1. School of Earth Sciences and Key Laboratory of Mineral Resources in Western China (Gansu Province), Lanzhou University, Lanzhou, China
2. State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization, Baotou Research Institute of Rare Earths, Baotou, China
3. Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
4. College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
5. School of Earth Sciences and Resources, China University of Geosciences Beijing, Beijing, China
6. Department of Earth Science, University of Adelaide, Adelaide SA, Australia
7. Geological Survey of Finland, Espoo, Finland