*Tetsuya Sakuyama¹, Yuma Hayashi¹, Kenji Shimizu², Takayuki Ushikubo², Takeshi Hanyu³, Jun-Ichi Kimura³, Wei Tian⁴ (1.Faculty of Science, Osaka City University, 2.Kochi Institute for Core Sample Research, JAMSTEC, 3.JAMSTEC, Yokosuka, 4.Peking University)