Exploring rare earth elements in Northern Kazakhstan: The potential of ion-adsorption clays and coals as unconventional sources
Junussov M. Kembayev M.K. Kokkuzova M. Baisalova A. Umarbekova Z.T. Abirov R. Rais S.E. Amantayev A.
2025Science Press
Acta Geochimica
2025
This study presents the first integrated mineralogical and geochemical investigation of unconventional rare earth elements (REEs) in ion-adsorption clay (IAC) from the weathered granitic complex of Souktal and coal-derived samples from Saradyr and Bogatyr mines in Kazakhstan. Six representative samples were analyzed using mineralogical, geochemical, and petrographic methods, along with CIA/CIW (chemical index of alteration/weathering), and elemental ratios to assess weathering intensity and provenance. Results show that REEs in IAC samples are primarily adsorbed onto kaolinite and likely apatite under mildly acidic conditions (pH 4.8–5.0), with high CIA/CIW values (> 93.2) indicating advanced weathering. In coal ash, REEs are mainly hosted in organic matter and phosphate minerals, showing a strong correlation with organic carbon, while CIA/CIW values (> 62.8) indicate moderate to high weathering intensity. Provenance analysis indicates felsic sources for IAC and mixed mafic–intermediate for coal-derived samples. Although Coutl values (1.1–1.7) are promising, total REEs concentrations remain below 10 ppm, suggesting subeconomic potential. The findings reveal that all samples from the studied deposits are characterized by high weathering under arid climatic conditions, exhibiting an enrichment pattern similar to underdeveloped global analogs. This reflects a complex interplay between weathering intensity, regolith development, coalification dynamics, sediment source, hydrology, and organic-phosphate host phases in controlling REEs distribution. REEs enrichment in both IAC-type and coal-hosted deposits is influenced by arid-zone supergene processes and coastal plain diagenetic pathways. Future research should target deeper weathered regoliths in IAC systems and surrounding coal seam rocks, using advanced analytical and stratigraphic tools to clarify REEs speciation and the influence of paleoclimate and tectonics on their accumulation in North Kazakhstan.
Coal , Ion-adsorption clay , Kazakhstan , Rare earth elements , REEs
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Faculty of Mining and Geosciences, School of Mining and Geosciences, Nazarbayev University, Astana, 010000, Kazakhstan
Institute of Geology and Oil-Gas Business, Satbayev University, Almaty, 050013, Kazakhstan
Institute of Geological Sciences Named After K.I. Satpayev, Almaty, 050010, Kazakhstan
Quantum Planetoid Resources TOO, Almaty, 041626, Kazakhstan
Faculty of Mining and Geosciences
Institute of Geology and Oil-Gas Business
Institute of Geological Sciences Named After K.I. Satpayev
Quantum Planetoid Resources TOO
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026