Key Laboratory of West China's Environmental System (MOE);
Lanzhou University;
Lanzhou 730000;
China;
Department of Anthropology;
University of California;
Davis;
CA 95616;
USA;
Department of Sociology;
Social Work;
and Anthropology;
Utah State University;
Logan;
UT 84322;
USA;
Gansu Province Institute of Cultural Relics and Archaeology;
Lanzhou 730000;
China;
Preservation Institute ofDadiwan;
Qin'an 741600;
China;
Center for Accelerator Mass Spectrometry;
Lawrence Liverrnore National Laboratory;
Livermore;
CA 94550;
USA;
Key Laboratory of Desert and Desertification;
Cold and Arid Regions Environmental and Engineering Research Institute;
Chinese Academy of Sciences;
Lanzhou 730000;
China;
