*Masanobu Yamamoto¹, Takafumi Kikuchi¹, Hiromichi Sakura¹, Ryoma Hayashi², Osamu Seki³, Takayuki Omari⁴, Abdullah Sulaiman⁵, Hasrizal Bin Shaari⁶, Lurie Melling⁷ (1.Faculty of Environmental Earth Science, Hokkaido University, 2.Lake Biwa Museum, Japan, 3.Low Temperature Research Institute, Hokkaido University, Japan, 4.The University Museum, The University of Tokyo, Japan, 5.Minerals and Geoscience Department Malaysia, Malaysia, 6.Universiti Malaysia Terengganu, Malaysia, 7.Tropical Peat Research Institute, Malaysia)