Distribution of Selected Trace Elements and Mineralogical Features of the Kislakoy Coal-Seam Profile, Afsin-Elbistan Basin, Turkiye

Abstract

In the Afsin-Elbistan coal seam in T & uuml;rkiye, this study investigates the vertical distribution, enrichment features, and mineralogical controls of trace elements and rare earth elements (REEs). Thirty coal samples were collected vertically from the K & imath;slakoy open-pit mine. Major oxide concentrations were determined by XRF for 29 samples, whereas trace element concentrations were determined by ICP-MS for all 30 samples. Mineralogical and textural characteristics were investigated in 15 selected samples by XRD and SEM-EDS. The coal is abundant in quartz, pyrite, and gypsum, along with trace amounts of calcite, clay minerals, and feldspars, which demonstrate the combined effects of detrital input, reducing depositional conditions, and post-depositional alteration. The major oxide composition is dominated by SiO2, CaO, Al2O3, and Fe2O3, showing notable contributions from carbonate, aluminosilicate, and Fe-bearing mineral phases. Most trace elements occur at levels close to the world coal average, whereas V, Ni, and U are significantly enriched, and Cr and Co are slightly enriched. Total REE contents range from 21 to 125 ppm, averaging 51 ppm, and display light REE enrichment over heavy REEs. Weak negative Ce anomalies and slight positive Eu anomalies indicate variable redox conditions and the influence of terrigenous mineral input. Vertical distribution patterns indicate that during peat accumulation and early diagenesis, variations in detrital input, mineral matter abundance, and depositional redox conditions regulated trace element and REE distributions. REEs are mainly associated with aluminosilicate and locally phosphate-bearing phases, whereas V, Ni, and U are linked to organic matter and/or sulfide-rich intervals. These results show that the main factors influencing trace-element and REE behaviour in the Afsin-Elbistan coal seam are the mineralogical composition and redox evolution.