ESR dating of quartz and plagioclase from volcanic ashes using E'1, Al and Ti centers

Two volcanic ash layers named Kasuri and Sakura in the Osaka Group were dated by electron spin resonance (ESR). The equivalent dose obtained using the ESR signal intensity of Ti centers was larger than that using Al centers for plagioclase in the Kasuri ash layer. An annealing experiment indicates that artificial γ ray irradiation produces unstable Al centers as well as stable ones in plagioclase, while the stability of Ti centers in both irradiated and in non-irradiated aliquots are the same. The age of obtained using Ti centers in plagioclase is consistent with the stratigraphy and fission track ages. The total accumulated doses obtained using E', Al and Ti centers were consistent for quartz in the Sakura ash layer. The thermal stability of E' centers is also investigated by an annealing experiment (author)