Corda Formation

The Corda Formation is a red sandstone geologic formation in the Parnaíba Basin in Tocantins, Brazil. It was formed during the Neoaptian to Eoalbian series of the Early Cretaceous.

Large-scale fossil sauropod tracks have been reported from the formation.

The Corda Formation is characterized by reddish sandstones, that were probably deposited in windy deserts and fast flowing freshwater streams. Therefore, fossils are very rare.

This formation outcrops in the central part of the Parnaíba Basin, between the mouth of the Araguaia River in the west the Parnaíba River in the east.

The Corda Formation consists largely of red sandstone, with very fine to medium grain size, rich in zeolites and iron oxide. Where whinstones^{[clarification needed]} are overlaying fragments of this rock are also present. Typical structures of wind dunes (cross bedding, ripples, and grain flow) are common. This is consistent with deposition in a desert system.

• List of dinosaur-bearing rock formations
• Sauropod tracks
• Romualdo Formation, contemporaneous fossiliferous formation of the Araripe Basin
• Itapecuru Formation, contemporaneous fossiliferous formation of the São Luis and Parnaíba Basins

• Alves, Y.M (2010), "Report on the Upper Permian and Lower Cretaceous fossiliferous localities vertebrates-bearing in the central north of Tocantins State, Brazil" (PDF), Brazilian Geographical Journal: Geosciences and Humanities research medium, Uberlândia, 1 (2): 372–386, retrieved 2019-02-16
• Leonardi, Giuseppe (1994), Annotated Atlas of South America Tetrapod Footprints (Devonian to Holocene) with an appendix on Mexico and Central America, Ministerio de Minas e Energia - Companhia de Pesquisa de Recursos Minerais, Geological Service of Brazil, pp. 1–248, retrieved 2019-03-25
• 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{{citation}}: CS1 maint: publisher location (link)