Huei-Ting Lin, National Taiwan University, Taipei, Taiwan, Chuan-Chou Shen, National Taiwan University, High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Taipei, Taiwan, Tsai-Luen Yu, National Taiwan University, Research Center for Future Earth, Taipei, Taiwan and Hong-Wei Chiang, Department of Geosciences, National Taiwan University, Taipei, Taiwan