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: Aptian-Santonian
~
TypeGeological formation
Unit ofPaysandú Group
UnderliesMercedes Formation
OverliesArapey Formation
ThicknessUp to >100 m (330 ft) (in wells)
Lithology
PrimarySandstone
OtherConglomerate
Location
Coordinates32.0°S 57.7°W / -32.0; -57.7
Approximate paleocoordinates38.4°S 30.0°W / -38.4; -30.0
RegionPaysandú Department
Country Uruguay
ExtentNorte Basin
Type section
Named forGuichón
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]

The formation reaches a thickness of more than 100 metres (330 ft) in wells perforating the formation.[4] It is overlain by the Mercedes Formation and overlies the Arapey Formation.[5]

Fossil content

The following fossils have been reported from the formation:[2][6]

Fossil eggs

See also

References
  1. Weishampel et al., 2004, pp.517-607
  2. Guichón at Fossilworks.org
  3. Soto et al., 2009, p.13
  4. Tofalo et al., 2011, p.616
  5. Tofalo et al., 2011, p.617
  6. Soto et al., 2009, p.19
  7. Mones, 1972
  8. Soto et al., 2011
  9. Soto et al., 2012

Bibliography
  • Soto, M.; 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.
  • Soto, M., and D. Perea. 2011. A new specimen of Uruguaysuchus aznarezi (Crocodyliformes: Notosuchia) from the middle Cretaceous of Uruguay and its phylogenetic relationships. Zoological Journal of the Linnean Society 163. S173–S198.
  • Tófalo, Ofelia; Pablo J. Pazos, and Leda Sánchez Bettucci. 2011. Estudio composicional de sedimentitas silicoclásticas y paleosuelos de la Formación Mercedes (Cretácico Superior), Uruguay. Revista de la Asociación Geológica Argentina 68. 615–626. Accessed 2020-08-23.
  • 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
  • Mones, A. 1972. Lista de los vertebrados fósiles del Uruguay, I. Chondrichthyes, Osteichthyes, Reptilia, Aves - List of the fossil vertebrates of Uruguay, I. Chondrichthyes, Osteichthyes, Reptilia, Aves. Comunicaciones Paleontologicas del Museo de Historia Natural de Montevideo 1. 23–35.
  • von Huene, F. 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. 183–189.
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