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.

Corda Formation
Stratigraphic range: Late Aptian-Early Albian ~115–110 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Underlies	Sardinha Formation
Overlies	Itapecuru Formation
Lithology
Primary	Red sandstone
Location
Coordinates	5.7°S 47.5°W / -5.7; -47.5
Approximate paleocoordinates	5.1°S 14.8°W / -5.1; -14.8
Region	Tocantins
Country	Brazil
Extent	Parnaíba Basin
Type section
Named for	Corda River
Corda Formation (Brazil)

Large-scale fossil sauropod tracks have been reported from the formation.^[1][2][3][4]

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.^[1]

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.^[1]

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.^[1]

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