Identification and Modeling of Hydrogeochemical Processes in an Arid Zone of Mexican Highlands

Abstract

The study area is located in northern Mexico, within the hydrological region called “El Salado.” This area has low rainfall of 200–350 mm/year and a high evaporation potential of 1896.9 mm/year. In this region, the water is made of sodium bicarbonate due to the interaction with volcanic rocks rich in sodium feldspars and sodium sulfates and can be associated with the dissolution of evaporitic rocks (gypsum) and ionic exchange with sodium clays. Hydrogeochemical diagrams indicate that groundwater follows three main evolutionary trajectories, the first circulating in carbonate materials; another involves the alteration of silicates and the third evolutionary path shows the processes of alteration of silicates, ion exchange, and evaporation. The groundwater of the aquifer shows saturation of minerals such as dolomite, calcite, chalcedony, and magnetite that is consistent with the evolution of groundwater. The infiltration of water enriched with CO₂ reacts with albite and K feldspar, releasing silica, Na⁺, K⁺, Mg²⁺, and HCO₃⁻ and the formation of clays. Reverse modeling indicates the formation of calcite, hematite, alteration of magnetite, and dissolution of gypsum.