Revisiting the late Permian coal from the Huayingshan, Sichuan, southwestern China: Enrichment and occurrence modes of minerals and trace elements

The major carriers of the rare earth elements in the coal are rhabdophane and silicorhabdophane, the latter of which is also enriched in Zr. Zirconium, however, mainly occurs in zircon. Rhabdophane and silicorhabdophane in the coal are mainly distributed along the bedding planes and occur as cell-fillings. Zircon in the coal occurs as cell-fillings and is of authigenic origin. Anatase in the partings and coals contains Nb, and occurs as fracture-filling and colloidal forms. The modes of occurrence of the above minerals indicate that they were derived from hydrothermal fluids. Mercury and Se mainly occur in sulfide minerals (pyrite and marcasite).