Lithium and Brine Geochemistry in the Salars of the Southern Puna, Andean Plateau of Argentina

Abstract

The Andean plateau is a small region of South America extending between northwest Argentina, southwest Bolivia, and northern Chile. It concentrates the largest global resources of lithium brines in its numerous salars. Of these, the giant salars in Bolivia and Chile have been relatively well studied; however, only little is known about the smaller but numerous salars in the Argentine Puna region. In this article, we present the results of the first regional-scale reconnaissance exploration of the 12 major salars situated in the southern part of the Puna plateau (24°S–26°30’S). Hydrochemical data indicate that the shallowest brines are characterized by highly variable Li concentrations, with mean Li grades ranging between 57 and 570 mg L−1, and mean Li/Mg ratios from 0.01 to 1.24. A survey of the brine chemistry of the salars across the Puna plateau, including its northern part, has revealed the absence of a geographical pattern in Li+ grade distribution. However, a comparison among mean Li+ grades, Li+/Mg2+ ratios, and the sizes of all salars allows an estimation of their Li mining potential. Specifically, the salt pan of Arizaro represents the highest potential, mainly due to its size; Antofalla-Botijuelas has a large surface and promising Li/Mg ratios for Li recovery via brine evaporation, though its elongated shape is a constraint; and Pastos Grandes, Pozuelos, and Rincón have encouraging Li grades, interesting salar sizes, and relatively easy access. Olaroz, Cauchari, and Hombre Muerto contain the highest Li+ grades in brines of the Argentine Puna and embody the most interesting perspectives of the Argentine plateau in a regional context. Salar sizes could be related to maximum Li+ grade of brines. Larger salars would then be expected to contain brines with higher Li+ grades than smaller ones, which could be considered as a useful criterion for surveys of brine-type deposits.

Brine grades in Andean salars: When basin size matters A review of the Lithium Triangle

“…Summarized data for the Puna de Atacama salars follow Risacher et al (1999;summarized by COCHILCO, 2013), excepting for samples LAC0, SUR0, HCO0, ASC0, ATA0, ATAdo, and AZU0 that are from Ericksen and Salas (1987). Brine chemistry of the Puna salt pans follows data reported by López Steinmetz (2017), López Steinmetz et al (2018), and López Steinmetz et al (2020a), excepting for samples CE0, HM0, PG0, AR0, PC0, RI0, and RG0 that are from Ericksen and Salas (1987). TDS in g L -1 , remaining concentrations in mg L -1 .…”

“…Amongst the Puna salt pans, only Hombre Muerto and Olaroz are being actively mined for Li. The brine chemistry in the Puna salars has been characterized by López Steinmetz et al (2018) and López Steinmetz et al (2020a). These brines contain highly variable saline content and ionic proportions.…”

“…Journal Pre-proof -126 brine samples from the Puna salt pans (Ericksen and Salas, 1987;López Steinmetz, 2017;López Steinmetz et al, 2018;García et al, 2019;López Steinmetz et al, 2020a), and -173 brine samples from the Puna de Atacama salt pans reported by Moraga et al (1974), Vila (1975), Salas (1987), andRisacher et al (1999;summarized by COCHILCO, 2013).…”

Understanding the Spatial Variation in Lithium Concentration of High Andean Salars Using Diagnostic Factors

“…Excluding (6), Munk et al (2016) elaborates how these parameters may be implemented to help lithium ore exploration features on a global scale. They present and discuss eighteen basins that share these parameters, however how each of these characteristics are correlated with respect to lithium evolution has not yet been fully explored (Munk et al, 2016), accordingly variation in the spatial regional lithium concentrations pattern have not been fully developed (López Steinmetz et al, 2020). An example of such a case is the significant variation of lithium concentration between the Salar de Atacama and Salar de Guayatayoc with Li ≈ 1400 and ≈100 mg/l, respectively (López Steinmetz et al, 2020).…”

Trace Elements and Mineralogy of Upper Permian (Zechstein) Potash Deposits in Poland

“…Brines of the Salar de Atacama in Chile, which is two times smaller, contain 1000-7000 mg/L [23] or 1000-5000 mg/L of lithium (average-1400 mg/should be "L" -the symbol of "litre"), and in in 2017 they represent 27% of the world reserves [6,24,25]. Brines of salars in Altiplano have from 57 to 570 mg/L up to 8.9 g/L of lithium and 10.8 g/L of boron [26][27][28][29]. Brines of Quarham saline lake (Quaidam Basin, western China) contain 51.6-138.4 mg/L of boron [30].…”