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.Weishampel et al., 2004, pp.517-607
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. The formation has been correlated to the Puerto Yeruá Formation of northwestern Argentina.Soto et al., 2009, p.13
The formation reaches a thickness of more than in wells perforating the formation.Tofalo et al., 2011, p.616 It is overlain by the Mercedes Formation and overlies the Arapey Formation.Tofalo et al., 2011, p.617
Fossil content The following fossils have been reported from the formation:Guichón at Fossilworks.orgSoto et al., 2009, p.19
Dinosaurs
Ornithischians Ornithischians of the Guichón Formation Genus Species Location Stratigraphic position Material Notes Images Iguanodontia indet.Soto et al., 2011 Indeterminate Paysandú Department, Uruguay Aptian to Santonian Teeth A iguanodontian ornithopod
Sauropods Sauropods of the Guichón Formation Genus Species Location Stratigraphic position Material Notes Images Mesetasaurus M. protector Paysandú Department, Uruguay Coniacian to Maastrichtian Caudal vertebrae A aeolosaurin lithostrotian Udelartitan U. celeste Paysandú Department, Uruguay Santonian to Campanian Partial skeleton A saltasauroid titanosaur
Theropods Theropods of the Guichón Formation Genus Species Location Stratigraphic position Material Notes Images Theropoda indet. Indeterminate Paysandú Department, Uruguay Aptian to Santonian Teeth An indeterminate theropod
Crocodylomorphs Crocodylomorphs of the Guichón Formation Genus Species Location Stratigraphic position Material Notes Images UruguaysuchusMones, 1972 U. aznarezi Paysandú Department, Uruguay Campanian to Maastrichtian A uruguaysuchid notosuchian
Oofossils Oofossils of the Guichón Formation Genus Species Location Stratigraphic position Material Notes Images SphaerovumSoto et al., 2012 S. sp Paysandú Department, Uruuay
See also List of dinosaur-bearing rock formations List of stratigraphic units with indeterminate dinosaur fossils List of fossiliferous stratigraphic units in Uruguay
References
Bibliography