1. School of Earth Sciences, Key Laboratory of Western China's Mineral Resources of Gansu Province, Lanzhou University, Lanzhou 730000, China
2. Institute for Rock Magnetism, University of Minnesota, Twin Cities, Minneapolis, MN 55414, USA
3. College of Urban and Environmental Science, Xinyang Normal University, Xinyang 464000, China
4. Research Centre of Global Change, School of Geographical Science, Fujian Normal University, Fuzhou 350007, China
5. Department of Environment and Geography, Macquarie University, NSW 2109, Australia