Laguna del Negro Francisco

Coordinates: 27°28′S 69°14′W / 27.467°S 69.233°W / -27.467; -69.233
This is a good article. Click here for more information.
Source: Wikipedia, the free encyclopedia.

Laguna del Negro Francisco
closed lake in the country. It is situated 200 kilometres (120 mi) northeast of the city of Copiapó. The lake is about 10 kilometres (6.2 mi) long and 4 kilometres (2.5 mi) wide with a surface area of about 20.7 square kilometres (8.0 sq mi) and a depth of about 1 metre (3 ft 3 in). A peninsula, probably formed by a moraine
and subsequently modified by wind-driven accumulation of sand, separates the lake into a north-northwesterly and a south-southeasterly half with different colour and water composition.

The lake is of tectonic origin and lies within a basin bordered by mountain ranges to the east and the west and two volcanoes north and south. It formed when the

water rights to the Astaburuaga River
.

Geography and geomorphology

Laguna del Negro Francisco lies 200 kilometres (120 mi) northeast of the city of

National Forest Corporation building is close to the southwestern shore of the lake.[4] The area has been called a "scenic beauty".[5]

The lake lies at an elevation of 4,125 metres (13,533 ft),[1] is 10 by 4 kilometres (6.2 mi × 2.5 mi) wide[6] and has a surface area of 20.7 square kilometres (8.0 sq mi), but a depth of only about 1 metre (3 ft 3 in);[1] the Ministry of Public Works estimated a mean depth of 7 metres (23 ft) in 1941.[7] The water surface can fluctuate between 17–31 square kilometres (6.6–12.0 sq mi) from year to year.[8]

The lake is subdivided into a northern or northwestern and a southern or southeastern part by a

glaciation.[9][1] Under present-day water levels, the sandbank separates the lake into two parts with different water composition: The southern part has fresher water and thus has a different colour than the saline northern part, as wetlands formed in the southern part.[9][11]

Regional rivers; Laguna de Negro Francisco and Rio Astaburuaga are upper-right of centre

The land around the lake is formed by

alluvial deposits such as gravels, sands and silts.[1] A number of mountains surround the lake, such as the 6,080 metres (19,950 ft) high Copiapó and the 5,880 metres (19,290 ft) Jotabeche.[7]

The Astaburuaga River enters the lake on its eastern shore;[12] it originates on the mountains east of Laguna del Negro Francisco where it is nourished by snowmelt.[8] Other tributaries are the Quebrada Azufre in the northwest, Rio de la Sal in the northeast and Rio La Gallina in the southwest;[4] the tributaries of Laguna del Negro Francisco feature wetlands[6] and marsh vegetation has developed at the mouth of the Astaburuaga.[12]

Hydrology and biology

The lake is

polymictic,[1] meaning that the water in the lake is usually layered but mixes over several times in the year.[13] Aragonite, calcite, dolomite, gypsum and halite precipitate out of the water.[14] In sediments remnants of characeae, diatoms, ostracods and Ruppia have been found;[15] today only one ostracod species persists in the lake.[16] Flamingos exist in the area and the lake is an important site for birds.[17]

The watershed of Laguna del Negro Francisco covers a surface area of 930 square kilometres (360 sq mi).

alluvial cone separates the Astaburuaga River in the Valle Ancho gorge from the Salar de Maricunga/[20] Cíenaga Redonda watershed.[18]

The lake has no

closed basin in Chile;[21] however during former lake level highstands the lake overflowed at 4,236 metres (13,898 ft) into the Salar de Maricunga.[15] The lake was once thought to be the source of the Copiapó River.[6]

Geology

Geologically, the lake is located in a 200 square kilometres (77 sq mi)

normal faults border the depression which is closed to the north and the south by the Quaternary volcanoes Copiapó and Jotabeche, respectively. Oligocene to Pliocene andesites of the Negro Francisco Formation and Quaternary sediments cover the depression, the latter especially in the east.[1] The depression extends past these volcanoes to the Salar de Pedernales and the Salar de Maricunga;[22]

Climate and life

There is little information on the climate of the lake, but average temperatures are 1–2 °C (34–36 °F) and precipitation mostly falls during winter from

cold desert.[24]

Vegetation is scarce at these altitudes

vizcachas, while birds include the Andean goose, three flamingo species[26] Andean gull, Baird's sandpiper, crested duck and horned coot; in total there are about 17 bird species.[27] The area is a protected area[2] as part of the Nevado Tres Cruces National Park[8] and was declared a Ramsar site in 1996, a site of international importance to waterbirds.[28]

Lacustrine history

In the past, the Astaburuaga River did flow to the Salar de Maricunga; tectonic subsidence of the Negro Francisco Basin eventually led to a

river capture involving a former tributary of the Astaburuaga reversing into the Negro Francisco basin and finally capturing the Astaburuaga itself.[22] This event is responsible for the formation of Laguna del Negro Francisco within the basin, as without the Astaburuaga's input there would not be enough water to sustain a permanent lake.[29]

Older

Mediterranean parts of Chile it ended together with the Pleistocene for not yet clear reasons.[31] Underwater shorelines also exist, indicating that at times the lake level was lower than today.[32]

During the

peat bogs formed in valleys.[34]

After 1,800 years before present, the lake became saltier again, either because of salt accumulation or because the lake shrank; the latter possibility is more likely. More recent fluctuations have occurred as well; a dry period may be associated with the

little ice age.[34] Between 1985 and 2016, glacier coverage declined by about 32%.[35] In 2012-2015 environmental degradation in the area has become apparent, accompanied by a shrinkage of water surfaces and dropping groundwater levels.[36]

Human use

In prehistory, first

Inca were active in the valleys south and southwest from Laguna del Negro Francisco[38] and also on the Copiapó and Jotabeche.[39]

A 1921 publication mentioned a project to divert waters of the Astaburuaga River for irrigation purposes.[40] Later, projects were devised which envisaged capturing the discharge into the lake in a canal and transfer the water through a tunnel into the Figueroa River,[25] (one of the headwaters of the Copiapó River;[41]) or to divert the Astaburuaga River into the Salar de Maricunga and from there into the Copiapó River catchment.[25] In 2009, a mining company held rights to divert about 0.34 cubic metres per second (12 cu ft/s) from the Astaburuaga River.[42] The waters of the lake itself are not suited for either drinking or irrigation purposes.[25]

Notes

  1. ^ Between 1943 and 1945, an annual precipitation of 118 millimetres per year (4.6 in/year) was measured.[24]

References

  1. ^ a b c d e f g h i j Grosjean et al. 1997, p. 152.
  2. ^ a b c d Iriarte & Venegas 2000, p. 71.
  3. SERNAGEOMIN
    (in Spanish). p. 6. Retrieved 16 November 2018.
  4. ^ a b Iriarte & Venegas 2000, p. 74.
  5. ^ UNIDAD DE GESTION PATRIMONIO SILVESTRE 1997, p. 17.
  6. ^ a b c Muñoz, Santiago (1894). Jeografía descriptiva de las provincias de Atacama i Antofagasta (in Spanish). Santiago de Chile: University of California. p. 45.
  7. ^ a b Niemeyer 1980, p. 255.
  8. ^ a b c Rundel & Kleier 2014, p. 3.
  9. ^ a b c d e f Wilkinson, M. Justin (18 March 2010). "Laguna del Negro Francisco". NASA Earth Observatory. Archived from the original on 16 November 2018. Retrieved 16 November 2018.
  10. ISBN 9783319296173
    .
  11. ^ Grosjean et al. 1997, pp. 152–153.
  12. ^ a b Valero-Garcés et al. 1999, p. 105.
  13. doi:10.1139/f83-207
    .
  14. S2CID 225775365
    .
  15. ^ a b c d e Grosjean et al. 1997, p. 153.
  16. ISSN 0031-0182
    .
  17. ^ Rundel & Kleier 2014, p. 4.
  18. ^ a b c UNIDAD DE GESTION PATRIMONIO SILVESTRE 1997, p. 27.
  19. ^ Niemeyer 1980, p. 256.
  20. ^ Niemeyer 1980, p. 249.
  21. ^ Risacher, François; Alonso, Hugo; Salazar, Carlos (1999). "Geoquimica de aguas en cuencas cerradas: I, II y III regiones - Chile" (PDF) (in Spanish). p. 9. Archived (PDF) from the original on 9 March 2016. Retrieved 17 November 2018.
  22. ^ a b c d Valero-Garcés et al. 1999, p. 104.
  23. ^ Valero-Garcés et al. 1999, p. 102.
  24. ^ a b UNIDAD DE GESTION PATRIMONIO SILVESTRE 1997, p. 23.
  25. ^ a b c d Niemeyer 1980, p. 257.
  26. ^ Lagos, Nicolás; Villalobos, Rodrigo; Iriarte, Agustín (2012). "Nuevos registros de poblaciones de Chinchilla de cola corta, Chinchilla chinchilla, (Rodentia: Chinchillidae) en la cordillera de la región de Atacama, Chile". Boletín del Museo Nacional de Historia Natural, Chile (in Spanish). 61: 193. Archived from the original on 2019-03-27. Retrieved 2018-11-17.
  27. ^ "Laguna del Negro Francisco concentra la mayor cantidad de aves altoandinas avistadas en Atacama". Revista Tierra Cultah (in Spanish). 27 February 2018. Archived from the original on 3 March 2018. Retrieved 2019-08-20.
  28. ^ UNIDAD DE GESTION PATRIMONIO SILVESTRE 1997, p. 1.
  29. ^ Valero-Garcés et al. 1999, p. 123.
  30. ^ Stoertz & Ericksen 1974, p. 53.
  31. ^ Grosjean et al. 1997, p. 151.
  32. ^ Stoertz & Ericksen 1974, p. 63.
  33. ^ Grosjean et al. 1997, p. 156.
  34. ^ a b Grosjean et al. 1997, p. 158.
  35. ^ Flores, Betzabé; García, Ayón; Ulloa, Christopher (December 2018). Evolución espacial y temporal de glaciares descubiertos en la Región de Atacama, Chile (PDF). 15th Chilean Geological Congress (in Spanish). p. 743. Retrieved 13 November 2022.
  36. ISSN 0719-4633. Archived
    from the original on 18 November 2018. Retrieved 17 November 2018.
  37. ^ PERALTA, Paulina; GONZÁLEZ, Carlos; WESTFALL, Catherine; SANTANDER, Gabriela (2010). "Primeras aproximaciones sobre la arqueología de Pampa Austral: Explotación y tecnología lítica al interior de la Región de Atacama (Chile)". En Actas del XVII Congreso Nacional de Arqueología Chilena (in Spanish). 2: 304 – via Academia.edu.
  38. ^ Gaete 1999, p. 225.
  39. ^ Gaete 1999, p. 225,234.
  40. Hein Online
    .
  41. ^ Gaete 1999, p. 224.
  42. ^ "Volcán sigue aumentando reservas". Míneria Chilena (in Spanish). 9 June 2009. Retrieved 17 November 2018.

Sources

Retrieved from "https://en.wikipedia.org/w/index.php?title=Laguna_del_Negro_Francisco&oldid=1184909830"