Tralcán Formation (Spanish: Formación Tralcán) is a sedimentary formation of Triassic age in Los Ríos Region in south–central Chile. It overlies unconformably the Trafún Metamorphic Complex. Tralcán Formation and nearby Panguipulli Formation form possibly the remnants of an ancient lake and river system. The formation is named after Mount Tralcán on the western edge of Riñihue Lake.[1]

Tralcán Formation
Stratigraphic range: Rhaetian
TypeGeological formation
UnderliesQuaternary glacial deposits
OverliesTrafún Metamorphic Complex
Thickness>800 m (2,600 ft)
Lithology
PrimaryConglomerate, sandstone, mudstone
OtherShale
Location
Coordinates39°48′S 72°30′W / 39.8°S 72.5°W / -39.8; -72.5
RegionLos Ríos Region
Country Chile
Type section
Named forTralcán
Named byAguirre & Levi
Year defined1964
Tralcán Formation is located in Chile
Tralcán Formation
Tralcán Formation (Chile)

Description

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The Tralcán Formation was first defined by Aguirre and Levi in 1964, based on the outcrop at Tralcán. The more than 800 metres (2,600 ft)[1] thick formation comprises reddish-grey conglomerates with a sandy matrix and intercalated reddish shales. The shales of the formation contain abundant fossil flora. Fossils of Cladophlebistenia oeshi have helped to redefine the age of the formation, that was formerly considered Late Jurassic (Kimmeridgian to Tithonian), to the Rhaetian of the Triassic.[2]

Fossil content

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The following genera of fossil flora have been identified in the formation:[1]

References

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  1. ^ a b c Herbst et al., 2005
  2. ^ Di Biase & Lillo, 1973, p.12

Bibliography

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  • Di Biase F., Francisco; Lillo R., Fernanda (1973), Geología Regional, Geoquímica de Drenaje y Minería de la Provincia de Valdivia (PDF), Instituto de Investigación de Recursos Naturales, pp. 1–101, retrieved 2019-02-21
  • Herbst, Rafael; Troncoso, Alejandro; Muñoz, Jorge (2005), "Las tafofloras triásicas de la región de los Lagos, Xma Región, Chile", Ameghiniana (in Spanish), 42 (2), retrieved 2019-02-21