Coal‐Forming Environment and Provenance Evolution During the Late Permian in Western Guizhou Province: Evidence From Coal Petrography and Geochemistry of Longtan Coal in Well DH ‐1

ABSTRACT The geochemical signatures of trace elements in coal serve as crucial indicators of material sources and depositional environments during its formation. This study focused on 13 coal seams from the Longtan Formation in the Dahebian syncline, Guizhou, China. It involved industrial analysis, sulphur measurement, elemental profiling, coal ash composition analysis, maceral identification and trace element quantification. The research explored petrological, mineralogical, sedimentological and geochemical characteristics of coal samples to evaluate the vertical evolution of coal‐forming environments and variations in provenance within the Longtan Formation. The study investigated relationships between changes in depositional environments and material sources and developed a sedimentary filling model for the late Permian in western Guizhou. Key findings include: (1) The overall depositional environment of the Longtan Formation was predominantly humid and reducing, and the coal‐forming plants were mainly aquatic and herbaceous. However, the depositional environment in the upper segment is more stable than that in the lower segment, with a trend towards arid and oxidative conditions in the later depositional stages. (2) Instabilities in the depositional environment of the lower segment of the Longtan Formation could be attributed to magmatic dike eruptions and volcanic ash fallout from the Emeishan region. The shift towards arid and oxidative conditions during the later stages of deposition in the Longtan Formation might be linked to extensive acidic volcanic eruptions around the periphery of South China towards the end of the late Permian.