Miscanti Lake

Laguna Miscanti lies in the Central Andes[2] of Chile,[3] east-southeast of the Salar de Atacama. Administratively, it is part of the Antofagasta Region.[4] The closest town is Socaire, 20 kilometres (12 mi) away from the lake.[5] A road departing from the Paso Sico international road goes to Miscanti,[6] which is accessible by an unpaved road and numerous footpaths.[7] In 2002, there were 5,000 tourists at Miscanti and the nearby lake Miñiques,[8] and in 2015, one in three tourists who went to the Los Flamencos National Reserve visited Miscanti and Laguna Miñiques.[9] An archeological site called "Miscanti-1" is found on the southeastern lake shore.[10]

Laguna Miscanti is a maximally 10 metres (33 ft) deep lake with[11] clear[12] brackish water which covers a surface area of 13.5 square kilometres (5.2 sq mi);[11] the lake has the shape of an arrowhead with a peninsula jutting from the northern shore.[3] A lava flow separates the otherwise flat lake floor into two basins.[13] In the Atacama Altiplano, Laguna Miscanti is among the biggest waterbodies.[14] The mountains Cerro Miscanti (5,622 metres (18,445 ft)) and Cerro Miñiques (5,910 metres (19,390 ft)) lie northeast and south of the lake, respectively.[15]

1.5 kilometres (0.93 mi) south of[16] the lake is another waterbody, Laguna Miñiques.[17] In the past, the two lakes were connected, producing a large waterbody which has left beach terraces in the landscape[11] and whose water levels were about 20 metres (66 ft) higher than today.[18] The separation of the lakes probably occurred during the Pleistocene, when a lava flow erupted from Cerro Miñiques split the lake basin in two.[19][20] A number of creeks enter into Laguna Miscanti from the north, east and south (Quebrada de Chaquisoqui[1]), and there are two springs on its northern shores.[3]

Miscanti and Miñiques occupy fault-bound basins;[16][11][21] the Quebrada Nacimiento fault[18] is also known as the Miscanti Fault and is part of a detachment fault system east of the Salar de Atacama,[22] which separates the Western Cordillera from the Cordillera Domeyko.[21][12] This fault extends from the Purico complex,[23] Llano de Chajnantor to Miñiques and has formed a ridge, which has dammed lava flows from Cerro Miscanti and Cerro Miñiques.[20] The basins developed during the Pliocene and Pleistocene;[18] Laguna Lejia also developed along this fault[21] and the fault segment there is also known as Miscanti-Callejon de Varela fault.[24] Volcanoes[21] including Lascar[25] and the Cerros Saltar and Corona north and south of Lascar formed on the fault.[26]

The catchment of the lake consists mainly of volcanic and sedimentary rocks ranging from Miocene to Holocene age and covers a surface area of 320 square kilometres (120 sq mi),[11] with Quaternary volcanoes that reach elevations of 5,000–6,000 metres (16,000–20,000 ft).[5] The Cordon de Puntas Negras is the principal source of water.[18] Water reaches Laguna Miscanti principally as groundwater,[12] which is directed there by the fault; this may explain why Laguna Miscanti is a permanent lake rather than a playa.[19]

The lake has no surface outflow. Presently, water seeps to Miñiques through a lava flow[11] along the path of the Quebrada Nacimiento fault;[18] during former lake highstands a combined lake overflowed into the Pampa Varela basin[11] south-southwest of Miñiques.[15] Most water, however, leaves Laguna Miscanti through evaporation.[21] The town of Peine draws its water supply from the Miscanti basin.[27]

Presently, the regional climate is arid,[17] with average precipitation amounting to 200–250 millimetres per year (7.9–9.8 in/year), and cold, with average annual temperatures of 2 °C (36 °F). During winter, ice develops on the lake surface.[11] The lake area is usually a little warmer than the surrounding region.[28] The region lies between areas dominated by summer precipitation in the northeast and areas dominated by winter precipitation in the southwest.[17]

In the late Pleistocene and early Holocene the climate was much wetter and lakes expanded,[17] especially during the first stage[29] of the Central Andean Pluvial Event.[30] The late Pleistocene—early Holocene wet period was particularly noticeable in the Altiplano, where two separate phases of the Lake Tauca occurred.[31] The last glacial maximum was drier[32] and colder, leading to a total disappearance of vegetation[33] and a drying of the lake between 22,000 and 14,000 years ago.[34] During the middle Holocene dry period,[17] the lake may have dried up completely, forming a bog.[12] After about 4,000 years ago, moisture availability increased again,[35] while a moist epoch between 6,500 and 5,000 years ago was temporary.[36] Climate variability influenced human settlement in the region during the Holocene, which took place mainly during wetter periods[37] and became concentrated in several environmentally favourable spaces during dry periods.[16]

Widgeonweed grows at the lakeshores,[38] while the algae charophytes[39] and Chara and the water plant Myriophyllum grow in the lake. During its highstands, algal bioherms[38] and stromatolithes developed in the water.[18] Diatoms and ostracodes have been identified in the lake sediments,[40] and amphipods in the lake waters.[41]

There are meadows consisting of Fabiana, Festuca and Stipa chrysophylla around the lake, with sparser vegetation found on the upland,[12] consisting of Baccharis species also known as "tolar" and ichu.[42] Fauna that inhabits the area includes birds like flamingos,[43] Fulica ardesiaca (Andean coot), Fulica cornuta (Horned coot), Larus serranus (Andean gull), Lophonetta speculiarioides (Crested duck) and Podiceps occipitalis (silvery grebe),[44] and mammals like Ctenomys opimus (Highland tuco-tuco), Lagidium viscacia (Southern viscacha), Phyllotis darwini (Darwin's leaf-eared mouse), Pseudalopex culpaeus (culpeo) and Vicugna vicugna (vicuña);[43] the two lakes are important breeding sites for the horned coot.[45] Laguna Miscanti and Laguna Miñiques are part of the third sector of the Los Flamencos National Reserve,[46] and are jointly administered by the community of Socaire and by the National Forest Corporation.[47]