity. Thus, no new convenient indication shed light on the possible use of the E₁’ centre for ESR sediment dating.