Occurrence Patterns and Enrichment Influencing Factors of Trace Elements in Paleogene Coal in the Fushun Basin, China

The occurrence forms of trace elements in coal are of great significance for the clean utilization, abnormal enrichment, and recovery of beneficial elements in coal. The Fushun Basin in Northeast China has thick coal deposits which provide a good opportunity for studying their geochemistry. This study aims to estimate the element enrichment of Paleogene coal seams and their influencing factors during deposition based on statistical and geochemical analyses. Compared with world hard coals, coals in the Fushun Basin feature enrichment of Ga and Sb (CC > 5), slight enrichment of V, Cr, Co, Ni, As, Rb, Zr, Nb, and Cd (2 < CC < 5), and depletion of B, Tl, Bl, and U (CC < 0.5). The CC values of the remaining elements (0.5 < CC < 2) are close to the average values for world hard coals. The main carriers of Ga, Co, Rb, Mo, As, Se, Pb, V, and Li are potassium, iron, and sulfate minerals and those of Cd, Cr, Ni, Sb, Th, Sn, U, Hf, Zr, Cs, Ta, and Nb are clay minerals. The CIA, Sr/Cu, Rb/Sr, and Ga/Rb values suggest that the studied coal seam formed under humid/warm climatic conditions. The coal seam is mainly derived from intermediate source rocks and sandstone or mudstone source rocks which were exposed to intensive chemical weathering and deposited in a freshwater setting. Additionally, paleoweathering, paleoclimate, detrital input, and provenance all contributed to the enrichment of geochemical elements in the studied Paleogene coal. The results of this study are preliminary, and the authors will continue to conduct mineralogical analysis.