Table 1 Variation range and average abundance of trace elements in ZK14-1 drilling core sediments (μg/g)

The variation range and average abundance of trace elements in the ZK14-1 drilling core can be seen as follows: In the 543-568m section, the abundances of trace elements such as Li, Be, Sc, Cu, Zn, Rb, Cs, Pb, Th and U show significant differences from those in the upper and lower strata. All of them are higher than those in the upper strata, while the content of Sr element is lower than that in the upper strata. The sediments in this section have geochemical characteristics different from those in the upper strata. Relative to the abundance of trace elements in sediments of the Chinese mainland The sediment in this hole has relatively high levels of Li (44.6 μg/g), Ga (25.5 μg/g), Rb (142.3 μg/g), Sr (214.6 μg/g), Cs (14.2 μg/g), Th (22.3 μg/g), and U (4.7 μg/g). The sediments slightly higher than those in Chinese mainland include Sc (15.4 μg/g), Y (31.7 μg/g), and Nb (18.5 μg/g), indicating that during the weathering and leaching process, the abundant metal ions such as Rb in the Tatareng rock mass were washed and leached out by atmospheric precipitation, etc. The formed mineral-bearing solution migrated through surface runoff or groundwater. Ultimately, they are enriched in coal-bearing strata, and the lithology of coal-bearing strata mainly includes mudstone, carbonaceous mudstone and coal. These rock layers all have strong adsorption properties and can efficiently adsorb metal cations in the solution to form stable metal-organic complexes, enabling them to stably exist in the strata.