The Cerro Carnerero Formation is a geological formation of the Golfo San Jorge Basin in Chubut Province, Patagonia, Argentina.Cañadón Puelman
at

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Description

The

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too sm ...

s and tuffs of the approximately thick formation,Cortés, 1986, p.50 belonging to the

Lonco Trapial Group A lonko or lonco (from Mapudungun ''longko'', literally "head"), is a chief of several Mapuche communities. These were often ulmen, the wealthier men in the lof. In wartime, lonkos of the various local rehue or the larger aillarehue would gather i ...

,Cortés, 1986, p.49 were deposited in a

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

environment.Cortés, 1986, p.53 The formation dates back to the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

( Toarcian stage) and has preserved fossils of '' Cladophlebis oblonga'',Cortés, 1986, p.52 and '' Amygdalodon patagonicus''.Weishampel et al., 2004, p.542 The fossiliferous beds rest on Liassic beds with ''

Harpoceras subplanatum ''Harpoceras'' is an extinct genus of ammonite belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during the Toarcian age from the Falciferum zone to the Commune subzone of the Bifrons zone.Sepkoski, JacSepk ...

'', and below the Middle to Upper Jurassic

Porphyritic Series Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning a ...

. Called the "Cerro Carnerero" beds, Rauhut, 2008, assigned the Cerro Carnerero to the Toarcian to Bajocian.

Lithology

The formation comprises sandy tuffs and bluish gray claystones, which form part of a continental sedimentary series mixed with porphyritic conglomerates with partly encrusted round pebbles, and bluish gray clays with sandy intercalations and clays in lesser amounts.

Description

Lithology

Fossil content

Vertebrate fauna

Arthropods

See also

References

Bibliography

Further reading