[1]Key Laboratory of Western China's Environmental Systems, Ministry of Education, College of Earth Environmental Sciences, Lanzhou University, Lanzhou 730000, China;
[2]Gansu Provincial Institute of Cultural Relics and Archaeological Research, Lanzhou 730000, China;
[3]Qinghai Provincial Institute of Cultural Relics and Archaeological Research, Xining 810007, China;
[4]Cultural Relic Conservation Institute, Lhasa 850000, China;