Salars with lithium-rich brines are a characteristic feature of the Central Andes, but knowledge about the main sources of lithium and the mobilization processes of lithium in the salar deposits is still incomplete. This work focuses especially on the Salar de Diablillos (southern Puna) as part of a larger area that includes the neighboring Salar Centenario and Salar de Ratones. Building on the ability of Li as a tracer of silicate weathering, we investigate the Li content and isotope composition of samples from the depocenter and catchment of the Diablillos basin (3-D) and conduct a surface reconnaissance in the Centenario and Ratones depocenters to identify the key metallogenic processes. Radiogenic Sr and Nd isotope compositions are also provided to discriminate the main local Li sources. The isotope data in all three depocenters show that most of the Li in the brines and evaporite deposits are derived from Cenozoic volcanic rocks, despite the dominance of the Paleozoic basement in the catchment. In the Centenario and Ratones depocenters, near-surface chemical weathering appears to be the dominant Li mobilization process. In contrast, hydrothermal mobilization of Li also plays a role in the Salar de Diablillos, possibly related to the presence of a fractured basement with pressure zones and artesian conditions in the aquifer at depth. These fluids also show a larger element contribution from the basement.

Lithium (Li)-rich continental brines found in the Lithium Triangle region in South America are a natural resource of paramount importance. In the present research, the analytical performance of laser-induced breakdown spectroscopy (LIBS) technology was assessed for the quantitative analysis of Li in natural brines aimed at enhancing the efficient exploration of salt flats (called salars). Brine samples were collected from different salars located in the Puna plateau (Northwest Argentina) and analyzed by LIBS in the form of solid pressed pellets. Broadband emission spectra (180–900 nm) were recorded and spectrally analyzed by specially designed computational algorithms. The laser-induced plasmas were characterized by calculating the electron density and the temperature. The Li elemental concentrations in the brines were determined through univariate calibration with the Li I emission line at 670.77 nm by using a suitable set of standards with Li concentrations up to 1300 $\mathsf{\mu }$g/g. The calculated limit of detection was LoD = 0.2 ± 0.1 $\mathsf{\mu }$g/g. The Li content in the brines determined with LIBS showed a good agreement (normalized standard deviation: σ_N = 25%) with the concentrations measured with atomic absorption spectroscopy. The results demonstrated the feasibility of the LIBS technique for the quantitative analysis of Li in natural brines, thus contributing to advancing the exploration of Li-rich resources.