Huayquerías Formation
Stratigraphic range: Messinian-Zanclean (defined as Huayquerian) ~6.5–5 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Underlies	Tunuyán Formation
Thickness	Up to 126 m (413 ft)
Lithology
Primary	Mudstone
Other	Sandstone, tuff
Location
Coordinates	33°48′S 69°00′W / 33.8°S 69.0°W / -33.8; -69.0
Approximate paleocoordinates	34°00′N 66°54′W / 34.0°N 66.9°W / 34.0; -66.9
Region	Mendoza Province
Country	Argentina
Extent	Frontal Cordillera & Cuyo Basin
Type section
Named by	Kraglievitch
Year defined	1934
Region	Mendoza Province
Country	Argentina
Huayquerías Formation (Argentina)

The Huayquerías Formation (Spanish: Formación Huayquerías) is a Late Miocene fossiliferous geological formation of the Frontal Cordillera and Cuyo Basin of Argentina. The formation crops out in the central Mendoza Province.

The formation, with a maximum thickness of 126 metres (413 ft), comprises reddish mudstones with thin beds of tuffs and sandstones, deposited in a fluvial, environment. The tuff in the formation is dated to 5.84 ± 0.41 Ma, placing it in the Huayquerian SALMA, the age named after the formation by Kraglievitch in 1934.

The formation has provided fossils of the procyonid Cyonasua pascuali and the litoptern Huayqueriana cristata, named after the formation.

The Huayqueriás Formation, present in the Frontal Cordillera and the neighboring Cuyo Basin, was described in 1934 by Kraglievitch as the basis for the Huayquerian South American land mammal age. The name Huayquerías means "badlands".^[1] The formation comprises reddish mudstones with mudcracks, paleoburrows and ichnofossils of vertebrates. Thin sandstone layers of up to 12 centimetres (4.7 in) thick exist in the formation. An ashfall bed exists at 83 metres (272 ft) below the contact with the slightly angular unconformably^[2] overlying Tunuyán Formation in a total section of 126 metres (413 ft).^[3] The tuff has been dated using ⁴⁰K/⁴⁰Ar analysis to 5.84 ± 0.41 Ma.^[4]

The Huayquerías Formation has been used to define the Huayquerian South American land mammal age, ranging from 9.0 to 6.8 Ma. However, later analysis of the ashfall bed in the formation, provided a much younger age of 5.84 ± 0.41 Ma, extending the temporal range of the Huayquerian SALMAans until near the Miocene-Pliocene limit. The Huayqueriás Formation has provided fossils of Cyonasua pascuali,^[5] and the litoptern Huayqueriana cristata, the latter of which, named after the formation.^[1]

• South American land mammal age

Geology

• Garrido, Alberto C.; Bonini, Ricardo; Barbeau, David L. (2017), Paleoambiente, edad y vertebrados de la Formación Huayquerías, Mioceno Tardío, Provincia de Mendoza, Republica Argentina, XX Congreso Geológico Argentino, pp. 50–55, retrieved 2019-03-08
• Marshall, L.G.; Drake, Robert E.; Curtis, Garniss H. (1986), "⁴⁰K-⁴⁰Ar age calibration of late Miocene-Pliocene mammal-bearing Huayquerías and Tunuyán Formations, Mendoza Province, Argentina", Journal of Paleontology, 60 (2): 448–457, doi:10.1017/S002233600002196X, retrieved 2019-03-08
• Yrigoyen, Marcelo R (1993), "Revisión estratigráfica del Neogeno de las Huayquerías de Mendoza septentrional, Argentina", Ameghiniana, 31: 125–138, retrieved 2019-03-08

Paleontology

• Forasiepi, Analía M.; MacPhee, Ross D.E.; Hernández del Pino, Santiago; Schmidt, Gabriela I.; Amson, Eli; Grohé, Camille (2016), "Exceptional skull of Huayqueriana (Mammalia, Litopterna, Macraucheniidae) from the Late Miocene of Argentina: anatomy, systematics and paleobiological implications" (PDF), Bulletin of the American Museum of Natural History, 404: 1–76, doi:10.1206/0003-0090-404.1.1, retrieved 2018-10-01
• Linares, O.J (1981), "Tres nuevos carnivoros Procionidos fósiles del Mioceno de Norte y Sudamerica", Ameghiniana, 18: 113–121, retrieved 2019-03-08