Evaporites are widely distributed within continental “red beds” in the Lanping–Simao Basin, west Yunnan, China. Sr (Strontium), S (Sulfur), and O (Oxygen) isotope compositions have been measured on 54 sulfate or/and sulfate-bearing samples collected from Lanping, Nuodeng, Jinggu, Mengyejing, Baozang throughout the Lanping–Simao Basin. The ⁸⁷Sr/⁸⁶Sr ratios of all samples (0.708081 to 0.710049) are higher than those of contemporaneous seawater, indicating a significant continental contribution to the drainage basin. Sulfates in the Lanping Basin have higher ⁸⁷Sr/⁸⁶Sr ratios (0.709406 to 0.710049) than those (0.708081 to 0.709548) in the Simao Basin. Nevertheless, the δ³⁴S values of gypsums (13.4‰ to 17.6‰) in Lanping and Baozang fall within the range of Cretaceous seawater. Gypsums from a single section in Baozang have trends of decreasing δ³⁴S values and increasing ⁸⁷Sr/⁸⁶Sr ratios from base to top, indicating continental input played an increasingly significant role with the evaporation of brines. High δ³⁴S values (20.5‰ to 20.7‰) of celestites in Lanping are probably caused by bacterial sulfate reduction (BSR) process in which ³⁴S were enriched in residual sulfates and/or recycling of Triassic evaporites. The reduced δ³⁴S values of gypsums (9.5‰ to 10.4‰) in Nuodeng could have been caused by oxidation of sulfides weathered from Jinding Pb-Zn deposit. The complex O isotope compositions indicate that sulfates in the Lanping–Simao Basin had undergone sulfate reduction, re-oxidation, reservoir effects, etc. In conclusion, the formation of continental evaporites was likely derived from seawater due to marine transgression during the Cretaceous period. Meanwhile, non-marine inflows have contributed to the basin significantly.

The homogenization temperature (Th) of primary fluid inclusions in halite can be used for paleoclimate interpretations. Lop Nur, in Central Asia, is an extremely arid zone where large amounts of glauberite were deposited from the late Middle to Late Pleistocene. This deposition was accompanied by formation of large-scale potash-bearing brines. However, quantitative paleotemperature data are still lacking, hindering reconstruction of Quaternary climate conditions and their control over potash formation. We measured the Thof inclusions in halite from the salt field and the top of Upper Pleistocene strata in Lop Nur. The maximum homogenization temperature (Th_MAX) of inclusions in halite from the salt field was 41.1 °C, consistent with the maximum ambient temperature (43.4 °C) in the same period. The Th_MAXof inclusions in halite from the Upper Pleistocene strata ranged from 35.6 °C to 43 °C, where maximum air temperatures may have reached 37.9 °C to 45.3 °C. The results show that a hot and arid climate prevailed in Lop Nur at the end of the Late Pleistocene. Furthermore, changes of the brine chemical composition due to supply variations instead of climate change, may have caused glauberite deposition to cease at the end of the Late Pleistocene.

Qarhan Salt Lake, China’s largest brine-type potassium-lithium deposit, holds substantial economic value. However, the timing of lithium-rich brine formation, its origin, and the role of climate in its development remain unclear. This highlights the need for a deeper understanding of salt lake evolution, particularly regarding ore-forming brine composition and the palaeoclimate. Therefore, we conducted ²³⁰Th dating on halite deposits from borehole ZK6-7 (7.5–46.7 metres) in the northern Bieletan, revealing halite deposition at 237.79–30.29 thousand years before 2000 A.D. The maximum homogenisation temperature of fluid inclusions was 23.9–41.7 °C, indicating frequent palaeobrine temperature fluctuations, corresponding to palaeoclimatic events in the Qinghai–Tibet Plateau and Qaidam Basin. Lithium, potassium, magnesium, boron, and bromine concentrations were inversely correlated with the maximum homogenisation temperature. Lithium-rich brine formation in the Bieletan was a long-term process driven by interglacial-glacial cycles, where warm periods increased river flow and material supply, while dry-cold periods intensified evaporation, promoting mineral enrichment.