Candeleros Formation

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The Candeleros Formation is a geologic formation that outcrops in Río Negro, Neuquén, and Mendoza provinces of Argentina. It is the oldest formation in the Neuquén Group and belongs to the Río Limay Subgroup.

The type locality of the Candeleros Formation is Candeleros Hill in Neuquén province (Wichmann, 1929). This formation unconformably overlies the Lohan Cura Formation, and it is in turn overlain by the Huincul Formation, also a unit of the Neuquén Group.

Contents 1 Age 2 Composition 3 Paleontology 4 References

[edit] Age

Era: Mesozoic
Period: Late Cretaceous
Faunal stage: early Cenomanian
Absolute Age: ~100 to ~97 mya

[edit] Composition

The Candeleros Formation is almost 300 meters thick in some sections. Overall, the formation represents an ancient braided river system, made up mostly of sandstones and conglomerates. There are also isolated sections that represent eolian (wind-blown) deposition, as well as siltstones deposited under swamp conditions. Paleosols (soil deposits) are common in some sections as well.

[edit] Paleontology

One of the most productive fossil localities in the Candeleros is known as 'La Buitrera' and is now well-known for producing many small tetrapod skeletons with three-dimensional preservation, although larger fossils, such as dinosaurs, are rare. Much larger dinosaur fossils have been recovered from other sites in the formation, however, including one of the largest carnivores known, Giganotosaurus. The Candeleros has a very diverse fossil fauna, including:

• fish
• frogs
• sphenodontians
• primitive snakes (including Najash)
• several turtles (including 2 species of Prochelidella)
• abundant crocodilians (including a species of Araripesuchus)
• rebbachisaurid sauropods (including Limaysaurus)
• titanosaurian sauropods {including Andesaurus)
• a carcharodontosaurid theropod (Giganotosaurus)
• a dromaeosaurid theropod (Buitreraptor)
• cladotherian mammals

There are also several trackway sites known from the Candeleros, including theropods, sauropods, ornithopods, and pterosaurs.

[edit] References

• Leanza, H.A,, Apesteguia, S., Novas, F.E. & de la Fuente, M.S. 2004. Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages. Cretaceous Research. 25(1): 61-87.
• Wichmann, R. 1929. Los Estratos con Dinosaurios y su techo en el este del Territorio del Neuquén. Dirección General de Geología, Minería e Hidrogeología Publicación 32: 1-9.