Thus, the depositional age of the samples should young seaward (from YG-1 to YG-8).Sample preparation and luminescence measurement were done at the luminescence laboratory of the Geological Survey of Japan.Sadakata (1991) divided the ridge sequence into three roughly parallel ranges from the lagoonal coast to the ocean; these were named the Uchihama, Nakahama, and Sotohama ranges.The Uchihama Range is the innermost of the three ranges and extends from the southeastern end of the barrier to about 2 km from the Sakai Strait.
Absolute dating of the ridge sediments will help to quantify the effect of human activity on the geomorphology of this region.
The corrected age is highly dependent on the g-value, which if slightly inaccurate would have caused the overestimate.
The uncorrected post-IR IRSL ages were underestimated, and we consider that the post-IR IRSL signal faded.
However, given the negative g-values, application of an appropriate fading correction was not feasible.
The corrected IRSL ages of the younger samples, coupled with an assumption of residual dose, roughly agreed with the historical shoreline changes, indicating that the rate of shoreline progradation increased markedly during the recent period of mining-related enhanced sediment discharge. All samples showed higher equivalent doses for the post-IR IRSL signal.