Multi-isotopic composition (Li and B isotopes) and hydrochemistry characterization of the Lakko Co Li-rich salt lake in Tibet, China: Origin and hydrological processes

• Published in: Journal of hydrology (Amsterdam) 2024-02, Vol.630, p.130714, Article 130714
• Main Authors: Li, Zhengyan, He, Mao-Yong, Li, Binkai, Wen, Xueqin, Zhou, Jiangdi, Cheng, Yuanyuan, Zhang, Ning, Deng, Li
• Format: Article
• Language: English
• Subjects: Boron isotope; Hydrochemical Characteristics; Lakkor Co salt lake; Lithium isotope; Lithium-rich Salt Lake; Source
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2024.130714

[Display omitted] •Li-B isotopes analysis is a useful method to determine the source of ore-forming elements in Li-rich salt lakes.•The occurrence of secondary mineral precipitation leading to a decline in the values of δ7Li and δ11B.•Magnesite deposited at Lakko Co (sulfate type), influences the B isotope value, while having no effect on Li isotope value.•Hydrochemistryand Li-B isotopes reveal rock weatheringand geothermal fluids as potential B and Li sources in the Lakko Co. A comprehensive comprehension of the origin and ore-forming process of lithium brine deposits is imperative prior to engaging in lithium resource exploration, development and utilization. Nevertheless, the provenance of lithium in salt lakes has always been controversial. The lithium and boron (Li and B) isotopes, which serve as discerning geochemical tracers, can facilitate the monitoring of geological processes and sources. In this study, we investigated the hydrochemistry, Li and B isotope characteristics of surface brine and recharge river samples collected from the Lakko Co on the Qinghai-Tibet Plateau in China. The dissolved Li concentrations range from 0.11 to 590.8 mg/L, δ7Li and δ11B values exhibit a range of 0.75∼8.11 ‰ and -18.29∼-4.01 ‰, respectively. Concentrations of elements such as Rb, and Cu are relatively high and exhibit a strong correlation with Li. Ions composition and content ratios indicate the deep origin of Li and B. The analysis of δ7Li and δ11B suggests that, apart from hot spring, weathering of surrounding rocks also contributes to the presence of Li and B. Besides, variations in δ11B values within the lake brine analysis may be attributed to the deposition of water Magnesite at the lake bottom. The findings suggest that the recharge water system and hot springs serve as the primary source of Li and B in Lakko Co. Additionally, the interaction between water and rock in the deep crust as well as chemical weathering in the shallow environment, significantly contribute to formation of Li-rich fluids. The transportation process is characterized by the precipitation of secondary mineral, resulting in an increase of δ7Li and δ11B. Furthermore, the presence of water Magnesite in the lake brine leads to fluctuations in δ11B. This investigation of the lake contributes to a more comprehensive understanding of the origins and mechanisms involved in the transportation and storage of lithium in lithium-rich salt lakes.