[S-TT53] 地球科学へのルミネッセンス年代測定の貢献

[STT53-02] 海底堆積物の光ルミネッセンス年代測定- レビュー-

*杉崎 彩子¹、Buylaert Jan-Pieter^2,3、Murray Andrew² (1.産業技術総合研究所、2.Aarhus University、3.Technical University of Denmark)

キーワード：光ルミネッセンス年代測定、第四紀

Optically stimulated luminescence (OSL) dating determines the time that has elapsed since sediments were last exposed to sunlight; the technique is widely applicable to late Quaternary sediments. An OSL age is calculated by dividing the radiation dose that has been absorbed by mineral grains during burial by the rate of energy absorption from ionizing radiation during burial (dose rate). The dose is measured using luminescence techniques and the dose rate is calculated from a knowledge of the concentration of natural radionuclides (U- and Th-series and ⁴⁰K) in the sediment matrix. A prerequisite for obtaining an accurate luminescence age is that all grains have been exposed to sufficient sunlight to empty the prior trapped charge prior to burial.
In contrast to studies on land, the application of OSL dating to marine sediments has been limited. The main reasons appear to be difficulties during sample collection (ensuring light shielded condition), the usually fine-grained nature of the material and the evaluation of the life-time burial water content. Here we give an overview of luminescence dating applied to marine cores, discuss the recent methodological advances and the upper and lower age limits. Finally, we show the potential of OSL dating of marine cores when high sampling depth resolution is available.