1. School of Geosciences and Info-Physics, Central South University, Changsha, Hunan 410083, China
2. Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Central South University, Ministry of Education, Changsha, China
3. Faculty of Science, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
4. School of Mathematics and Statistics, Central South University, Changsha, Hunan 410083, China