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Cheuquemó Formation

Coordinates: 40°00′S 73°00′W / 40.0°S 73.0°W / -40.0; -73.0
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Cheuquemó Formation
Stratigraphic range: Late OligoceneEarly Miocene
Unit ofOsorno–Llanquihue Basin
UnderliesSanto Domingo Formation
OverliesBahía Mansa Metamorphic Complex
Thicknessmore than 1,200 m (3,900 ft)
Lithology
PrimaryConglomerate, sandstone, mudstone, tuff
OtherCoal
Location
Coordinates40°00′S 73°00′W / 40.0°S 73.0°W / -40.0; -73.0
RegionLos Lagos Region
Country Chile
Type section
Named byFloreal García
Year defined1968
Cheuquemó Formation is located in Chile
Cheuquemó Formation
Cheuquemó Formation (Chile)

Cheuquemó Formation (Spanish: Formación Cheuquemó) is a geological formation of sedimentary rock in south-central Chile. The sediments of the formation were deposited during the Late Oligocene and Early Miocene epochs. The formations lower sections are made up of conglomerate, then successions of sandstone, tuff and mudstone rich in organic material follows. The formation indicates that sedimentation occurred in an estuarine (paralic) and other non-marine (continental) environments. It contains fossils of the following genera: Mytilus, Cardium and Turritella. Stratigraphically it overlies the Bahía Mansa Metamorphic Complex and underlies the Miocene Santo Domingo Formation.[1]

Description

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The formation is very similar to the Pupunahue Beds found further north, with the sole difference that the fossil assemblage in both seem to indicate different ages. While Cheuquemó is possibly about 14 million years old (Miocene), the Pupunahue Beds are 35–25 million years old.[2]

See also

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References

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  1. ^ Elgueta, Sara; Le Roux, Jacobus; Duhart, Paul; McDonough, Michael; Urqueta, Esteban (2000). Estratigrafía y sedimentología de la cuencas terciarias de la Región de Los Lagos (39-41°30'S) (in Spanish). Santiago, Chile: Servicio Nacional de Geología y Minería. pp. 15–16. ISSN 0020-3939.
  2. ^ Alfaro, G.; Gantz, E.; Magna, O. (1990). "El yacimiento de carbón Catamutún (La Unión)". Actas. Segundo Simposio sobre el Terciario de Chile (in Spanish). Santiago, Chile: Departamento de Geociencias, Facultad de Ciencias, Universidad de Concepción. pp. 11–28.