Affiliation: | aInstitute of Geoscience, University of Tsukuba, Ibaraki 305-8571, Japan bDepartment of Earth System Science, Fukuoka University, Fukuoka 814-0180, Japan cDepartment of Physics and Earth Sciences, College of Science, University of the Ryukyus, Okinawa 903-0129, Japan dNanjing Institute of Geology and Paleontology, Chinese Academy of Science, Nanjing 210008, P.R. China |