Salar de Uyuni: Daniel Campos, Bolivia
The reflective surface of the world's largest salt mine is like something from the imagination of Salvador Dali—although we're happy it actually exists in real life.
Salar de Uyuni is part of the Altiplano of Bolivia in South America. The Altiplano is a high plateau, which was formed during uplift of the Andes mountains. The plateau includes fresh and saltwater lakes as well as salt flats and is surrounded by mountains with no drainage outlets.[9]
The geological history of the Salar is associated with a sequential transformation between several vast lakes. Some 30 000 to 42 000 years ago, the area was part of a giant prehistoric lake, Lake Minchin. Its age was estimated from radiocarbon dating of shells from outcropping sediments and carbonate reefs and varies between reported studies. Lake Minchin (named after Juan B. Minchin of Oruro[10]) later transformed into Paleo Lake Tauca having a maximal depth of 140 meters (460 ft), and an estimated age of 13 000 to 18 000 or 14 900 to 26 100 years, depending on the source. The youngest prehistoric lake was Coipasa, which was radiocarbon dated to 11 500 to 13 400 years ago. When it dried, it left behind two modern lakes, Poopó and Uru Uru, and two major salt deserts, Salar de Coipasa and the larger Salar de Uyuni. Salar de Uyuni spreads over 10 582 km2, which is roughly 100 times the size of the Bonneville Salt Flats in the United States. Lake Poopó is a neighbor of the much larger Lake Titicaca. During the wet season, Titicaca overflows and discharges into Poopó, which, in turn, floods Salar De Coipasa and Salar de Uyuni.[11]
Lacustrine mud that is interbedded with salt and saturated with brine underlies the surface of Salar de Uyuni. The brine is a saturated solution of sodium chloride, lithium chloride, and magnesium chloride in water. It is covered with a solid salt crust varying in thickness between tens of centimeters and a few meters. The center of the Salar contains a few islands, which are the remains of the tops of ancient volcanoes submerged during the era of Lake Minchin. They include unusual and fragile coral-like structures and deposits that often consist of fossils and algae.[12]
The area has a relatively stable average temperature with a peak at 21 °C in November to January and a low of 13 °C in June. The nights are cold all through the year, with temperatures between −9 °C and 5 °C. The relative humidity is rather low and constant throughout the year at 30% to 45%. The rainfall is also low at 1 mm to 3 mm per month between April and November, but it may increase up to 80 mm in January. However, except for January, even in the rainy season the number of rainy days is fewer than 5 per month.[8]
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