Английская Википедия:Gracias Formation

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Шаблон:Infobox rockunit

The Gracias Formation is a geologic formation in Honduras. The mainly sandstones, siltstones and claystones preserve vertebrate fossils dating back to the Neogene period.[1]

Description

The Gracias Formation is a sedimentary unit, consisting of sandstone, siltstone, claystone and a few conglomeratic beds. The formation crops out in western Honduras and ranges from Шаблон:Convert in thickness. The formation overlies the Padre Miguel Group, while it is overlain by Pleistocene basalts.[2] The Padre Miguel Group provided the provenance for the sedimentary material for the Gracias Formation. The clasts in the formation are largely composed of rhyolite, rhyodacite, pumice, vitric ash, quartz, feldspar, and minor biotite fragments.[3]

Fossil content

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See also

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References

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Bibliography

Further reading

  • E. C. Olson and P. O. McGrew. 1941. Mammalian fauna from the Pliocene of Honduras. Bulletin of the Geological Society of America 52:1219-1244
  • S. D. Webb and S. C. Perrigo. 1984. Late Cenozoic Vertebrates from Honduras and El Salvador. Journal of Vertebrate Paleontology 4(2):237-254

  1. Gracias Formation at Fossilworks.org
  2. N.N., s.a., Informe de Apoyo, A-9
  3. Sánchez Barreda, 1999, p.25
  4. Hulbert, 1988, p.272