Xin Li^1,2, Yishi Yang³, Minxia Lu¹, Yiwen Lu¹, Wenyu Wei¹ and Minmin Ma¹, (1)Lanzhou University, MOE Key Laboratory of Western China's Environmental System, College of Earth & Environmental Sciences, Lanzhou, China, (2)Lanzhou University, College of Public Health, Lanzhou, China, (3)Gansu Provincial Institute of Cultural Relics and Archaeology, Lanzhou, China