# Lithium Concentrations in Saline Brines of the Shu-Sarysu Depression
## 6 Conclusions  
The main objective of the conducted research was to determine the lithium content in the sorts of the lower reaches of the endorheic rivers Shu and Sarysu, with the aim of identifying a new geological-industrial type of lithium deposits as hydromineral raw materials. The obtained results clearly indicate the presence of Li in varying concentrations (from non-commercial to commercial) in all the studied sorts, suggesting a high potential for lithium content in the sorts of the Shu-Sarysu Depression. However, these data also show an extremely uneven distribution of Li in the investigated sorts. Figure 10: Concentrations of potassium, calcium, magnesium, and average lithium values in brines. Figure 9: Lithium content comparison in brines detected by ICP-AES and ICP-MS. Despite the limited scope of the research on the salt flats of the endorheic rivers Shu and Sarysu, the unequivocal data obtained indicate that the most promising area for the localization of lithium mineralization in near-surface brine is the group of salt flats in the lower reaches of the Sarysu River. This fact supports the idea of the migration of dissolved alkali metals along the Sarysu River and their precipitation in its lower reaches, where extensive salt flats have formed. Additionally, in this area, there is supplementary recharge of near-surface waters by formation groundwater through faults, further increasing mineralization. The possible horizons for the spread of lithium brines are Neogene-Quaternary deposits, whose thickness varies between 15 and 30 m.  
The higher lithium content in the group of sons in the lower reaches of the Sarysu River compared to other tested sons in the region may also be linked to the fact that, according to [PERSON] [11], underground brines in the aquifers of the Caspian Lowland, the Shu-Sarysu Depression, and most of Mangystau and Ustyurt are characterized by increased mineralization of 50-400 g/L. The undeniable potential of the sons in the lower reaches of the Sarysu River can be clearly judged by the scheme of lithium geochemical halos of these salt flats (Figure 11). The scheme clearly shows that, based on current knowledge, the most promising sons are in the western and southern parts of the studied area. Additional sampling is required in the anomalous areas to confirm the high Li concentrations. Areas with low Li concentrations require further sampling on a denser grid. In addition to the significant prospects for lithium content in the group of sons in the lower reaches of the Sarysu River, it is also important to consider the presence of isolated high Li concentrations and the presence of lower but still notable Li concentrations in all samples from the sons in the lower reaches of the Shu River, which have been less studied compared to those of the Sarysu. Therefore, if additional work in the salt flats of the Shu reveals an increase in the number of samples with industrially significant Li concentrations (>10 mg/L), the productive Li area could amount to approximately 1800 km\({}^{2}\). These data allow the authors to consider the Chu-Sarysu province as a whole to be promising for the identification of lithium-bearing salt flats. The areas with high and consistent Li concentrations in the samples from the salt flats in the lower reaches of the  
Figure 11: Satellite image with water sampling points in salt marshes in the lower reaches of the Sarysu River. Sarysu River are recommended for exploratory work. In conclusion, the authors would like to emphasize that the work on assessing the lithium content in the sors of western Kazakhstan should undoubtedly be continued to achieve the goal of identifying industrially significant lithium-bearing sors. The results of the authors' initial research fully justify the expansion of exploratory work in this direction. Conceptualization, R.T.B. ; software, M.A.M., V.N.K. and D.O.D. ; investigation, R.T.B., E.Z.M., D.O.D., M.A.M., V.N.K. and N.S.S. ; resources, R.T.B., E.Z.M., D.O.D, V.N.K. and N.S.S. ; writing--original draft preparation, E.Y.S.