Candeleros Formation

Candeleros Formation
Stratigraphic range: early Cenomanian ~99–97 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Candeleros Formation near Cerro El Vagon, Neuquen, Argentina
Type	Geological formation
Unit of	Neuquén Group  Río Limay Subgroup
Underlies	Huincul Formation
Overlies	Lohan Cura Formation
Thickness	300 m (980 ft)
Lithology
Primary	Eolian sandstone
Other	Conglomerate, siltstone, paleosol
Location
Coordinates	39°24′S 69°12′W / 39.4°S 69.2°W / -39.4; -69.2
Approximate paleocoordinates	46°30′S 45°30′W / 46.5°S 45.5°W / -46.5; -45.5
Region	Mendoza, Neuquén & Río Negro Provinces
Country	Argentina
Extent	Neuquén Basin
Type section
Named for	Candeleros Hill
Named by	Wichmann
Year defined	1929
Candeleros Formation (Argentina)

The Candeleros Formation (formerly known as the Candeleros Member of the "Río Limay Formation") is a geologic formation that crops out in the Río Negro, Neuquén, and Mendoza provinces of northern Patagonia, Argentina. It is the oldest formation in the Neuquén Group and belongs to the Rio Limay Subgroup. Formerly that subgroup was treated as a formation, and the Candeleros Formation was known as the Candeleros Member.^[1]

Description

The type locality of the Candeleros Formation is Candeleros Hill in Neuquén Province, after which the formation was named by Wichmann in 1929.^[2] This formation unconformably overlies the Lohan Cura Formation, and it is in turn overlain by the Huincul Formation, also a unit of the Neuquén Group. The sediments of the latter are of lighter greenish and yellow colors and the boundary between the Candeleros and Huincul formations is easily recognizable.^[3]

The Candeleros Formation is almost 300 metres (980 ft) thick in some sections. Overall, the formation represents a part of the ancient Kokorkom desert with braided river system, made up mostly of sandstones and conglomerates. There are also isolated sections that represent eolian (wind-blown) deposition, as well as siltstones deposited under swamp conditions. Paleosols (soil deposits) are common in some sections as well.^[1][3]

Fossil content

The Candeleros Formation has a very diverse fossil fauna, including:

• dipnoan fish (including Ceratodus argentinus)
• frogs (including Avitabatrachus)
• Rhynchocephalians (including Priosphenodon avelasi and Tika giacchinoi)
• primitive snakes (including Najash rionegrina)
• several turtles (including 2 species of Prochelidella)
• an azhdarchid pterosaur, the oldest known from South America^[4]
• rebbachisaurid sauropods (Limaysaurus, Nopcsaspondylus and Rayososaurus)
• titanosaurian sauropods (including Andesaurus and a second unnamed huge titanosaur)
• abelisaurid theropods (Ekrixinatosaurus and unnamed form^[5])
• a carcharodontosaurid (Giganotosaurus)
• a dromaeosaurid theropod (Buitreraptor gonzalezorum)
• an alvarezsauroid theropod (Alnashetri)
• a basal coelurosaur (Bicentenaria)
• Iguanodonts (including Bonaparteichnium)^[6]
• a notosuchian (Araripesuchus)
• a basal thyreophoran (Jakapil)^[7]
• cladotherian mammals (including Cronopio dentiacutus)
• ichnofossils of Sousaichnum monettae, Limayichnus major, Bonaparteichnum tali, Bressaniichnus patagonicus, Deferraiichnum mapuchense, Abelichnus astigarragae and Picunichnus benedettoi^[8]

In 2021, fossil material of a giant titanosaur sauropod, distinct from Andesaurus and probably exceeding Patagotitan in size, was described from the formation by Otero et al. (2021).^[9]

Amphibians

Frogs

Reptiles

Rhynchocephalians

Taxa	Species	Locality	Stratigraphic position	Material	Notes	Images
Priosphenodon	P. avelasi				An eilenodontine rhynchocephalian.
Tika	T. giacchinoi				A sphenodontine rhynchocephalian.

Fish

Dinosaurs

Ornithischians

Taxa	Species	Locality	Stratigraphic position	Material	Notes	Images
Bonaparteichnium	B. tali			Footprints.	An Iguanodont.
Jakapil[7]	J. Kaniukura	La Buitrera, Cerro Policía, La Escondida and El Pueblito.		MPCA-PV-630, a partial skeleton including several osteoderms and a complete lower jaw.	A basal thyreophoran.

Saurischians

Sauropods

Taxa	Species	Locality	Stratigraphic position	Material	Notes	Images
Andesaurus	A. delgadoi			A partial skeleton.	A titanosaur.
Limaysaurus	L. tessonei				A rebbachisaurid sauropod.
Nopcsaspondylus	N. alarconensis				A rebbachisaurid sauropod.
Rayososaurus	R. agrioensis				A rebbachisaurid sauropod.
Titanosauria	indeterminate.

Theropods

Taxa	Species	Locality	Stratigraphic position	Material	Notes	Images
Abelichnus	A. astigerrae			A footprint.
Alnashetri	A. cerropoliciensis	La Buitrera	Rio Negro	The holotype consists of a partial left femur, distal portions of left and right tibiae, right fibula, proximal tarsals of both ankles, a nearly complete right metatarsus, proximal and distal parts of the left metapodials, and left pedal digit III.	An alvarezsauroid theropod.
Bicentenaria	B. argentina	Ezequiel Ramos Mexia Reservoir	Rio Negro province.	Several paratypes consist of fragments of two premaxillae with three pairs of teeth; a piece of upper right jawbone with a tooth; pieces of seventeen vertebrae; fourteen sacral vertebrae; twenty caudal vertebrae; pieces of two shoulder blades; an upper back corner of a right raven's jawbone; the tops of three ulna; the end of a spoke bone; eight hand claws; pieces of a left femur; five upper shafts of pubic bones; five partial femurs; the tops of two left tibias; the underside of a right tibia; a right tibia; pieces of five metatarsals; fifteen phalanges, separately eight-foot claws and pieces of rib.	A coelurosaur.
Buitreraptor	B. gonzalezorum	La Buitrera	Rio Negro province.	A partial skeleton along with several other paratypes such as a sacrum with a right pelvis, right hindlimb, and a skull.	A dromaeosaurid theropod.
Ekrixinatosaurus	E. novasi	Bajo del Añelo	Río Negro, Neuquén and Mendoza provinces.	A preserved skeleton.	An Abelisaurid theropod.
Giganotosaurus	G. carolinii	Los Candeleros, and Villa El Chocón.	Lowest unit in the Neuquén Group.	A partial skull, and a disarticulated postcranial skeleton which includes a vertebral column, pectoral and pelvic girdles, the femora, and the left tibia and fibula.	A carcharodontosaurid theropod.

Mammals

Taxa	Species	Locality	Stratigraphic position	Material	Notes	Images
Cronopio	C. dentiacutus	La Buitrera.	Neuquén Group.	Paratypes consist of a partial skull without skull roof, basicranium, and squamosals, a partial left lower jaw with damaged teeth, and an incomplete skull with a relatively complete right lower jaw missing some teeth.	A small insectivorous mammal that belongs to the Meridiolestida family.

Reptiles

Taxa	Species	Locality	Stratigraphic position	Material	Notes	Images
Araripesuchus	A. buitreraensis				A small Crocodyliform reptile.
	A. patagonicus
Prochelidella	P. buitreraensis	La Buitrera.	Rio Negro province.	A complete cranium skull.	A chelid tortoise.
Najash	N. rionegrina				A basal snake.

See also

• List of fossil sites
• Bajo Barreal Formation, contemporaneous fossiliferous formation of the San Jorge Basin
• Cerro Fortaleza Formation, contemporaneous fossiliferous formation of the Austral Basin
• Alcântara Formation, contemporaneous fossiliferous formation of the São Luís-Grajaú Basin, Brazil
• List of dinosaur bearing rock formations

References

Wikimedia Commons has media related to Candeleros Formation.

Bibliography

• Otero, A.; Carballido, J. L.; Salgado, L.; Canudo, J. I.; Garrido, A. C. (2021). "Report of a giant titanosaur sauropod from the Upper Cretaceous of Neuquén Province, Argentina". Cretaceous Research. 122: Article 104754. doi:10.1016/j.cretres.2021.104754. S2CID 233582290. doi:10.1016/j.cretres.2021.104754
• Canale, Juan I.; Cerda, Ignacio; Novas, Fernando E.; Haluza, Alejandro (2016). "Small-sized abelisaurid (Theropoda: Ceratosauria) remains from the Upper Cretaceous of northwest Patagonia, Argentina". Cretaceous Research. 62: 18–28. doi:10.1016/j.cretres.2016.02.001. doi:10.1016/j.cretres.2016.02.001
• Sánchez, María Lidia; Heredia, Susana; Calvo, Jorge O. (2006). "Paleoambientes sedimentarios del Cretácico Superior de la Formación Plottier (Grupo Neuquén), Departamento Confluencia, Neuquén (Sedimentary paleoenvironments in the Upper Cretaceous Plottier Formation (Neuquen Group), Confluencia, Neuquén)". Revista de la Asociación Geológica Argentina. 61: 3–18. Retrieved 2019-02-16.
• Leanza, H.A.; Apesteguia, S.; Novas, F.E.; De la Fuente, M.S. (2004). "Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages". Cretaceous Research. 25: 61–87. doi:10.1016/j.cretres.2003.10.005. Retrieved 2019-02-16.
• Leonardi, Giuseppe (1994). "Annotated Atlas of South America Tetrapod Footprints (Devonian to Holocene) with an appendix on Mexico and Central America". Ministerio de Minas e Energia - Companhia de Pesquisa de Recursos Minerais, Geological Service of Brazil. pp. 1–248. Retrieved 2019-03-25.
• Wichmann, R (1929). "Los Estratos con Dinosaurios y su techo en el este del Territorio del Neuquén ("The dinosaur-bearing strata and their upper limit in eastern Neuquén Territory")". Dirección General de Geología, Minería e Hidrogeología Publicación. 32: 1–9.

This page was last edited on 12 April 2024, at 15:32