Natural mineral water is not only a kind of valuable mineral resource, but also a water supply source for surface water system (e.g., wet land and riparian zone), which is critical for keeping the biological diversity. A large amount of strontium-rich mineral water has been discovered in the Huangshui River catchment, which originates in Haiyan and Huangyuan, Qinghai Province, with a few springs also containing lithium and metasilicic acid. However, the study on the genesis of threshold-value elements and the related hydrochemical evolution processes are rare. In addition, some sampling points have exceeded the threshold value, which directly affects the development and utilization of mineral water and is an urgent problem that needs to be solved. In this study, the Huangshui River Catchment was considered as a target area. Hydrogeochemical and modeling methods were employed to uncover the hydrochemical features and genesis of mineral water by collecting spring samples from the catchment, which can play an important role in understanding the hydrogeochemical processes within the groundwater system in the Huangshui River Catchment. Most of the groundwater samples in this study area reach the standards of the National Drinking Natural Mineral Water, and all the strontium concentration is higher than 0.2 mg/L with a few samples being rich in lithium and metasilicic acid. The Hydrogeological result shows that the groundwater moving from recharge area to discharge area has a transition of hydrochemical type from HCO3-Ca·Mg to SO4-Na, which is the result of gypsum dissolving in groundwater. The relationships between Sr and the major anions such as HCO3-、SO42- and Cl- show that carbonates have a limited contribution on Sr concentration in groundwater. Instead, the gypsum layers may contain a certain number of Sr-bearing minerals because of the atom exchange between Ca and Sr. Those Sr-bearing minerals are responsible for the high concentration of Sr in groundwater. In terms of the genesis of Li and Si in groundwater, the ancient salt lake sedimental environment may explain the former one and the dissolving of aluminumsilicate minerals may explain the latter. The inverse modeling shows that the groundwater mainly dissolves gypsum, rock salt and illite, while the dissolution of azurite and lithium pyroxene contributes strontium and lithium in the northern catchment. The dissolution of gypsum and halite leads to the high TDS of groundwater in the southern catchment, combined with the dedolomitization process. The whole research findings can serve as scientific basis for exploration and preservation of mineral waters.
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