<p>Elemental and Sr isotopic (⁸⁷Sr/⁸⁶Sr) distributions in multiple mineralogical phases of lake sediments are modulated by catchment processes, but their controlling mechanisms and paleoenvironmental indications remain poorly understood. This study employs a 20-step incremental leaching approach to analyze the distribution of elements and ⁸⁷Sr/⁸⁶Sr ratios in carbonate-rich lake sediments. Targeted phases include water-soluble salts (water leaching), exchangeable phase (NH₄Ac leaching), carbonates (incremental HOAc leaching), Fe–Mn oxides (NH₂OH·HCl leaching), chlorite phase (heated HCl leaching), and residual silicates (HF-HNO₃ digestion). Our results reveal that most elements peak in residual silicate phase, while other phases exhibit distinct elemental preferences: Na, K, Ca, Rb and Sr in water-soluble salts; Ca, Sr, Mn, and P in exchangeable phase; Ca, Sr, Mg, Mn and P in carbonate phase; Fe, Mn, Mg, Sr and P in Fe–Mn oxide phase; and K, Fe, Mg, Mn, Rb, Sr and P in chlorite phase. The ⁸⁷Sr/⁸⁶Sr ratios exhibit consistently low values of 0.7111–0.7114 in water-soluble, exchangeable, and carbonate phases (leached by 0.25 and 1% HOAc), then gradually increase to 0.7129–0.7133 through the subsequent extraction of carbonate and Fe–Mn oxides, followed by a sharp increase to 0.7218–0.7263 at chlorite and residual silicate phases. Our study reveals that the elemental and ⁸⁷Sr/⁸⁶Sr data primarily reflect a mixture of authigenic (lake water) and detrital signals. Our results, therefore, suggest that when carbonate is exhausted during leaching, non-carbonate inputs are significant and that the original ⁸⁷Sr/⁸⁶Sr signature of the paleolake water can be uniformly extracted from the water-soluble, exchangeable, and initially dissolved carbonate fractions when diagenetic alteration is carefully considered.</p>