A 4,200-meter high chemical factory
The Salar de Surire sits at an elevation of over 4,200 meters (13,776 feet) in the Andean highlands of northern Chile. This endorheic basin, a closed drainage system, collects water and sediments from surrounding extinct volcanoes. Intense solar radiation and dry winds drive extreme evaporation, concentrating dissolved minerals into a vast, shimmering salt crust. The total area of the basin is 140 square kilometers.
The salar contains one of the world's largest deposits of ulexite, a borate mineral with the chemical formula NaCaB₅O₆(OH)₆·5H₂O. Ulexite forms in silky white, fibrous masses. These natural fibers possess an unusual optical property that gives the mineral its nickname "TV stone." When a polished piece is placed on an image, the fibers act like parallel light pipes, transmitting the image from the bottom surface to the top. This phenomenon is a result of total internal reflection along the length of each individual crystal fiber. Borax and other borate compounds are mined here commercially for use in detergents, cosmetics, and fertilizers. The Chilean company Quiborax has been operating a mine in the salar since 1986.
An ecosystem of extremes
Despite the harsh conditions—temperatures can swing from -15°C at night to 5°C during the day—the Salar de Surire supports a specialized ecosystem. The shallow, saline lagoons lagoons are ideal feeding grounds for three of the world's six flamingo species: the Andean flamingo (Phoenicoparrus andinus), James's flamingo (Phoenicoparrus jamesi), and the Chilean flamingo (Phoenicopterus chilensis). These birds use their specialized beaks to filter-feed on diatoms and other microorganisms that thrive in the mineral-rich water. The carotenoid pigments in their food are responsible for the flamingos' distinctive pink coloration.
The area surrounding the salt flat, protected as the Salar de Surire Natural Monument, also contains herds of vicuñas (Vicugna vicugna), a wild relative of the llama. Other resident animals include the Darwin's rhea (Rhea pennata), a large flightless bird locally known as the suri, which gives the salar its name. The landscape is also dotted with high-altitude wetlands called bofedales, which are peat bogs that provide important grazing for the region's herbivores. The overlap between the 11,298-hectare protected monument and active borax mining concessions creates an ongoing tension between conservation and industry.