Mineral weathering and groundwater flow in Spring Mountains Springs

The groundwater flow system in the Spring Mountains, NV is poorly understood because of a disconnect between structural and topographic contours. We coupled field measurements of groundwater spring temperature and conductivity with water stable isotopes to better understand groundwater circulation patterns. In addition, we paired strontium isotope ratios (87Sr/86Sr) with groundwater geochemistry to identify sources of solutes and to better understand groundwater flow paths through the Spring Mountains. The Spring Mountains geology and groundwater flow system are controlled by a series of large scale thrust faults that separate three distinct rock types: pervasive Permian dolomites, Mesozoic sandstones, and Cambrian shales. Geochemical models we developed suggest that groundwater can be separated into three categories, distinguished by the dominant geology. Modeling results highlight the influence of distinct mineral groups: carbonates, silicates, and evaporites, which help to inform local variation. Furthermore, published strontium isotope ratios of rocks and minerals vary throughout the study area and provide insight into potential groundwater flow paths through measured values of groundwater spring strontium ratios. We are expanding this analysis through the collection of additional rock specimens for strontium isotope measurements, which will further constrain the relationship between rock and spring water geochemistry and provide insight into groundwater flow paths and mineral weathering sources. Study results will help differentiate local and regional flow systems and further understanding of groundwater resilience in the Spring Mountains