*Asobo nkengmatia elvis ASAAH¹、Tetsuya YOKOYAMA¹、Festus tongwa AKA²、Tomohiro USUI¹、Takeshi KURITANI³、Mengnjo jude WIRMVEM⁴、Hikaru IWAMORI¹、Takeshi OHBA⁴ (1.Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-、2.Institute of Mining and Geological Research, P.O. Box 4110, Yaounde, Cameroon、3.Graduate school of Science, Osaka City University, 3-3-138 Sugimoto, Sumi Yoshi-ku, Osaka 558-8585,、4.Department of Chemistry, School of Science, Tokai University, Hiratsuka, 259-1211, Japan)