# Quebrada del Barro Formation

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Geologic formation in Argentina

Quebrada del Barro Formation Stratigraphic range: Norian Type Geological formation Unit of Marayes Group Underlies Los Riscos Formation Overlies Carrizal Formation Lithology Primary Sandstone Other Siltstone Location Coordinates 31°54′S 67°12′W / 31.9°S 67.2°W / -31.9; -67.2 Approximate paleocoordinates 40°48′S 30°00′W / 40.8°S 30.0°W / -40.8; -30.0 Region San Juan Province Country Argentina Extent Marayes-El Carrizal Basin Quebrada del Barro Formation (Argentina)

The **Quebrada del Barro Formation** is a geological [formation](/source/Formation_(geology)) of the [Marayes-El Carrizal Basin](https://en.wikipedia.org/w/index.php?title=Marayes-El_Carrizal_Basin&action=edit&redlink=1) in [San Juan Province](/source/San_Juan_Province%2C_Argentina), [Argentina](/source/Argentina). This formation is the most fossiliferous portion of the Triassic [Marayes Group](https://en.wikipedia.org/w/index.php?title=Marayes_Group&action=edit&redlink=1), and is also the youngest unit of the group, overlying the [El Carrizal Formation](https://en.wikipedia.org/w/index.php?title=El_Carrizal_Formation&action=edit&redlink=1). An [unconformity](/source/Unconformity) at the top of the Quebrada del Barro Formation separates it from the [Cretaceous](/source/Cretaceous)-age [Los Riscos Formation](https://en.wikipedia.org/w/index.php?title=Los_Riscos_Formation&action=edit&redlink=1) of the [El Gigante Group](https://en.wikipedia.org/w/index.php?title=El_Gigante_Group&action=edit&redlink=1).[1][2][3][4] Part of the formation may be made into a provincial park following the discovery of the fossils of *[Ingentia](/source/Ingentia)*, a giant sauropodomorph dinosaur which helped elucidate the early evolution of [sauropods](/source/Sauropoda).[5]

## Sedimentology

The Quebrada del Barro Formation formed within a [rift basin](/source/Rift) during a period of renewed fracturing. It encompasses 600 to 1,400 metres (2,000 to 4,600 ft) of red [sandstones](/source/Sandstone), fine [conglomerates](/source/Conglomerate_(geology)), and [diamictites](/source/Diamictite).[3] Early hypotheses on the depositional environment proposed that the sediments formed in an [alluvial fan](/source/Alluvial_fan) or [braided river](/source/Braided_river) system, while a newer proposal outlines how four different [facies](/source/Facies) within the formation can be used to reconstruct a meandering [semiarid](/source/Semi-arid_climate) floodplain deposited by [mudflows](/source/Mudflow) and discharging in [heterolithic](/source/Heterolithic_bedding) [terminal splays](https://en.wikipedia.org/w/index.php?title=Terminal_splays&action=edit&redlink=1).[6]

## Fossil content

The fauna of Quebrada del Barro is similar to that of the neighboring [Los Colorados Formation](/source/Los_Colorados_Formation) which is considered to be from the [Norian](/source/Norian) stage of the Late Triassic.[7] Both formations preserve fossils from groups such as [sauropodomorph](/source/Sauropodomorpha) [dinosaurs](/source/Dinosaur), [cynodonts](/source/Cynodont), and [testudinatans](/source/Testudinata). However, Quebrada del Barro is more abundant in [sphenodontians](/source/Rhynchocephalia) (*[Sphenotitan](/source/Sphenotitan)*), [tritheledontid](/source/Tritheledontidae) cynodonts, and [coelophysoid](/source/Coelophysoidea) dinosaurs (*[Lucianovenator](/source/Lucianovenator)*), while sauropodomorphs are somewhat less common and [aetosaurs](/source/Aetosaur) are completely absent, in contrast to the Los Colorados Formation.[3] Sphenodontians and cynodonts are also abundant in microfossil assemblages.[6] In addition, the Quebrada del Barro Formation preserves some of the only [pterosaur](/source/Pterosaur) and *[Dromomeron](/source/Dromomeron)* specimens known from Triassic strata in Argentina. Although the sphenodontian and cynodont-dominated fauna of Quebrada del Barro is akin to that of the Faxinal del Sotorno assemblage of the [Brazilian](/source/Brazil) [Caturrita Formation](/source/Caturrita_Formation), the fauna of the Faxinal del Sotorno assemblage is otherwise indicative of an older part of the Triassic than the Quebrada del Barro Formation.[3]

### Dinosaurs

Theropods of the Quebrada del Barro Formation Genus Species Material Notes Images Lucianovenator[8] L. bonoi Several specimens including vertebrae, hip fragments, and a partial tibia A coelophysid theropod

Sauropodomorphs of the Quebrada del Barro Formation Taxon Species Material Notes Images Ingentia[9] I. prima "cervical and dorsal vertebrae, scapula" A lessemsaurid sauropod Leyesaurus[2] L. marayensis A massospondylid sauropodomorph. Known from uppermost layers which may belong to a different unit of Hettangian (Early Jurassic) age.[3] Sauropodomorpha sp. Complete foot and tail vertebrae Undiagnostic sauropodomorph remains originally referred to Riojasaurus[2][10]

### Other [avemetatarsalians](/source/Avemetatarsalian)

Non-dinosaur avemetatarsalias of the Quebrada del Barro Formation Taxon Species Material Notes Images Dromomeron[11] D. gigas A partial femur a lagerpetid Pachagnathus P. benitoi Snout fragment A raeticodactylid pterosaur[12] Pterosauria sp. Partial ulna an indeterminate pterosaur[3] Yelaphomte Y. praderioi Snout fragment A raeticodactylid pterosaur[12]

### Pseudosuchians

Pseudosuchias of the Quebrada del Barro Formation Taxon Species Material Notes Images "Rauisuchidae" sp. Skull fragments, osteoderms an indeterminate "rauisuchid" smaller than Fasolasuchus[3] Crocodylomorpha sp. A specimen including a partial osteoderm and vertebrae fragments Indeterminate, possibly a "sphenosuchid"[3] Crocodylomorpha sp. Two incomplete specimens including osteoderms, vertebrae, and other bones a protosuchid, possibly synonymous with Hemiprotosuchus[3]

### Rhynchocephalians

Rhynchocephalians of the Quebrada del Barro Formation Genus Species Material Notes Images Sphenotitan[13] S. leyesi numerous specimens (~50% of all recovered fossils)[3] an eilenodontine sphenodontian

### Other reptiles

Other reptiles of the Quebrada del Barro Formation Taxon Species Material Notes Images Archosauriformes sp. Maxilla, caudal vertebra, metatarsal, indeterminate limb bone (tibia?) Various indeterminate fragments likely belonging to pseudosuchians or dinosauromorphs[4] Waluchelys W. cavitesta 2 partial skeletons and carapaces an australochelyid stem-turtle[14][3]

### Synapsids

Synapsids of the Quebrada del Barro Formation Taxon Species Material Notes Images Tritheledontidae sp. 36 specimens, including a partial skeleton an undescribed tritheledontid cynodont. May be two taxa based on two morphotypes: "long-snout" and "short-snout".[3]

## References

1. **[^](#cite_ref-Gardini2009_p554_1-0)** Gardini et al., 2009, p.554

1. ^ [***a***](#cite_ref-Leyesaurus_2-0) [***b***](#cite_ref-Leyesaurus_2-1) [***c***](#cite_ref-Leyesaurus_2-2) Cecilia Apaldetti; Ricardo N. Martinez; Oscar A. Alcober; Diego Pol (2011). Claessens, Leon (ed.). ["A New Basal Sauropodomorph (Dinosauria: Saurischia) from Quebrada del Barro Formation (Marayes-El Carrizal Basin), Northwestern Argentina"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3212523). *PLOS ONE*. **6** (11) e26964. [Bibcode](/source/Bibcode_(identifier)):[2011PLoSO...626964A](https://ui.adsabs.harvard.edu/abs/2011PLoSO...626964A). [doi](/source/Doi_(identifier)):[10.1371/journal.pone.0026964](https://doi.org/10.1371%2Fjournal.pone.0026964). [PMC](/source/PMC_(identifier)) [3212523](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3212523). [PMID](/source/PMID_(identifier)) [22096511](https://pubmed.ncbi.nlm.nih.gov/22096511).

1. ^ [***a***](#cite_ref-Martinez2015_3-0) [***b***](#cite_ref-Martinez2015_3-1) [***c***](#cite_ref-Martinez2015_3-2) [***d***](#cite_ref-Martinez2015_3-3) [***e***](#cite_ref-Martinez2015_3-4) [***f***](#cite_ref-Martinez2015_3-5) [***g***](#cite_ref-Martinez2015_3-6) [***h***](#cite_ref-Martinez2015_3-7) [***i***](#cite_ref-Martinez2015_3-8) [***j***](#cite_ref-Martinez2015_3-9) [***k***](#cite_ref-Martinez2015_3-10) [***l***](#cite_ref-Martinez2015_3-11) Martínez, Ricardo N.; Apaldetti, Cecilia; Correa, Gustavo; Colombi, Carina E.; Fernández, Eliana; Malnis, Paula Santi; Praderio, Angel; Abelín, Diego; Benegas, Laura G.; Aguilar-Cameo, Andrea; Alcober, Oscar A. (August 2015). ["A New Late Triassic Vertebrate Assemblage from Northwestern Argentina"](https://www.researchgate.net/publication/276133829). *Ameghiniana*. **52** (4): 379–390. [doi](/source/Doi_(identifier)):[10.5710/AMGH.27.04.2015.2889](https://doi.org/10.5710%2FAMGH.27.04.2015.2889). [hdl](/source/Hdl_(identifier)):[11336/111650](https://hdl.handle.net/11336%2F111650). [ISSN](/source/ISSN_(identifier)) [0002-7014](https://search.worldcat.org/issn/0002-7014). [S2CID](/source/S2CID_(identifier)) [131662341](https://api.semanticscholar.org/CorpusID:131662341).

1. ^ [***a***](#cite_ref-Archosauriformes2016_4-0) [***b***](#cite_ref-Archosauriformes2016_4-1) Gianechini, Federico A.; Codorniú, Laura; Arcucci, Andrea B.; Castillo Elías, Gabriela; Rivarola, David (March 2016). ["Archosauriform remains from the Late Triassic of San Luis province, Argentina, Quebrada del Barro Formation, Marayes–El Carrizal Basin"](https://www.researchgate.net/publication/288858161). *Journal of South American Earth Sciences*. **66**: 110–124. [Bibcode](/source/Bibcode_(identifier)):[2016JSAES..66..110G](https://ui.adsabs.harvard.edu/abs/2016JSAES..66..110G). [doi](/source/Doi_(identifier)):[10.1016/j.jsames.2015.12.012](https://doi.org/10.1016%2Fj.jsames.2015.12.012). [hdl](/source/Hdl_(identifier)):[11336/60591](https://hdl.handle.net/11336%2F60591). [ISSN](/source/ISSN_(identifier)) [0895-9811](https://search.worldcat.org/issn/0895-9811).

1. **[^](#cite_ref-5)** ["Uac wants a provincial park in the cradle of Ingenia Prima"](https://web.archive.org/web/20231126223425/https://naaju.com/argentina/uac-wants-a-provincial-park-in-the-cradle-of-ingenia-prima/). *Naaju*. Archived from [the original](http://naaju.com/argentina/uac-wants-a-provincial-park-in-the-cradle-of-ingenia-prima/) on 2023-11-26. Retrieved 2018-07-15.

1. ^ [***a***](#cite_ref-:0_6-0) [***b***](#cite_ref-:0_6-1) Colombi, Carina E.; Martínez, Ricardo N.; Correa, Gustavo; Fernández, Eliana; Malnis, Paula Santi; Praderio, Angel; Apaldetti, Cecilia; Abelín, Diego; Alcober, Oscar; Aguilar-Cameo, Andrea (October 2015). ["First Argentine Microfossil Bonebed from the Upper Triassic Marayes—El Carrizal Basin, San Juan Province"](https://www.researchgate.net/publication/283222785). *PALAIOS*. **30** (10): 743–757. [Bibcode](/source/Bibcode_(identifier)):[2015Palai..30..743C](https://ui.adsabs.harvard.edu/abs/2015Palai..30..743C). [doi](/source/Doi_(identifier)):[10.2110/palo.2014.055](https://doi.org/10.2110%2Fpalo.2014.055). [hdl](/source/Hdl_(identifier)):[11336/4899](https://hdl.handle.net/11336%2F4899). [ISSN](/source/ISSN_(identifier)) [0883-1351](https://search.worldcat.org/issn/0883-1351). [S2CID](/source/S2CID_(identifier)) [131239254](https://api.semanticscholar.org/CorpusID:131239254).

1. **[^](#cite_ref-triassicdistribution_7-0)** Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Triassic, South America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 527–528. [ISBN](/source/ISBN_(identifier)) [0-520-24209-2](https://en.wikipedia.org/wiki/Special:BookSources/0-520-24209-2).

1. **[^](#cite_ref-8)** Ricardo N. Martínez; Cecilia Apaldetti (2017). "A late Norian-Rhaetian coelophysid neotheropod (Dinosauria, Saurischia) from the Quebrada del Barro Formation, northwestern Argentina". Ameghiniana. in press. [doi:10.5710/AMGH.09.04.2017.3065](https://doi.org/10.5710/AMGH.09.04.2017.3065).

1. **[^](#cite_ref-apaldetti2018_9-0)** Apaldetti; Martínez, Ricardo N.; Cerda, Ignatio A.; Pol, Diego; Alcober, Oscar (2018). "An early trend towards gigantism in Triassic sauropodomorph dinosaurs". *Nature Ecology & Evolution*. **2** (8): 1227–1232. [Bibcode](/source/Bibcode_(identifier)):[2018NatEE...2.1227A](https://ui.adsabs.harvard.edu/abs/2018NatEE...2.1227A). [doi](/source/Doi_(identifier)):[10.1038/s41559-018-0599-y](https://doi.org/10.1038%2Fs41559-018-0599-y). [hdl](/source/Hdl_(identifier)):[11336/89332](https://hdl.handle.net/11336%2F89332). [PMID](/source/PMID_(identifier)) [29988169](https://pubmed.ncbi.nlm.nih.gov/29988169). [S2CID](/source/S2CID_(identifier)) [49669597](https://api.semanticscholar.org/CorpusID:49669597).

1. **[^](#cite_ref-ageofdinosaursriojasaurus_10-0)** "Riojasaurus." In: Dodson, Peter & Britt, Brooks & Carpenter, Kenneth & Forster, Catherine A. & Gillette, David D. & Norell, Mark A. & Olshevsky, George & Parrish, J. Michael & Weishampel, David B. *The Age of Dinosaurs*. Publications International, LTD. p. 41. [ISBN](/source/ISBN_(identifier)) [0-7853-0443-6](https://en.wikipedia.org/wiki/Special:BookSources/0-7853-0443-6).

1. **[^](#cite_ref-11)** Ricardo N. Martínez; Cecilia Apaldetti; Gustavo A. Correa; Diego Abelín (2016). "A Norian lagerpetid dinosauromorph from the Quebrada del Barro Formation, northwestern Argentina". *Ameghiniana*. **53** (1): 1–13. [doi](/source/Doi_(identifier)):[10.5710/AMGH.21.06.2015.2894](https://doi.org/10.5710%2FAMGH.21.06.2015.2894). [S2CID](/source/S2CID_(identifier)) [131613066](https://api.semanticscholar.org/CorpusID:131613066).

1. ^ [***a***](#cite_ref-:1_12-0) [***b***](#cite_ref-:1_12-1) Martínez, Ricardo N.; Andres, Brian; Apaldetti, Cecilia; Cerda, Ignacio A. (March 2022). ["The dawn of the flying reptiles: first Triassic record in the southern hemisphere"](https://onlinelibrary.wiley.com/doi/10.1002/spp2.1424). *Papers in Palaeontology*. **8** (2). [Bibcode](/source/Bibcode_(identifier)):[2022PPal....8E1424M](https://ui.adsabs.harvard.edu/abs/2022PPal....8E1424M). [doi](/source/Doi_(identifier)):[10.1002/spp2.1424](https://doi.org/10.1002%2Fspp2.1424). [ISSN](/source/ISSN_(identifier)) [2056-2799](https://search.worldcat.org/issn/2056-2799). [S2CID](/source/S2CID_(identifier)) [247494547](https://api.semanticscholar.org/CorpusID:247494547).

1. **[^](#cite_ref-Sphenotitan_13-0)** Martinez, R. N.; Apaldetti, C.; Colombi, C. E.; Praderio, A.; Fernandez, E.; Malnis, P. S.; Correa, G. A.; Abelin, D.; Alcober, O. (2013). ["A new sphenodontian (Lepidosauria: Rhynchocephalia) from the Late Triassic of Argentina and the early origin of the herbivore opisthodontians"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3813332). *Proceedings of the Royal Society B: Biological Sciences*. **280** (1772) 20132057. [doi](/source/Doi_(identifier)):[10.1098/rspb.2013.2057](https://doi.org/10.1098%2Frspb.2013.2057). [PMC](/source/PMC_(identifier)) [3813332](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3813332). [PMID](/source/PMID_(identifier)) [24132307](https://pubmed.ncbi.nlm.nih.gov/24132307).

1. **[^](#cite_ref-14)** Sterli, Juliana; Martínez, Ricardo N.; Cerda, Ignacio A.; Apaldetti, Cecilia (2021). ["Appearances can be deceptive: bizarre shell microanatomy and histology in a new Triassic turtle (Testudinata) from Argentina at the dawn of turtles"](https://onlinelibrary.wiley.com/doi/abs/10.1002/spp2.1334). *Papers in Palaeontology*. **7** (2): 1097–1132. [Bibcode](/source/Bibcode_(identifier)):[2021PPal....7.1097S](https://ui.adsabs.harvard.edu/abs/2021PPal....7.1097S). [doi](/source/Doi_(identifier)):[10.1002/spp2.1334](https://doi.org/10.1002%2Fspp2.1334). [ISSN](/source/ISSN_(identifier)) [2056-2802](https://search.worldcat.org/issn/2056-2802). [S2CID](/source/S2CID_(identifier)) [225515560](https://api.semanticscholar.org/CorpusID:225515560).

### Bibliography

- Gardini, Carlos; Rivarola, David; Agüera, Maximiliano; Candela, Gerónimo (2009). ["Estructura de la región Sierra de Guayaguas-Marayes, Provincias de San Juan y San Luis"](http://www.scielo.org.ar/pdf/raga/v65n3/v65n3a12.pdf) (PDF). *[Revista de la Asociación Geológica Argentina](/source/Revista_de_la_Asociaci%C3%B3n_Geol%C3%B3gica_Argentina)*. **65**: 551–565. Retrieved 2018-09-08.

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Adapted from the Wikipedia article [Quebrada del Barro Formation](https://en.wikipedia.org/wiki/Quebrada_del_Barro_Formation) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Quebrada_del_Barro_Formation?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.