1. College of Geography Science, Nanjing Normal University, Nanjing 210097, China.
2. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710054, China.
3. Department of Geology and Geophysics, University of Minnesota, MN 55455, USA.
4. State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 210008, China.
5. Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan, China.
6. Department of Geological Sciences, University of Missouri, Columbia, MO, USA.