Mineralogy and geochemistry of late Permian coals from the Taoshuping Mine, Yunnan Province, China; evidences for the sources of minerals

This paper describes the mineralogy and geochemistry of a batch of 17 coal samples covering the Late Permian Longtan Formation from a drill core from the Taoshuping mine, eastern Yunnan Province, China. The results show that minerals in the coals include quartz, kaolinite, calcite, chamosite, pyrite, mixed-layer I/S and minor marcasite, siderite, anatase, ankerite, and dolomite. Modes of occurrences of authigenic quartz and chamosite suggest that they were mainly precipitated from Fe-Mg-rich siliceous solution derived from the weathering of Emeishan basalt, which was induced by mantle plume eruption during late Middle Permian and covers most places of southwest China. Kaolinite and mixed layer I/S are mainly of detrital origin. Correspondingly, the elevated trace elements, including V, Cr, Co, and Ni, in the coals are closely related to Emeishan basalt. Trace amounts of detrital calcite, ankerite and siderite in the coals probably originated from the Maokou limestone. The frequent presence of high temperature quartz indicates that felsic volcanic eruption took place through the entire Late Permian Epoch. Mineral matter in the coals was not only derived from Emeishan basalt in the Kangdian Oldland, but also felsic volcanic ashes, mafic volcanic ashes, and limestone of the Maokou Formation.