The No. 8 Thick Coal in the Taiyuan Formation, correlated with the Gzhelian (Pennsylvanian, Carboniferous) stage, extends throughout the Ordos Basin and reaches up to 30 m in thickness according to basin-wide seismic profiles analysis. This thick coal bed was formed as long-residence histosols, primarily in ombrotrophic mires with minor development in rheotrophic mires. Analysis of miospore taxa percentages across the thick coal seams identified three consistent bulk characterizing species (bcs): Torispora spp., Laevigatosporites spp., and Florinites spp. These species occur in predictable sequences throughout all No. 8 Thick Coals at both the Palougou outcrop and the Huo10 Borehole. Detailed examination revealed three distinct palynomorph associations in the No. 8 Thick Coal from the Huo10 Borehole: Latosporites globosus Association at the base, Laevigatosporites spp. Association in the middle, and Florinites spp. Association near the top. These associations share similar taxa with the Striatosporites clatratus Biozone and Pachetisporites kaipingensis Biozone previously identified in Carboniferous-Permian transitional deposits at the Palougou Section. This similarity confirms that the No. 8 Thick Coal was deposited simultaneously across the northern Ordos Basin and maintains a consistent, widespread distribution. The widespread presence of trilete and monolete miospores throughout the No. 8 Thick Coal suggests that peat accumulation kept pace with basin subsidence during the Gzhelian in the Ordos Basin. This balance created stable soil conditions that allowed tree ferns to form thick coal layers with consistent bcs. The bcs model in No. 8 Thick Coal differs from the previous Euramerican models in two key aspects: it exhibits prolonged dominance of trilete and monolete miospores and lacks both Lycospora and Densosporites spp. bcs at the coal base and roof. These differences reflect the distinct climate and vegetation of the Cathaysian Palaeofloristic Province during the Pennsylvanian (late Carboniferous), where Psaronius dominated the peat-forming swamp with minor Cordaites presence along its margins. (c) 2025 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS.