| Salar de Gorbea | |
|---|---|
 Salar de Gorbea (white) from space | |
| Location | Chile, Atacama Region |
| Coordinates | 25°25′S68°40′W / 25.41°S 68.67°W |
| Surface elevation | 3,946 metres (12,946 ft) |
Salar de Gorbea is a salt flat just south of the border between the Antofagasta and Atacama regions, within Chile but close to the border with Argentina.
Salar de Gorbea lies at the margin of the Puna and the Atacama Desert. [1] It covers a surface area of 32 square kilometres (12 sq mi) and lies at an elevation of 3,944 metres (12,940 ft), [2] in an area where access is difficult. [3] The salt flat has an irregular shape, a square-shaped southern basin with an irregularly shaped bay to the northeast. [4] Salar de Gorbea features both salty sediments, a salt crust and water-filled ponds. [5] The crust is about a metre thick, [6] contains liquid brine [7] and is largely covered by gypsum crystals. A gypsum deposit has formed at the northeastern margin of Salar de Gorbea. [8] Despite the name, the salt crusts are not flat, but have a topography of about 2 metres (6 ft 7 in) [9] formed by e.g. wind-formed dunes. [10]
At some points, saltwater crops out in depressions, forming seven lakes up to a metre deep [11] with various colours, [10] which contain gypsum crystals [12] The ponds may have formed through the dissolution of salt [5] and through wind-driven erosion. [9] Their water is, unusual for the region, [11] acidic, probably due to the high availability of sulfur which yields sulfuric acid and the exhaustion of the buffer capacity of the rock. [13] The total water surface is about 0.5 square kilometres (0.19 sq mi). There are diffuse springs at the margins of Salar de Gorbea. [11] Water reaches Salar de Gorbea mostly from the east in the form of small creeks. A 15 kilometres (9.3 mi) long tributary joins Salar de Gorbea from the south. [2]
Salar de Gorbea contains gypsum as the main salt, [11] crystals are up to 30 centimetres (12 in) long. [5] Thenardite occurs at its southern reaches [11] and there is amorphous silica, clay, epsomite and limonite. [14] [13] Other rare salt types form efflorescences at the margins of the salar. [5] There is evidence that the salts in Salar de Gorbea are presently dissolving. [15] The Salar de Gorbea environment has been described as a potential Mars analogue. [16]
The bacterial population of the salar has been investigated to determine their taxonomy, [17] research has yielded new species and genera. [18] The ponds often contain microbial mats. [10] There are also diatoms and green algae, which sometimes get encased in the gypsum crystals. [12] Its flora is poorly studied and probably consists entirely of halophyte plants at its margins. [2] There are not many animals in the region, [12] and none have been reported from the salar waters. [19]
The salt flat is nourished by a small watershed with an area of 336 square kilometres (130 sq mi). It is delimited to the east by the Cordon del Azufre, Cerro Bayo Complex and Cerro Atalaya, by Cerro los Patitos to the south and the Sierra de Gorbea to the west; other basins in the area are Salar de Pajonales, Salar de la Azufrera to the west [2] and Salar Ignorado to the south. [20] The rocks in the basin are entirely volcanic, mostly of Pleistocene age, [2] many volcanoes are eroded [21] and there is no evidence of recent activity [3] except for a steam eruption at Cerro Bayo in 2007. [1] Some of the volcanoes feature raw sulfur deposits. [3]
Salar de Gorbea has an extreme climate characterized by dry air, high aridity, strong winds, high insolation and extreme temperature fluctuations between day and night and between seasons. [12] [1] Annual precipitation only reaches 140 millimetres (5.5 in) and the annual mean temperature is about −1 °C (30 °F); [11] winter temperatures can drop to −30 °C (−22 °F). [5] During the late Pleistocene, the climate of the Altiplano was wetter [8] but there is no evidence of former shorelines although the gypsum crust was partially eroded during Holocene wet periods. [22] Strong winds blow in the area, forming large dust devils on the salar [23] that can reportedly transport gravel. [24] Snow accumulates on the mountains at Salar de Gorbea and their meltwater is a major water source for the salar. [25]
Salar de Uyuni is the world's largest salt flat, or playa, at over 10,000 square kilometres (3,900 sq mi) in area. It is in the Daniel Campos Province in Potosí in southwest Bolivia, near the crest of the Andes at an elevation of 3,656 m (11,995 ft) above sea level.
Laguna Verde is a salt lake in an endorheic basin, in the southwestern Altiplano in Bolivia. It is located in the Sur Lípez Province of the Potosí Department. It is close to the Chilean border, at the foot of the volcano Licancabur.
Cerro Bayo is a complex volcano on the northern part border between Argentina and Chile. It consists of four overlapping stratovolcanoes along a north–south line. The main volcano face is located on the Argentine side, thought the summit of the complex is just west of the border, in Chile. The volcano is about 800,000 years old, but it is associated with ongoing ground uplift encompassing also the more northerly Lastarria and Cordón del Azufre volcanoes. The 5,401-metre (17,720 ft) high summit is the source of two viscous dacitic lava flows with prominent levees that traveled to the north.
Bristol Lake is a dry lake in the Mojave Desert of San Bernardino County, California, 42 km (26 mi) northeast of Twentynine Palms.
Lascar is a stratovolcano in Chile within the Central Volcanic Zone of the Andes, a volcanic arc that spans Peru, Bolivia, Argentina and Chile. It is the most active volcano in the region, with records of eruptions going back to 1848. It is composed of two separate cones with several summit craters. The westernmost crater of the eastern cone is presently active. Volcanic activity is characterized by constant release of volcanic gas and occasional vulcanian eruptions.
Cerro Galán is a caldera in the Catamarca Province of Argentina. It is one of the largest exposed calderas in the world and forms part of the Central Volcanic Zone of the Andes, one of the three volcanic belts found in South America. One of several major caldera systems in the Central Volcanic Zone, the mountain is grouped into the Altiplano–Puna volcanic complex.
The Purico complex is a Pleistocene volcanic complex in Chile close to Bolivia, formed by an ignimbrite, several lava domes and stratovolcanoes and one maar. It is in the Chilean segment of the Central Volcanic Zone, one of the four volcanic belts which make up the Andean Volcanic Belt. The Central Volcanic Zone spans Peru, Bolivia, Chile and Argentina and includes 44 active volcanoes as well as the Altiplano–Puna volcanic complex, a system of large calderas and ignimbrites of which Purico is a member. Licancabur to the north, La Pacana southeast and Guayaques to the east are separate volcanic systems.
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Aguas Calientes Volcano or Cerro Aguas Calientes, also called Simba, is a cone-shaped stratovolcano located 5 kilometres (3 mi) east of the Lascar volcano and 10 kilometres (6.2 mi) north of Laguna Lejía, Chile. It is located within a 500 square kilometres (190 sq mi) area where the Cordón de Puntas Negras and the Cordón Chalviri volcanic chains intersect. The volcano is constructed from andesite and dacite containing hornblende and also anhydrite and its pyroclastics are all older than Lascar. It has a diameter of about 7 kilometres (4.3 mi). Some xenoliths of calc-alkaline material are found in Aguas Calientes lavas, and magma mixing has generated lavas containing andesite inclusions in dacites. One eruption of Aguas Calientes postdates the first centre of Lascar and was originally linked to the Lascar Piedras Grandes eruption, before sampling on the deposits of this eruption indicated a relationship with the Lascar volcano itself. Effusion of lava ceased after the cone was built. One summit lava flow may be of Holocene age, but no evidence of historical activity is found.
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Salar de Pajonales is a playa in the southern Atacama Region of Chile and the third-largest in that country, behind Salar de Punta Negra and Salar de Atacama. It consists mostly of a gypsum crust; only a small portion of its area is covered with water. During the late Pleistocene, Salar de Pajonales formed an actual lake that has left shoreline features.
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