Lake sediments exhibit compositional heterogeneity related to their formation conditions, including climatic factors. The Urals serve as a climate divide, therefore making research into lake sedimentation conditions (including climatic aspects) particularly relevant in this region. A review of literature indicates that only a small fraction of the numerous lakes in the Urals has been studied. Aim. To analyze elemental composition and geochemical indicators as markers of compositional heterogeneity and genetic characteristics of Lake Turgoyak sediments. Object. Results of geochemical analysis conducted on a 572 cm sediment core from Lake Turgoyak, dating back at least 25000 years BP. Materials and methods. X-ray fluorescence analysis of sediment samples was performed using the Bruker S8 Tiger X-ray fluorescence spectrometer. X-ray fluorescence analysis results were used to calculate geochemical indices based on ratios of elements with high geochemical contrast (CIA, ICV, WIP, PIA, CIW, etc.). Principal component analysis was applied to the chemical composition data to identify key geochemical factors. Results. The study identified the most diagnostic indicators of geochemical stratification in the lake sediment (CIA; (Al, Rb, Mg, Na), (Si, K, Fe, Ti), (Cu, Ni, Zn, Ba), (Br); Mn; LOI₉₅₀), which reflect changes in mobile/immobile element ratios, variations in allogenic input, bioproductivity, and lake water mineralization. Conclusion. Geochemical heterogeneity was observed in the Pleistocene-Holocene sediments of Lake Turgoyak, reflecting the epochal climate transition at the Pleistocene-Holocene boundary and the main stages of lake development during the Holocene.