Corda Formation

Corda Formation
Stratigraphic range: Early Cretaceous
Type Geological formation
Lithology
Primary red sandstone
Location
Coordinates 05º46´S-47º31´W[1]
Region Parnaíba River Basin
State of Tocantins
Country Brazil

The Corda Formation is a red sandstone geologic formation in the Parnaíba River Basin, in State of Tocantins of Brazil.

It was formed during the Neoaptian to Eoalbian series of the Early Cretaceous subperiod of the Mesozoic Era.

Fossil sauropod tracks have been reported from the formation.[1][2]

Origin

The Corda Formation is characterized by deposits of 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 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

References

  1. 1 2 3 4 5 Alves, Y.M. (2010). "Report on the Upper Permian and Lower Cretaceous fossiliferous localities vertebrates-bearing in the centralnorth of Tocantins State, Brazil" (PDF). Brazilian Geographical Journal: Geosciences and Humanities research medium, Uberlândia 1 (2): 372–386.
  2. Weishampel, David B.; Dodson, Peter; Osmólska, Halszka. The Dinosauria (2nd ed.). Berkeley: University of California Press. p. 861. ISBN 0-520-24209-2.


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