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.

Origin

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.

Occurrence

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.

Lithology

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.

See also

• 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

Bibliography

• Alves, Y.M (2010), (PDF), Brazilian Geographical Journal: Geosciences and Humanities research medium, Uberlândia, 1 (2): 372–386
• Leonardi, Giuseppe (1994), , Ministerio de Minas e Energia - Companhia de Pesquisa de Recursos Minerais, Geological Service of Brazil, pp. 1–248
• Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (2004), , Berkeley: University of California Press, pp. 1–880, ISBN 0-520-24209-2{{citation}}: CS1 maint: publisher location (link)