Pebas Formation
Geological formation in Brazil, Colombia, Ecuador and Peru
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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]
UnderliesMarañón Formation
OverliesChambira Formation
Area1,000,000 km2 (390,000 sq mi)
Thickness~350–1,074 m (1,148–3,524 ft)
| Pebas Formation | |
|---|---|
| Stratigraphic range: Early Aquitanian-Tortonian (Colhuehuapian-Huayquerian) ~ | |
The Pebas Mega-Wetland (or Lake Pebas), on the western side of this map, corresponds to the Pebas Formation | |
| Underlies | Marañón Formation |
| Overlies | Chambira Formation |
| 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 | 7.4°S 75.0°W |
| Approximate paleocoordinates | 8.4°S 70.6°W |
| Region | Amazon Basin |
| Country | Brazil Colombia Ecuador Peru |
| Type section | |
| Named for | Pebas District |
Fossil content
Fish
| Taxa | Species | Locality | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
| Anostomidae | Indeterminate | |||||
| Hydrolycus[3] | cf. H. sp. | |||||
| Leporinus[3] | L. sp. | |||||
| Pristis[3] | P. sp. | |||||
| Potamotrygon[3] | P. sp. |
Insects
| Taxa | Species | Locality | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
| Macroteleia | M. yaguarum | A parasitoid wasp. | .jpg) | |||
| Sycorax | S. peruensis | Relatives of moth flies and sand flies. | ||||
Mammals
| Taxa | Species | Locality | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
| Dinomyidae | indeterminate | A hystricognath rodent. | ||||
| Octodontoidea | Indeterminate. | A hystricognath rodent. | ||||
| Neoepiblema[5] | N. sp. | A hystricognath rodent. | ||||
| Pebanista | P. yacuruna | Rio Napo. | A nearly complete skull. | A platanistid river dolphin. |  | |
| Pseudoprepotherium | P. sp. | Rio Napo | A ground sloth. | |||
| Potamarchus | P. sp | A hystricognath rodent. | ||||
| Parapropalaehoplophorus | P. sp | a glyptodont |
Reptiles
| Taxa | Species | Locality | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
| Caiman | C. wannlangstoni | Locality IQ26 and IQ114 | A well-preserved partial skull. | An extinct caiman |  | |
| Gavialoidea | Indeterminate. | |||||
| Gnatusuchus | G. pebasensis | Locality IQ114, IQ116, and IQ125 | Upper | A nearly complete skull. | A clam eating caiman. |  |
| Gryposuchus | G. pachakamue | Locality IQ101 | A gavialid crocodilian. |
 | ||
| Kuttanacaiman | K. iquitosensis | Locality IQ26 and IQ116 | Middle | nearly complete skull and mandibles. | A small caiman. |  |
| Chelus | C. colombianus | Pieces of shell bones and scutes | A slightly larger species of mata mata, reaching an estimated shell length of up to a meter. | |||
| Mourasuchus | M. atopus | Locality IQ114 | ||||
| Paleosuchus | P. sp. | |||||
| Podocnemis | P. sp. | |||||
| Purussaurus | P. neivensis | Locality IQ26 and IQ114 | Skull and teeth. | A giant caiman. |  |
Correlations
Laventan
| Formation | Honda | Honda | Aisol | Cura-Mallín | Pisco | Ipururo | Pebas | Capadare | Urumaco | Inés | Paraná | Map |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Basin | VSM | Honda | San Rafael | Caldera | Pisco | Ucayali | Amazon | Falcón | Venezuela | Paraná |     Pebas Formation (South America) | |
| Country |  Colombia |  Bolivia |  Argentina |  Chile |  Peru |  Venezuela | Argentina | |||||
| Boreostemma |  | | | |||||||||
| Hapalops | | | | |||||||||
| Miocochilius | | | | |||||||||
| Theosodon | | | | |||||||||
| Xenastrapotherium | | | | |||||||||
| Mylodontidae | | | | | ||||||||
| Sparassodonta | | | ||||||||||
| Primates |  | |||||||||||
| Rodents |  | | | | | | | |||||
| Birds |  | | | |||||||||
| Terror birds |  | |||||||||||
| Reptiles |  | | | | | | | |||||
| megalodon |  | | | |||||||||
| Flora |  | |||||||||||
| Insects |  | |||||||||||
| Environments | Fluvial | Fluvio-deltaic | Fluvio-lacustrine | Fluvio-deltaic | Fluvial |  Laventan volcanoclastics Laventan fauna Laventan flora | ||||||
| Volcanic | Yes | |||||||||||
Huayquerian
| Formation | Cerro Azul | Ituzaingó | Paraná | Camacho | Raigón | Andalhuala | Chiquimil | Las Flores | Maimará | Palo | Pebas | Muyu | Rosa | Saldungaray | Salicas | Urumaco | Map |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Basin | Colorado | Paraná | Hualfín | Tontal | Andes | Salta | Amazon | Huasi | Altiplano | BA | Velasco | Falcón |  Pebas Formation (South America) | ||||
| Country | Argentina |  Uruguay | Argentina |  Brazil Peru | Bolivia | Argentina | Venezuela | ||||||||||
| Cardiatherium |  | | | | |||||||||||||
| Lagostomus | | | | | | | |||||||||||
| Macroeuphractus | | | | ||||||||||||||
| Proeuphractus | | | | | |||||||||||||
| Pronothrotherium | | | |||||||||||||||
| Pseudotypotherium | | | | ||||||||||||||
| Thylacosmilus | | | | ||||||||||||||
| Xotodon | | | | | |||||||||||||
| Macraucheniidae | | | | | | | |||||||||||
| Primates | | ||||||||||||||||
| Rodents | | | | | | | | | | | | ||||||
| Reptiles | | | | | | | |||||||||||
| Birds | | | | | |||||||||||||
| Terror birds | | | | ||||||||||||||
| Flora | | | |||||||||||||||
| Environments | Aeolian-fluvial | Fluvio-deltaic | Fluvial | Fluvio-lacustrine | Fluvial | Fluvio-lacustrine | Fluvio-deltaic | Huayquerian volcanoclastics Huayquerian fauna Huayquerian flora | |||||||||
| Volcanic | Yes | ||||||||||||||||