Japan Geoscience Union Meeting 2022

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[J] Oral

H (Human Geosciences ) » H-QR Quaternary research

[H-QR05] Innovative applications of luminescence and ESR dating to geosciences

Wed. May 25, 2022 3:30 PM - 5:00 PM 201B (International Conference Hall, Makuhari Messe)

convener:Shin Toyoda(Department of Applied Physics, Faculty of Science, Okayama University of Science), convener:Toru Tamura(Institute of Geology and Geoinformation Geological Survey of Japan, AIST), Yorinao Shitaoka(Department of Environment System, Faculty of Geo-environmental Science, Rissho University), Chairperson:Yorinao Shitaoka(Department of Environment System, Faculty of Geo-environmental Science, Rissho University), Shin Toyoda(Institute of Paleontology and Geochronology, Okayama University of Science), Toru Tamura(Institute of Geology and Geoinformation Geological Survey of Japan, AIST)

3:45 PM - 4:00 PM

[HQR05-02] Thermal stability and bleaching characteristic of sediments by electron spin resonance

*Naoya Obata1, Shin Toyoda2 (1.Okayama University of Science, 2.Institute of Paleontology and Geochronology, Okayama University of Science)

Keywords:ESR, quartz, thermal stability, sediment, bleach

Electron spin resonance (ESR) dating with quartz is one of the methods applied to sediments together with optically stimulated luminescence (OSL) dating, where it is assumed that exposure to sunlight erases the dating signals. ESR method has an advantage that it can be applied to samples with older ages than OSL method, but on the other hand, the dating signals bleach harder than OSL signals. The latter bleach in several ten seconds to several hours at longest while ESR signals take several thousand hours, being possible that the residual signal intensity is significant. It is known that the Al center (a hole trapped at an Al ion replacing silicon in quartz) has two components, bleachable and unbleachable, where the former has to be subtracted to estimate the ages while the thermal stabilities corresponding to those components have not been well discussed. In the present paper, the characteristics of ESR dating signals (Al and Ti centers) on bleaching and on heating are systematically investigated.