A high-altitude lithium factory
The Puna Salar Lithium Triangle sits on the Altiplano-Puna Plateau, the world's second-highest plateau after Tibet, with an average altitude of 4,000 meters. This region of the Andes, where Argentina, Chile, and Bolivia meet, is an endorheic basin—a closed system where water flows in but never reaches the sea. All precipitation and meltwater from surrounding mountains collects in vast salt pans, or salars, and can only escape through evaporation. This unique geography is the first requirement for concentrating minerals.
The second requirement is the region's intense volcanic activity. The plateau rests on one of Earth's largest active magma reservoirs. Over millions of years, geothermal and hydrothermal processes have leached lithium from surrounding volcanic rocks, particularly Miocene-Pliocene formations. This lithium-enriched water, often originating from hot springs, flows into the basins. In the arid climate, where evaporation far exceeds rainfall, the water disappears and leaves behind an increasingly concentrated brine. The salars are essentially natural lithium factories, slowly concentrating the element over geological time.
From brine to battery
The lithium is not mined from hard rock but is extracted directly from the brine beneath the salt crusts. This salty water, which can be eight times more concentrated than seawater, is pumped into a series of massive, shallow ponds that spread across the landscape. Here, the intense sun and dry winds do the work. The process is a slow, multi-stage solar evaporation that can take 12 to 18 months. As the water evaporates, different salts precipitate out in a specific sequence, allowing for their separation.
The initial brine may have a lithium concentration between 200 and 1,000 parts per million (ppm). At the Salar de Olaroz in Jujuy, for example, average lithium grades are around 657 mg/l. After months in the evaporation ponds, the concentration can increase to 6,000 ppm. This highly concentrated solution is then processed to produce lithium carbonate, a stable white powder that becomes a fundamental component in rechargeable batteries for phones, laptops, and electric vehicles.
Beyond the geology, these salars are unique ecosystems. The hypersaline, high-altitude environment with extreme temperature swings and high UV radiation, hosts poly-extremophiles. These are microorganisms, primarily bacteria and archaea, adapted to survive conditions few other life forms can withstand. Genera such as Exiguobacterium, Acinetobacter, and Bacillus have been identified in these environments, many showing remarkable resistance to UV radiation.