Chemical and mineralogical compositions of silicic, mafic, and alkali tonsteins in the late Permian coals from the Songzao Coalfield, Chongqing, Southwest China

Shifeng Dai, Xibo Wang, Yiping Zhou, James C. Hower, Dahua Li, Wen‐Mei Chen, Xingwei Zhu, Jianhua Zou

State Key Laboratory of Coal Resources and Safe Mining　China University of Mining and Technology - Beijing　University of Kentucky　Chongqing Institute of Geology and Mineral Resources