Bajada Colorada Formation

Bajada Colorada Formation
Bajada Colorada Formation
Stratigraphic range: Late Berriasian-Early Valanginian; ~140–134 Ma PreꞒ Ꞓ O S D C P T J K Pg N B V H B Apt. Albian C T C S Cam. M
Type	Geological formation
Unit of	Mendoza Group
Underlies	Agrio Formation
Overlies	Quintuco & Picún Leufú Formations
Lithology
Primary	Sandstone, conglomerate
Other	Siltstone, claystone
Location
Coordinates	39°48′S 69°42′W / 39.8°S 69.7°W
Approximate paleocoordinates	38°48′S 32°12′W / 38.8°S 32.2°W
Region	Neuquén Province
Country	Argentina
Extent	Neuquén Basin
Type section
Named by	Roll
Year defined	1939
	Bajada Colorada Formation (Argentina)

The Bajada Colorada Formation is a geologic formation of the southern Neuquén Province in the Neuquén Basin of northern Patagonia, Argentina. The formation belongs to the Mendoza Group and is late Berriasian to early Valanginian in age. The formation is renowned for preserving fossil remains of Bajadasaurus pronuspinax, a genus of dicraeosaurid dinosaurs named after the formation.

Description

The Bajada Colorada Formation, first defined by Roll in 1939, pertains to the Mendoza Group. It overlies the Quintuco and Picún Leufú Formations and is overlain by the Agrio Formation. The contact with the Agrio Formation is discordant and the unconformity has been dated to 134 Ma. The formation is laterally equivalent with the Mulichinco Formation. The formation comprises red and greenish-brown, fine to coarse grained conglomerates and thick-bedded sandstones with well-developed bands of light brown siltstones and reddish, pinkish grey and purple-reddish claystones. The formation was deposited in a fluvial environment, and the paleoenviroment resembled a braided river system with well-preserved channels and paleosols.

X-ray diffraction studies of sediments belonging to the Bajada Colorada Formation have revealed the presence of smectite, chlorite, illite and kaolinite.

Fossil content

The formation has provided fossils of:

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative taxa are in small text
~~crossed out~~ taxa are discredited.

Dinosaurs

Ornithischians

Ornithischians of the Bajada Colorada Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Ankylosauria Indet.	Indeterminate			Isolated scutes
Stegosauria Indet.	Indeterminate			Sacral vertebrae, dorsal ribs and osteoderms

Sauropods

Sauropods of the Bajada Colorada Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Bajadasaurus	B. pronuspinax			A nearly complete skull, both proatlases, atlantal neurapophyses, axis and the ?fifth cervical vertebra.	A dicraeosaurid sauropod
Leinkupal	L. laticauda			Cervical, dorsal caudal vertebrae remains and a braincase	A diplodocine diplodocid
Ninjatitan	N. zapatai			Partial postcranial skeleton, anterior caudal vertebra of the holotype might represent diplodocoid sauropod.	A titanosaurian sauropod

Theropods

Theropods of the Bajada Colorada Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Abelisauridae Indet.	Indeterminate			Proximal half of a left tibia
Abelisauroidea Indet.	Indeterminate			Am almost complete axis (MMCh-PV 67) and two isolated caudal centra (MMCh-PV 76 and 77)
Megalosauridae Indet.	Indeterminate			Dental remains
Theropoda Indet.	Indeterminate			Dental remains	3 different morphotypes are present.

References

1 2 Moyano Bohórquez, 2004
↑ Leanza, 2005, p.151
↑ Howell et al., 2005, p.4
↑ Leanza et al., 2011, p.120
↑ Gallina et al., 2014, p.2
↑ Bajada Colorada locality at Fossilworks.org
↑ Rozadilla, Sebastián; Agnolín, Federico; Manabe, Makoto; Tsuihiji, Takanobu; Novas, Fernando E. (September 2021). "Ornithischian remains from the Chorrillo Formation (Upper Cretaceous), southern Patagonia, Argentina, and their implications on ornithischian paleobiogeography in the Southern Hemisphere". Cretaceous Research. 125 104881. Bibcode:2021CrRes.12504881R. doi:10.1016/j.cretres.2021.104881.
↑ Riguetti, F. J.; Apesteguía, S.; Canale, J. I.; Gallina, P. A. (2026). "New thyreophoran remains with stegosaurian affinities from the Lower Cretaceous of Argentina". Publicación Electrónica de la Asociación Paleontológica Argentina. 26 (1): 56–79. doi:10.5710/PEAPA.25.11.2025.551.
↑ Pablo A. Gallina; Sebastián Apesteguía; Juan I. Canale; Alejandro Haluza (2019). "A new long-spined dinosaur from Patagonia sheds light on sauropod defense system". Scientific Reports. 9 (1) 1392. Bibcode:2019NatSR...9.1392G. doi:10.1038/s41598-018-37943-3. PMC 6362061. PMID 30718633.
↑ Pablo A. Gallina; Sebastián Apesteguía; Alejandro Haluza; Juan I. Canale (2014). "A Diplodocid Sauropod Survivor from the Early Cretaceous of South America". PLOS ONE. 9 (5) e97128. Bibcode:2014PLoSO...997128G. doi:10.1371/journal.pone.0097128. PMC 4020797. PMID 24828328.
↑ Gallina PA, Canale JI, Carballido JL (2021-02-28). "The Earliest Known Titanosaur Sauropod Dinosaur". Ameghiniana. 58 (1): 35–51. doi:10.5710/AMGH.20.08.2020.3376. ISSN 1851-8044. S2CID 226680080.
1 2 3 4 Juan I. Canale; S. Apesteguía; P.A. Gallina; F.A. Gianechini; A. Haluza (2017). "The oldest theropods from the Neuquén Basin: Predatory dinosaur diversity from the Bajada Colorada Formation (Lower Cretaceous: Berriasian–Valanginian), Neuquén, Argentina". Cretaceous Research. 71: 63–78. Bibcode:2017CrRes..71...63C. doi:10.1016/j.cretres.2016.11.010. hdl:11336/109121.

Bibliography

Gallina, Pablo A.; Apesteguía, Sebastián; Haluza, Alejandro; Canale, Juan I. (2014), "A Diplodocid Sauropod Survivor from the Early Cretaceous of South America", PLoS ONE, 9 (5) e97128, Bibcode:2014PLoSO...997128G, doi:10.1371/journal.pone.0097128, hdl:11336/6526, PMC 4020797, PMID 24828328
Howell, John A.; Schwartz, Ernesto; Spalletti, Luis A.; Veiga, Gonzalo D. (2005), "The Neuquén Basin: An overview", Geological Society, London, Special Publications, 252 (1): 1–14, Bibcode:2005GSLSP.252....1H, doi:10.1144/GSL.SP.2005.252.01.01, hdl:11336/108392, retrieved 2019-02-14
Leanza, Héctor A.; Sattler, Federico; Martínez, Ricardo S.; Carbone, Osvaldo (2011), La formación Vaca Muerta y equivalentes (Jurásico tardío-Cretácico temprano) en la Cuenca Neuquina, XVIII Congreso Geológico Argentino, pp. 113–129, retrieved 2019-02-14
Leanza, Héctor A (2005), "Las principales discordancias del Jurásico Superior y el Cretácico de la Cuenca Neuquina", Anales de la Academia Nacional de Ciencias Exactas, Físicas y Naturales, 57: 147–155, retrieved 2019-02-14
Moyano Bohórquez, Fernando (2004), Los sistemas sedimentarios de la Formación Bajada Colorada (Cretácico Temprano) en el sur de la Cuenca Neuquina, Argentina, Universidad Nacional de La Plata, pp. 1–250, retrieved 2019-02-14

[Moyano2004-1] 1 2 Moyano Bohórquez, 2004

[Leanza2005_p151-2] Leanza, 2005, p.151

[Howell2005_p4-3] Howell et al., 2005, p.4

[Leanza2011_p120-4] Leanza et al., 2011, p.120

[Gallina2014_p2-5] Gallina et al., 2014, p.2

[FWBajadaColorada-6] Bajada Colorada locality at Fossilworks.org

[7] Rozadilla, Sebastián; Agnolín, Federico; Manabe, Makoto; Tsuihiji, Takanobu; Novas, Fernando E. (September 2021). "Ornithischian remains from the Chorrillo Formation (Upper Cretaceous), southern Patagonia, Argentina, and their implications on ornithischian paleobiogeography in the Southern Hemisphere". Cretaceous Research. 125 104881. Bibcode:2021CrRes.12504881R. doi:10.1016/j.cretres.2021.104881.

[8] Riguetti, F. J.; Apesteguía, S.; Canale, J. I.; Gallina, P. A. (2026). "New thyreophoran remains with stegosaurian affinities from the Lower Cretaceous of Argentina". Publicación Electrónica de la Asociación Paleontológica Argentina. 26 (1): 56–79. doi:10.5710/PEAPA.25.11.2025.551.

[9] Pablo A. Gallina; Sebastián Apesteguía; Juan I. Canale; Alejandro Haluza (2019). "A new long-spined dinosaur from Patagonia sheds light on sauropod defense system". Scientific Reports. 9 (1) 1392. Bibcode:2019NatSR...9.1392G. doi:10.1038/s41598-018-37943-3. PMC 6362061. PMID 30718633.

[10] Pablo A. Gallina; Sebastián Apesteguía; Alejandro Haluza; Juan I. Canale (2014). "A Diplodocid Sauropod Survivor from the Early Cretaceous of South America". PLOS ONE. 9 (5) e97128. Bibcode:2014PLoSO...997128G. doi:10.1371/journal.pone.0097128. PMC 4020797. PMID 24828328.

[11] Gallina PA, Canale JI, Carballido JL (2021-02-28). "The Earliest Known Titanosaur Sauropod Dinosaur". Ameghiniana. 58 (1): 35–51. doi:10.5710/AMGH.20.08.2020.3376. ISSN 1851-8044. S2CID 226680080.

[CAGGH17-12] 1 2 3 4 Juan I. Canale; S. Apesteguía; P.A. Gallina; F.A. Gianechini; A. Haluza (2017). "The oldest theropods from the Neuquén Basin: Predatory dinosaur diversity from the Bajada Colorada Formation (Lower Cretaceous: Berriasian–Valanginian), Neuquén, Argentina". Cretaceous Research. 71: 63–78. Bibcode:2017CrRes..71...63C. doi:10.1016/j.cretres.2016.11.010. hdl:11336/109121.