The Magallanes Basin or Austral Basin is a major

sedimentary basin Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock. They form when long-term subside ...

in southern

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and gl ...

. The basin covers a surface of about and has a NNW-SSE oriented shape. The basin is bounded to the west by the

Andes mountains The Andes, Andes Mountains or Andean Mountains (; ) are the List of mountain ranges#Mountain ranges by length, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range i ...

and is separated from the Malvinas Basin to the east by the Río Chico-Dungeness High. The basin evolved from being an

extensional In any of several fields of study that treat the use of signs — for example, in linguistics Linguistics is the science, scientific study of human language. It is called a scientific study because it entails a comprehensive, systematic, obj ...

back-arc basin in the

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

to being a compressional

foreland basin A foreland basin is a structural basin that develops adjacent and parallel to a mountain belt. Foreland basins form because the immense mass created by crustal thickening associated with the evolution of a mountain belt causes the lithospher ...

in the

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

. Rocks within the basin are

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

in age and include the Cerro Toro Formation. Three ages of the SALMA classification are defined in the basin; the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 Ma to 15.97 ± 0.05 Ma (million years ago). It was prece ...

Santacrucian from the

Santa Cruz Formation The Santa Cruz Formation is a geological formation in the Magallanes/Austral Basin in southern Patagonia in Argentina and in adjacent areas of Chile. It dates to the late Early Miocene epoch, and is contemporaneous with eponymous Santacrucian ...

and

Friasian The Friasian age is a period of geologic time (16.3–15.5 Ma) within the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification of South America. It follows the Santacrucian and precedes the Colloncuran age. ...

from the

Río Frías Formation Río Frías Formation ( es, Formación Río Frías) is a Middle Miocene geologic formation made up sedimentary rock located in Aysén Region, western Patagonia. The formation crops out along the upper couse of Cisnes River ( es, Río Cisnes).Mar ...

and the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

Ensenadan The Ensenadan age is a period of geologic time (1.2–0.8 Ma) within the Early Pleistocene epoch of the Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the ...

from the La Ensenada Formation. The Magallanes Basin contains most of Chile's coal reserves dwarfing those found in the

Arauco Basin The Arauco Basin ( es, Cuenca de Arauco) is a sediment-filled depression –a sedimentary basin– in south-central Chile. In the context of plate tectonics it is classified as a forearc basin. The basin has an approximate area of and at its deep ...

or around

Valdivia Valdivia (; Mapuche: Ainil) is a city and commune in southern Chile, administered by the Municipality of Valdivia. The city is named after its founder Pedro de Valdivia and is located at the confluence of the Calle-Calle, Valdivia, and Cau-Cau R ...

(e.g.

Catamutún Catamutún is a coal mine and locality in Los Ríos Region, Chile.Mulpún). Its coals are lignitic to

sub-bituminous Sub-bituminous coal is a lower grade of coal that contains 35–45% carbon. The properties of this type are between those of lignite, the lowest grade of coal, and those of bituminous coal, the second-highest grade of coal. Sub-bituminous coal i ...

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: *

(

) * Río Baguales Formation ( Deseadan) * Late Cretaceous volcanic rock * Divisadero Group (

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 M ...

) * Coihaique Group (

Late Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

) ** Apeleg Formation ** Katterfeld Formation **

Toqui Formation The Toqui Formation is a geological formation in the Aysén Region of southern Chile. It has been dated to the Tithonian stage of the Late Jurassic by uranium–lead dating of zircons, providing an age of 147 ± 0.1 Ma. It consists of an sequence ...

(

Tithonian In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...

) * Ibáñez Formation

Northwestern basin

In the Argentinian parts of the basin, the following formations have been registered from north to south:Pérez Panera, 2010, p.52 *

( Santacrucian) * Cerro Boleadoras Formation (Santacrucian) * Río Jeinemeni Formation (Colhuehuapian) *

Monte León Formation Monte may refer to: Places Argentina * Argentine Monte, an ecoregion * Monte Desert * Monte Partido, a ''partido'' in Buenos Aires Province Italy * Monte Bregagno * Monte Cassino * Montecorvino (disambiguation) * Montefalcione Portugal * M ...

( Deseadan to

Colhuehuapian The Colhuehuapian age is a period of geologic time (21.0–17.5 Ma) within the Early Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Deseadan and precedes the Santacrucian a ...

) * San Julián Formation (

Late Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "daw ...

) * Campo Bola Formation * Asunción Formation *

Cardiel Formation The Cardiel Formation is a Maastrichtian geologic Formation (geology), formation of the Magallanes Basin, Austral Basin in Santa Cruz Province, Argentina, Santa Cruz Province, Argentina. The formation comprises sandstones and conglomerate (geology ...

(

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...

) *

Mata Amarilla Formation The Mata Amarilla Formation is a fossiliferous formation of the Austral Basin in southern Patagonia, Argentina. The formation consists of sediments deposited during the Middle Cenomanian, dated to 96.94 to 95.52 Ma. The middle section of the fo ...

(Albian to

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. ...

) *

Piedra Clavada Formation Piedra is a hair disease caused by a fungus, which causes formation of nodules on the hair shaft.Veasey JV, Avila RB, Miguel BAF, Muramatu LH. White piedra, black piedra, tinea versicolor, and tinea nigra: contribution to the diagnosis of superfic ...

(

) * Kachaike Formation (

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

) * Río Tarde Formation * Apeleg Formation * Cerro Toro Formation (

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded b ...

) * Divisadero Group (Aptian to Albian) * Río Belgrano Formation (

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is precede ...

to Aptian) * Springhill Formation (

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceou ...

Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.9 ± 2 Ma and 129.4 ± 1.5 Ma (million years ago). The Hauterivian is preceded by the ...

) * El Tranquilo Group (

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...

) ** Laguna Colorada Formation (

Norian The Norian is a division of the Triassic Period. It has the rank of an age (geochronology) or stage (chronostratigraphy). It lasted from ~227 to million years ago. It was preceded by the Carnian and succeeded by the Rhaetian. Stratigraphic defi ...

)

South-central basin

* La Ensenada Formation (

) * Cordillera Chica Formation * Pinturas Formation (Santacrucian) *

( Santacrucian) *

Centinela Formation Centinela may refer to: * El Centinela (Baja California), a mountain west of Mexicali, Baja California, Mexico * La Centinela, an archaeological site in the Chincha Valley of Peru * Centinela Avenue, major street in the Westside region of Los Ang ...

(

Middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn ...

) * Río Leona Formation * Río Guillero Formation * Man Aike Formation (

) * Río Turbio Formation ( Early to Late Eocene) * Calafate Formation * Cerro Dorotea Formation *

Chorrillo Formation The Chorrillo Formation, also named as Chorillo Formation,Río Leona
at Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...

) * La Irene Formation (Maastrichtian) * Monte Chico Formation (Maastrichtian) *

Cerro Fortaleza Formation The Cerro Fortaleza Formation, in older literature described as Pari Aike Formation, is a Late Cretaceous geologic formation of Campanian to Maastrichtian age (although it has formerly been reported to be Cenomanian to Santonian)Varela et al., 20 ...

(

) * Anita Formation * Cerro Cazador Formation (

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian s ...

to Maastrichtian) * Alta Vista Formation (Early to Middle Campanian) * Lago Sofía Formation * Cerro Toro Formation (

) * Río Mayer Formation ( early Hauterivian to early Albian) * Zapata Formation (

Berriasian In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago ...

) * Springhill Formation (

) *

Tobífera Formation Tobífera Formation ( es, Formación Tobífera) is a volcano-sedimentary formation of Middle to Late Jurassic age. The formation is crops out in the Magallanes Region in southern Patagonia and Tierra del Fuego of Chile, the Santa Cruz Province ...

(Late Jurassic)

Tierra del Fuego

* Irigoyen Formation * Punta Basílica Formation * Castillo Formation *

Loreto Formation Loreto Formation ( es, Formación Loreto) is a sedimentary formation of Late Eocene age in the southernmost Magallanes Basin. It overlies the Leña Dura Formation and the contact with an overlying formation is not observed.Torres et al., 2009, p. ...

( Priabonian -

Divisaderan The Divisaderan age is a South American land mammal age, covering a period of geologic time (42.0–36.0 Mya (unit), Ma) within the Middle Eocene, Middle and Late Eocene epochs of the Paleogene. It follows the Mustersan age and is followed by the Ti ...

Tinguirirican The Tinguirirican ( es, Tinguiririquense) age is a period of geologic time (36.0–29.0 Ma) within the Late Eocene and Early Oligocene epochs of the Paleogene, used more specifically within the SALMA classification in South America. It follows the ...

) * Cabo Peña Formation * Tchat Chii Formation * Cerro Colorado Formation * Leticia Formation (

Bartonian The Bartonian is, in the ICS's geologic time scale, a stage or age in the middle Eocene Epoch or Series. The Bartonian Age spans the time between . It is preceded by the Lutetian and is followed by the Priabonian Age. Stratigraphic defini ...

) * Punta Torcida Formation * Arroyo Candelaria Formation * Río Claro Formation * Policarpo Formation * Bahía Thetis Formation * Cabeza de León Formation * Arroyo Alfa Formation * Yahgan Formation * Beauvoir Formation (

) * Nueva Argentina Formation * Lemaire Formation * Pampa Rincón Formation (

) *

Chon Aike Formation The Chon Aike Formation is an extensive geological formation, present in the Deseado Massif in north-central Santa Cruz Province, Patagonia, Argentina. It covers an area of approximately and consists of rhyolitic volcanic rocks, particularly ig ...

(

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

Stratigraphy

Aysén Basin

Northwestern basin

South-central basin

Tierra del Fuego

See also

Notes

References

Bibliography

Further reading