The Caiuá Formation is an

Early Cretaceous The Early Cretaceous (geochronological name) or the Lower Cretaceous ( chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pr ...

geologic

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondary ...

in Brazil and Paraguay. Fossil

theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally ...

tracks have been reported from the formation.Weishampel, ''et al.'' (2004). "Dinosaur distribution." Pp. 517-607. The formation, the lowermost unit of the

Bauru Group The Bauru Group is a geological group of the Bauru Sub-basin, Paraná Basin in Minas Gerais, São Paulo, General Salgado, Itapecuru-Mirim, Mato Grosso, Brazil whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils t ...

, was deposited in the

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma ( million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is pre ...

and

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ag ...

epochs of the

, around 130 to 120 Ma. The formation is

unconformably An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

overlain by the Santo Anastácio Formation and the unconformity probably represents the start of the opening of the

South Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe an ...

and the formation of the

Santos Basin The Santos Basin ( pt, Bacia de Santos) is an approximately large mostly offshore sedimentary basin. It is located in the south Atlantic Ocean, some southeast of Santos, Brazil. The basin is one of the Brazilian basins to have resulted from th ...

.Brusatte ''et al.'', 2017, p.1469

References

Bibliography

* * {{ISBN, 0-520-24209-2 Geologic formations of Brazil Geologic formations of Paraguay Lower Cretaceous Series of South America Cretaceous Brazil Aptian Stage Barremian Stage Sandstone formations Ichnofossiliferous formations Fossiliferous stratigraphic units of South America Paleontology in Brazil Formations Formations

See also

References

Bibliography