1. State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment, Chinese Academy of Sciences Xi'an 710061 China
2. College of Earth and Planetary Sciences University of Chinese Academy of Sciences Beijing 100049 China
3. Faculty of Civil Engineering Hubei Engineering University Xiaogan 432000 China
4. Xi'an Institute for Innovative Earth Environment Research Xi'an 710061 China
5. CAS Centre for Excellence in Quaternary Science and Global Change, Chinese Academy of Sciences Xi'an 710061 China