基金supported by the China Geological Survey(No.1212011121261)the National Natural Science Foundation of China(Nos.41272053and41072030)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20110145110001)the Independent Research Project Foundation of State Key Laboratory of Biogeology and Envi-ronmental Geology,China University of Geosciences,Wuhan(No.GBL11307)