Identification and classification of fine-grained sedimentary fabrics in coal measures: A case study from the northwestern Dongsheng Coalfield

Based on detailed analyses of fine-grained sedimentary characteristics and rock assemblages in coal measures, as well as correlations between macroscopic and microscopic sedimentary components, this study systematically investigates the types of fine-grained sedimentary fabrics in coal-bearing strata. A combination of macroscopic description, petrographic characterization, experimental analyses, and maceral identification was employed to classify the fabrics. According to mineralogical composition—particularly the abundance of key minerals—together with textural attributes and sedimentary structures, the fine-grained sedimentary fabrics of the coal measures are classified into carbonaceous clayey fabric, siliceous-clayey mixed fabric, organic-clayey composite fabric, and clayey silty fabric. On this basis, the lithofacies associations of the coal measures, the dominant sedimentary facies, and their spatial and temporal variations are further analyzed. The results demonstrate that systematic characterization of fine-grained sedimentary fabrics in coal measures is of considerable significance for reconstructing the paleogeography of coal-forming basins and for evaluating the reservoir potential of fine-grained sedimentary rocks.