Magallanes Basin

The Magallanes Basin (predominantly used in Chile) or Austral Basin (mainly used in Argentina) is a major sedimentary basin in southern Patagonia. The basin covers a surface of about 170,000 to 200,000 square kilometres (66,000 to 77,000 sq mi) and has a NNW-SSE oriented shape.[1][2] The basin is bounded to the west by the Andes mountains and is separated from the Malvinas Basin to the east by the Río Chico-Dungeness High.[1] The basin evolved from being an extensional back-arc basin in the Mesozoic to being a compressional foreland basin in the Cenozoic.[3] Rocks within the basin are Jurassic in age and include the Cerro Toro Formation.[4] Three ages of the SALMA classification are defined in the basin; the Early Miocene Santacrucian from the Santa Cruz Formation and Friasian from the Río Frías Formation and the Pleistocene Ensenadan from the La Ensenada Formation.

Magallanes or Austral Basin
Cuenca de Magallanes, Cuenca Austral
The main geologic structures comprising the region of Patagonia, including the two basement massifs of Somún Cura and Deseado. Locations of structures based on Pankhurst et al. (2006) & Ramos (2008)
Coordinates53°00′S 69°30′W
EtymologyStrait of Magellan
Austral = "south"
LocationSouthern South America
RegionPatagonia
Country Argentina
 Chile
State(s)Santa Cruz Province
Aysén & Magallanes Regions
CitiesPunta Arenas
Ushuaia
Characteristics
On/OffshoreBoth
BoundariesAndes, Río Chico-Dungeness High
Part ofAndean foreland basins
Area170,000–200,000 km2 (66,000–77,000 sq mi)
Hydrology
Sea(s)Southern Atlantic Ocean
River(s)Shehuén River
Lake(s)Viedma, Cardiel, Argentino, Pueyrredón, Fontana
Geology
Basin typeForeland basin
OrogenyAndean
AgeJurassic-Holocene
StratigraphyStratigraphy
Field(s)Chilean coal

The Magallanes Basin contains most of Chile's coal reserves dwarfing those found in the Arauco Basin or around Valdivia (e.g. Catamutún, Mulpún). Its coals are lignitic to sub-bituminous.[5]

Stratigraphy

Aysén Basin

The northwesternmost reaches of the basin form a sub-basin known as Aysén Basin or Río Mayo Embayment. From top to bottom the fill the basin is:[6]

Northwestern basin

In the Argentinian parts of the basin, the following formations have been registered from north to south:[7]

South-central basin

Tierra del Fuego

See also

References
  1. Gallardo, Rocío E. (2014). "Seismic sequence stratigraphy of a foreland unit inthe [sic] Magallanes-Austral Basin, Dorado Riquelme Block, Chile: Implications for deep-marine reservoirs". Latin American Journal of Sedimentology and Basin Analysis (in Spanish). 1221 (1). Retrieved 7 December 2015.
  2. "Cuenca Austral". Secretaría de Energía (in Spanish). Government of Argentina. Retrieved 30 November 2015. De una superficie total de 170.000 Km2, unos 23.000 Km2 pertenecen al área costa afuera.
  3. Wilson, T.J. (1991). "Transition from back-arc to foreland basin development in the southernmost Andes: Stratigraphic record from the Ultima Esperanza District, Chile". Geological Society of America Bulletin. 103 (1): 98–111. Bibcode:1991GSAB..103...98W. doi:10.1130/0016-7606(1991)103<0098:tfbatf>2.3.co;2.
  4. Fosdick, Julie C. (2007). Late Miocene Exhumation of the Magallanes Basin and sub-Andean fold belt, southern Chile: New constrains from apatite U-Th/He thermochronology. Geological Society of America, Denver Annual Meeting (28–31 October 2007) Paper No. 123-15. Denver.
  5. Hackley, Paul C.; Warwick, Peter D.; Alfaro, Guillermo H.; Cuebas, Rosenelsy M. (2006). "World Coal Quality Inventory: Chile" (PDF). World Coal Quality Inventory: South America (Report). USGS. pp. 90–131. Retrieved February 23, 2017.
  6. Demant, A.; Suárez, M.; de la Cruz, R.; Bruguier, O (2010). "Early Cretaceous Surtseyan volcanoes of the Baño Nuevo Volcanic Complex (Aysén Basin, Eastern Central Patagonian Cordillera, Chile)". Geologica Acta. 8 (2): 207–219. doi:10.1344/105.000001530.
  7. Pérez Panera, 2010, p.52

Bibliography
Cretaceous
  • Pérez Panera, Juan Pablo. 2010. Sistemática y bioestratigrafía de los nanofósiles calcáreos del Cretácico del sudeste de la Cuenca Austral, Santa Cruz, Argentina (PhD thesis), 1–450. Universidad Nacional de La Plata.
Neogene

Further reading
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