1. College of Earth Environmental Sciences & Key Laboratory of Western China’s Environmental Systems, Ministry of Education, Lanzhou University, Lanzhou 730000, China
2. Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78712, USA
3. School of Earth Sciences & Key Laboratory of Western China’s Mineral Resources of Gansu Province, Lanzhou University, Lanzhou 730000, China