• Li is enriched in the Liangshan Formation claystones, Guizhou, South China. • Li grade is higher where the underlying strata are carbonate rocks rather than clastic rocks. • Li enrichment in the Liangshan Formation was sourced from the underlying carbonate rocks. • Lithium is mainly incorporated in clay minerals such as illite and chlorite as lattice substitution and interlayer adsorption. Lithium (Li) is a critical strategic mineral resource, and sediment‑hosted clay‑type Li deposits have become a major frontier in global Li exploration. This study focuses on Li enrichment in Permian Liangshan Formation claystones in the Puyi area, northwestern Guizhou, South China, using integrated mineralogical and geochemical datasets to constrain enrichment characteristics, material source, depositional conditions, and ore‑forming mechanisms. The Li enrichment is concentrated near the unconformity at the base of the Liangshan Formation, with significantly higher Li grades where the underlying strata are carbonate rocks rather than clastic rocks. Lithium‑rich claystones formed in a freshwater terrestrial to brackish marine‑continental transitional environment, under relatively closed, anaerobic‑reducing conditions, in a tropical–subtropical warm and humid paleoclimate. X‑ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and laser ablation ICP‑MS analyses reveal that illite and chlorite are the primary Li‑bearing minerals, with Li occurring mainly as lattice substitution and interlayer adsorption. Chondrite‑normalized rare earth element (REE) patterns, primitive mantle‑normalized trace‑element spider diagrams, and Li isotopic compositions (δ 7 Li = +1.92‰ to +3.10‰) of the Liangshan Formation claystones are highly comparable to those of the underlying Cambrian Loushanguan Formation impure dolomites, indicating that Li was mainly sourced from the Li‑rich dolomites of the Loushanguan Formation. Intense chemical weathering and burial diagenesis promoted the release, migration, and fixation of Li in clay minerals, leading to significant Li enrichment. This study provides systematic mineralogical and geochemical constraints on Li enrichment in the Liangshan Formation claystones, clarifies the Li source and enrichment mechanism, and offers a scientific basis for exploring sediment‑hosted clay‑type Li deposits in similar geological settings.
ZHANG et al. (Fri,) studied this question.