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 ~ | |
| Type | Geological formation |
| Unit of | Paysandú Group |
| Underlies | Mercedes Formation |
| Overlies | Arapey Formation |
| Thickness | Up to >100 m (330 ft) (in wells) |
| Lithology | |
| Primary | Sandstone |
| Other | Conglomerate |
| Location | |
| Coordinates | 32°00′S 57°42′W / 32.0°S 57.7°W |
| Approximate paleocoordinates | 38°24′S 30°00′W / 38.4°S 30.0°W |
| Region | Paysandú Department |
| Country |  Uruguay |
| Extent | Norte Basin |
| Type section | |
| Named for | Guichón |
  Guichón Formation (Uruguay) | |
Description
editThe 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
editThe following fossils have been reported from the formation:[2][6]
- Fossil eggs
See also
editReferences
edit- ^ Weishampel et al., 2004, pp.517-607
- ^ a b Guichón at Fossilworks.org
- ^ Soto et al., 2009, p.13
- ^ Tofalo et al., 2011, p.616
- ^ Tofalo et al., 2011, p.617
- ^ Soto et al., 2009, p.19
- ^ Soto, M.; Carballido, J. L.; Langer, M. C.; Silva Junior, J. C. G.; Montenegro, F.; Perea, D. (2024). "Phylogenetic relationships of a new titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Uruguay". Cretaceous Research. 160. 105894. doi:10.1016/j.cretres.2024.105894.
- ^ Mones, 1972
- ^ a b Soto et al., 2011
- ^ Soto et al., 2012
Bibliography
edit- Soto, M.; Perea, D.; Cambiaso, A. (2012), "First sauropod (Dinosauria: Saurischia) remains from the Guichón Formation, Late Cretaceous of Uruguay", Journal of South American Earth Sciences, 33: 68–79, doi:10.1016/j.jsames.2011.08.003
- Soto, M.; Perea, D. (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, doi:10.1111/j.1096-3642.2011.00717.x, hdl:11336/69086
- Tófalo, Ofelia; Pazos, Pablo J.; Sánchez Bettucci, Leda (2011), "Estudio composicional de sedimentitas silicoclásticas y paleosuelos de la Formación Mercedes (Cretácico Superior), Uruguay", Revista de la Asociación Geológica Argentina, 68: 615–626, retrieved 2020-08-23
- Soto, M.; Perea, D.; Veroslavsky, G.; Rinderknecht, A.; Ubilla, M.; Lecuona, G. (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" (PDF), Revista Sociedad Uruguaya de Geología, 15: 11–23, retrieved 2018-09-07
- Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (2004), The Dinosauria, 2nd edition, Berkeley: University of California Press, pp. 1–880, ISBN 0-520-24209-2, retrieved 2019-02-21
- 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, 1934: 183–189