Hydrogeochemical fluxes and processes contributing to the formation of lithium-enriched brines in a hyper-arid continental basin

摘要: Abstract The accumulation of solutes delivered via shallow groundwater and surface water in arid to hyper-arid closed basins, the complex hydrogeochemical processes associated with their transport, are key deciphering mechanisms responsible for formation brines salts these environments. A rigorous investigation fluxes Li-enriched brine basin Salar de Atacama, Chile is presented. Water within Atacama range from 0.003 m3/s 1.50 m3/s a poor correlation between discharge drainage area. inflowing waters have major elemental Li concentrations that same order magnitude over period several decades. element indicate, example, 58% halite nucleus derived south southeast parts basin. average δ18Ovsmow δDvsmow inflow indicate there varied sources recharge corresponding defined sub watershed regions. flux-weighted 87Sr/86Sr allows further definition where regional derived. predicted flux weighted (0.70813) compared measured (0.70801), indicates may be unaccounted brines. Elemental time scales volume balance on frames 0.5 Ma (Mg), 1.0 Ma (Ca), 1.9 Ma (Li) 2.2 Ma (K) as 47 Ma (Na) 53 Ma (Cl), evidence Na Cl require additional not accounted modern inflows topographic watershed. Dissolved noble gas marginal specify formed an atmospheric equilibrated state since been isolated below salt crust. process-based model presented explain extremely high which incorporates δ7Li isotope signatures decipher, first order, contributions such low temperature weathering secondary phase formation.