1. School of Geography, Geology and the Environment, University of Leicester, Leicester LE1 7RH, UK (e-mail: mri@le.ac.uk)
2. Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
3. Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
4. Department of Environmental Studies, Faculty of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8521, Japan
5. Department of Geology, Vietnam National Museum of Nature, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam