The Magallanes Basin[A] or Austral Basin[B] 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 | |
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Cuenca de Magallanes, Cuenca Austral | |
Coordinates | 53°00′S 69°30′W / 53.000°S 69.500°W |
Etymology | Strait of Magellan Austral = "south" |
Location | Southern South America |
Region | Patagonia |
Country | Argentina Chile |
State(s) | Santa Cruz Province Aysén & Magallanes Regions |
Cities | Punta Arenas Ushuaia |
Characteristics | |
On/Offshore | Both |
Boundaries | Andes, Río Chico-Dungeness High |
Part of | Andean foreland basins |
Area | 170,000–200,000 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 type | Foreland basin |
Orogeny | Andean |
Age | Jurassic-Holocene |
Stratigraphy | Stratigraphy |
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]
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]
In the Argentinian parts of the basin, the following formations have been registered from north to south:[7]
De una superficie total de 170.000 Km2, unos 23.000 Km2 pertenecen al área costa afuera.