The Huitrera Formation is a geological formation in the Neuquén Basin in northern Patagonian Argentina whose strata date back to the Early Eocene of the Paleogene, or Casamayoran in the South American land mammal age classification.

The formation is together with the Reyhuau basalts part of the Pilcaniyeu Belt, a volcanic belt active in Paleocene to middle Eocene times.

Description

The Huitrera Formation was first defined by Ravazzoli and Sesana in 1977. The name has been used to identify various volcaniclastic sequences, among others in the Ñirihuau fold-and-thrust belt. The up to 1,300 metres (4,300 ft) thick formation comprises mudstones and sandstones deposited in a crater lake environment. Part of the formation comprises andesites, dacitic and rhyolitic ignimbrites, volcanic breccias, tuffs and trachybasalts.

The formation was initially described as Late Eocene to Early Oligocene, but was later dated to 54.24 ± 0.45 Ma, meaning the Huitrera Formation is Ypresian, or in the SALMA classification, Casamayoran in age.

Fossil content

The following macrofossils were reported from the formation:

The formation has also provided many pollen, analyzed in 2003 by Melendi et al.

See also

Bibliography

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  • Ramírez, Leonardo C.; Corsolini, Juan; Di Iorio, Osvaldo (2016), "First fossil record of parasitic flat-bark beetle (Coleoptera: Passandridae) from the Eocene of Patagonia, Argentina", Ameghiniana, 53 (2): 160–169, doi:, hdl:
  • Prez, Horacio; Massaferro, Gabriela (2013), (PDF), Contribuciones Científicas GÆA, 26: 221–234
  • Barreda, V.D.; Palazzesi, L.; Katinas, L.; Criscri, J.V.; Telleria, M.C.; Bremer, K.; Passala, M.G.; Bechis, F.; Corsolini, R. (2012), "An extinct Eocene taxon of the daisy family (Asteraceae): evolutionary, ecological and biogeographical implications", Annals of Botany, 109 (1): 127–134, doi:, PMC , PMID
  • Escosteguy, Leonardo; Franchi, Mario (2010), (PDF), Revista de la Asociación Geológica Argentina, 66: 418–429
  • Báez, Ana M.; Pugener, L. Analia (2003), "Ontogeny of a new Palaeogene pipid frog from southern South America and xenopodinomorph evolution", Zoological Journal of the Linnean Society, 139 (3): 439–476, doi:
  • Melendi, D.L.; Scafati, L.H.; Volkheimer, W. (2003), "Palynostratigraphy of the Paleogene Huitrera Formation in N-W Patagonia, Argentina", Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 228 (2): 205–273, doi: