Japan Geoscience Union Meeting 2014

Presentation information

Oral

Symbol H (Human Geosciences) » H-TT Technology & Techniques

[H-TT35_1PM1] Developments and applications of AMS techniques for earth and human environmental research

Thu. May 1, 2014 2:15 PM - 4:00 PM 311 (3F)

Convener:*Toshio Nakamura(Center for Chronological Research, Nagoya University), Hiroyuki Matsuzaki(School of Engineering, The University of Tokyo), Kimikazu Sasa(Research Facility Center for Science and Technology, University of Tsukuba), Hisao Nagai(Faculty of humanities and Sciences, Nihon University), Masayo Minami(Center for Chronological Resarch, Nagoya University), Chair:Masayo Minami(Center for Chronological Research, Nagoya University)

2:15 PM - 2:30 PM

[HTT35-P01_PG] Geoscience studies using by AMS at JAEA-AMS-TONO in the Tono Geoscience Center of the Japan Atomic Energy Agency

3-min talk in an oral session

*Yoko KOKUBU1, Akihiro MATSUBARA1, Tatsumi HANAKI1, Ken-ichi YASUE2, Koji UMEDA2 (1.Tono Geoscience Center, Japan Atomic Energy Agency, 2.Geological Isolation Research and Department Directorate)

Keywords:AMS, Dating, C-14, Be-10, Al-26

The JAEA-AMS-TONO facility was established in 1997 at the Tono Geoscience Center, Japan Atomic Energy Agency (JAEA). Our AMS system is a versatile system based on a 5MV tandem Pelletron type accelerator (National Electrostatic Corporation, US) and has been made available for 14C-, 10Be- and 26Al-AMSs. These multi-nuclide AMSs have been mainly applied to neotectonics and hydrogeology, in support of our research on geosphere stability applicable to the long-term isolation of high-level radioactive waste. Furthermore, the 14C- and 10Be-AMSs are used for geoscience, environmental science and archaeology by researchers of universities and other institutes under the JAEA's common-use facility program.Major contribution of radiocarbon (14C) dating through our 14C-AMS to geoscience studies are as follows. Yasue et al. identified fault displacement and stratigraphic correlation of black soils based on 14C ages (presented in this conference). They conducted 14C dating of the black soil collected from a trench wall of the Atera Fault, Gifu. The results of 14C date show that the soil age varies from 4,000 to 2,000 y with depth of the sampling points and the soil was deposited at approximately constant rate. Imaizumi et al. (2006) estimated the faulting age based on 14C dating of soils at the Senya Fault in the Toen Fault Zone, Yokote Basin, Akita. It was found that the ages range between 1000 - 1300 y, indicating that the Senya Fault was caused by the Rikuu Earthquake in the year of 1896. Sasaki et al. (2006) studied local climate change in an inland basin. Pollen records and 14C ages of sediments in Ohkute Basin, Gifu were used to reconstruct past climate change. The results suggested that the local climate has been warmer for the last 10000 yBP.Since the fiscal year of 2013, the 10Be-AMS has been routinely measured and used to study long-term erosion rates of weathered granitic soil surfaces using cosmogenic 10Be depth profile under the joint research program with the National Institute of Advanced Industrial Science and Technology (AIST). Recently, we have started development of 26Al-AMS. The system tuning and test measurement have been carried out for routine measurement. The development has so far done well and the routine measurements of the 26Al-AMS will be started in near future. The 10Be- and 26Al-AMSs will be used to estimate the exposure age of basement rocks as well as the sedimentation rate and the assessment of volcaniclastic material ejected during volcanic eruptions.