Guichón Formation

The Guichón Formation is a Late Cretaceous geologic formation of the Paysandú Group in Uruguay. Dinosaur remains are among the fossils that have been recovered from the formation.[1]

Guichón Formation Stratigraphic range: Late Cretaceous
Type	Geological formation
Unit of	Paysandú Group
Lithology
Primary	Sandstone
Other	Conglomerate
Location
Coordinates	32.0°S 57.7°W / -32.0; -57.7
Approximate paleocoordinates	38.4°S 30.0°W / -38.4; -30.0
Region	Paysandú Department
Country	Uruguay
Extent	Norte Basin
Type section
Named for	Guichón
Guichón Formation (Uruguay)

Description

The Guichón Formation comprises mainly pink-greyish to reddish sandstones, which contain moderate to well-sorted, subrounded, fine to medium-sized grains in a pelitic matrix. These sandstones (which compositionally are feldspathic wackes) are either massive or may instead exhibit parallel lamination, cross-lamination and graded bedding. These lithologies were deposited in southwest-trending alluvial–fluvial systems comprising low-sinuosity channels traversing through sandy plains. Subordinate to the already mentioned sandstones are conglomeratic and pelitic lithologies, interpreted as channel-fill and overbank deposits, respectively. It is inferred that the Guichón Formation was deposited in warm, semi-arid climatic conditions.[2] The formation has been correlated to the Puerto Yeruá Formation of northwestern Argentina.[3]

Fossil content

The following fossils have been reported from the formation:[2][4]

• Uruguaysuchus aznarezi
• Sphaerovum sp.
• Iguanodontia indet.
• Saltasauridae indet.
• Theropoda indet.

See also

• List of dinosaur-bearing rock formations
  • List of stratigraphic units with indeterminate dinosaur fossils
• List of fossiliferous stratigraphic units in Uruguay

References

1. Weishampel et al., 2004, pp.517-607
2. Guichón at Fossilworks.org
3. Soto et al., 2009, p.13
4. Soto et al., 2009, p.19

Bibliography

• Soto, M.; D. Perea; G. Veroslavsky; A. Rinderknecht; M. Ubilla, and G. Lecuona. 2009. Nuevos hallazgos de restos de dinosaurios y consideraciones sobre la edad de la Formación Guichón - New findings of dinosaur remains and considerations on the age of the Guichón Formation. Revista Sociedad Uruguaya de Geología 15. 11–23. Accessed 2018-09-07.
• Weishampel, David B.; Peter Dodson, and Halszka Osmólska (eds.). 2004. The Dinosauria, 2nd edition, 1–880. Berkeley: University of California Press. Accessed 2019-02-21.ISBN 0-520-24209-2

Further reading

• M. Soto, D. Perea, and A. Cambiaso. 2012. First sauropod (Dinosauria: Saurischia) remains from the Guichón Formation, Late Cretaceous of Uruguay. Journal of South American Earth Sciences 33:68-79
• F. von Huene. 1934. Neue Saurier-Zähne aus der Kreide von Uruguay [New saurian teeth from the Cretaceous of Uruguay]. Centralblatt für Mineralogie, Geologie und Paläontologie, Abteilung B: Geologie und Paläontologie 1934(4):183-189