Pebas Formation
| Pebas Formation Stratigraphic range: Early Aquitanian-Tortonian (Colhuehuapian-Huayquerian) ~ | |
|---|---|
 The Pebas Mega-Wetland (or ), in the middle of this map, corresponds to the Pebas Formation | |
| Underlies | |
| Overlies | |
| Area | 1,000,000 km2 (390,000 sq mi) |
| Thickness | ~350–1,074 m (1,148–3,524 ft) |
| Lithology | |
| Primary | Siltstone, mudstone |
| Other | Coal/lignite |
| Location | |
| Coordinates | 7°24′S 75°00′W / 7.4°S 75.0°WCoordinates: 7°24′S 75°00′W / 7.4°S 75.0°W |
| Approximate paleocoordinates | 8°24′S 70°36′W / 8.4°S 70.6°W |
| Region | Amazon Basin |
| Country |  Brazil Colombia Ecuador Peru |
| Type section | |
| Named for | Pebas District |
The Pebas Formation is a lithostratigraphic unit of Miocene age, found in western Amazonia. The formation extends over 1,000,000 square kilometres (390,000 sq mi), including parts of Brazil, Peru, Ecuador and Colombia.[1] It is interpreted as representing the deposits of a lake ("Lake Pebas") or series of lakes, formed within the foreland basin of the Andes mountain belt. It is known for its abundant fossil ostracods and molluscs and an unusually diverse group of crocodylians.[2]
Fossil content[]
| Group | Fossils | Notes |
|---|---|---|
| Mammals | Dinomyidae indet., ?Octodontoidea indet. | |
| Reptiles | Caiman wannlangstoni, Gnatusuchus pebasensis, Gryposuchus pachakamue, Purussaurus neivensis, Kuttanacaiman iquitosensis, Mourasuchus atopus, Paleosuchus sp., Podocnemis sp., Gavialoidea indet. | |
| Fishes | cf. Hydrolycus sp., Leporinus sp., Potamotrygon sp., Pristis sp., Anostomidae indet. | |
| Insects | Macroteleia yaguarum, |
Correlations[]
Laventan[]
| Formation | Honda | Cura-Mallín | Pisco | Pebas | Urumaco | Map | ||||||
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| Basin | San Rafael | Caldera | Pisco | Amazon | Venezuela | Paraná |      Pebas Formation (South America) | |||||
| Country | Colombia |
 Bolivia |
 Argentina |
 Chile |
Peru |
 Venezuela |
Argentina
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| Boreostemma |  |
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| Hapalops | |
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| Miocochilius | |
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| Theosodon | |
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| Xenastrapotherium | |
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| Sparassodonta | |
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| Environments | Fluvial | Fluvio-deltaic | Fluvio-lacustrine | Fluvio-deltaic | Fluvial |  Laventan volcanoclastics Laventan fauna Laventan flora | ||||||
| Volcanic | Yes | |||||||||||
Huayquerian[]
| Formation | Cerro Azul | Ituzaingó | Pebas | Urumaco | Map | ||||||||||||
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| Basin | Colorado | Paraná | Tontal | Salta | Amazon | Altiplano | BA | Velasco |   Pebas Formation (South America) | ||||||||
| Country | Argentina |
 Uruguay |
Argentina |
Brazil Peru |
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| Lagostomus | |
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| Thylacosmilus | |
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| Xotodon | |
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| Environments | Aeolian-fluvial | Fluvio-deltaic | Fluvial | Fluvio-lacustrine | Fluvial | Fluvio-lacustrine | Fluvio-deltaic | Huayquerian volcanoclastics Huayquerian fauna Huayquerian flora | |||||||||
| Volcanic | Yes | ||||||||||||||||
References[]
- ^ Wesselingh et al., 2006
- ^ Sala Gismondi et al., 2006
- ^ a b c CTA-45 at Fossilworks.org
- ^ IQ114 at Fossilworks.org
- ^ Amazonian amber at Fossilworks.org
Bibliography[]
- ; ; , and . 2011. Geología de las Planchas 567, 568, 568bis, 569 and 569bis - 1:200,000, 1–187. Servicio Geológico Colombiano. Accessed 2018-06-01.
- ; ; ; ; , and . 2015. A Miocene hyperdiverse crocodylian community reveals peculiar trophic dynamics in proto-Amazonian mega-wetlands. Proceedings of the Royal Society B: Biological Sciences 282. 20142490. Accessed 2018-05-20.
- ; ; ; ; , and . 2006. The stratigraphy and regional structure of Miocene deposits in western Amazonia (Peru, Colombia and Brazil), with implications for late Neogene landscape evolution. Scripta Geologica 133. 291–322. Accessed 2017-08-15.
Further reading[]
- ; ; ; ; ; ; ; , and . 2016. A 60-million-year Cenozoic history of western Amazonian ecosystems in Contamana, eastern Peru. Gondwana Research 31. 30–59. Accessed 2020-03-19.
- Marcos C.Bissaro-Júnior, Leonardo Kerber, James L.Crowley, Ana M.Ribeiro, Renato P.Ghilardi, Edson Guilherme, Francisco R.Negri, Jonas P.Souza Filho, Annie S.Hsiou: "Detrital zircon U–Pb geochronology constrains the age of Brazilian Neogene deposits from Western Amazonia." Palaeogeography, Palaeoclimatology, Palaeoecology Volume 516, 15 February 2019, Pages 64–70 doi: 10.1016/j.palaeo.2018.11.032
Categories:
- Geologic formations of Brazil
- Geologic formations of Colombia
- Geologic formations of Ecuador
- Geologic formations of Peru
- Miocene Series of South America
- Huayquerian
- Chasicoan
- Mayoan
- Laventan
- Friasian
- Colloncuran
- Santacrucian
- Colhuehuapian
- Neogene Brazil
- Neogene Colombia
- Neogene Ecuador
- Neogene Peru
- Fossiliferous stratigraphic units of South America
- Paleontology in Brazil
- Paleontology in Colombia
- Paleontology in Ecuador
- Paleontology in Peru
- Siltstone formations
- Mudstone formations
- Coal formations
- Lacustrine deposits