Cordobés Formation

The Cordobés Formation is an Early Devonian (Pragian to Emsian) geologic formation of the Durazno Group in the Paraná Basin in the Durazno Department of central Uruguay. The shallow marine shales preserve trilobite, bivalve, gastropod and brachiopod fossils.^[1][2]

Cordobés Formation
Stratigraphic range: Pragian-Emsian ~409–392 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Durazno Group
Underlies	La Paloma Formation
Overlies	Cerrezuelo Formation
Thickness	92 m (302 ft)
Lithology
Primary	Shale
Other	Fine sandstone
Location
Coordinates	33.0°S 55.0°W / -33.0; -55.0
Approximate paleocoordinates	68.5°S 136.2°W / -68.5; -136.2
Region	Durazno Department
Country	Uruguay
Extent	Norte Basin
Type section
Named for	Arroyo Cordobés
Named by	Bossi
Year defined	1966
Cordobés Formation (Uruguay)

Description

The Cordobés Formation is characterized by reddish fine shale deposited in a shallow marine environment.

Fossil content

The following fossils have been reported from the formation:^[1][3]

• Trilobites
  • Acaste sp.
  • Burmeisteria sp.
  • Metacryphaeus sp.
  • ?Calmonia sp.
  • ?Paracalmonia sp.
  • ?Pennaia sp.
• Lophophorata
  • Tentaculites sp.
• Strophomenata
  • Australostrophia sp.
  • Notiochonetes sp.
  • Schuchertella sp.
• Rhynchonellata
  • Derbyina sp.
  • Australospirifer sp.
  • Australocoelia sp.
• Lingulata
  • Orbiculoidea sp.
  • "Lingula" sp.
  • Styliolina sp.
  • "Serpulites" sp.
• Bivalves
  • Modiolus sp.
  • Modiomorpha sp.
  • Goniophora sp.
  • Pleurodapis sp.
  • Nuculites sp.
  • "Nuculana" sp.
• Gastropods
  • Encrinaster sp.
  • Plectonotus sp.

See also

• List of fossiliferous stratigraphic units in Uruguay

References

1. Emsian Loc. 1 of Melo: Uraguayan outcrop belt at Fossilworks.org
2. Daners et al., 2017
3. Melo, 1988

Bibliography

• Daners, Gloria; Le Hérissé, Alain; Breuer, Pierre; Veroslavsky, Gerardo (2017), "Pragian–Emsian palynomorphs from the Cordobés Formation, Norte Basin, Uruguay: stratigraphically restricted and regionally correlative palynological events in the cool-water Malvinokaffric Realm", Palynology, 41 (sup1): 121–137, doi:10.1080/01916122.2017.1366115, ISSN 0191-6122
• Melo, J. H. G (1988), The Malvinokaffric realm in the Devonian of Brazil. N. J. McMillan, A. F. Embry, and D. J. Glass, eds. Devonian of the World, Volume I, Canadian Society of Petroleum Geologists. Calgary, Alberta, Canada, pp. 669–703