10:00 AM - 10:15 AM
*Yoshihiro Nakamura1, Yutaka Takahasi1, Tohru Danhara2, Hideki Iwano2, Takehumi Hirata3 (1.Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, 2.Kyoto Fission-Track Co., Ltd., 3.Geochemical Research Center, The University of Tokyo)