| Bajada Colorada Formation | |
|---|---|
| Stratigraphic range:Late Berriasian-Early Valanginian ~140–134 Ma | |
| 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′S69°42′W / 39.8°S 69.7°W /-39.8; -69.7 |
| Approximate paleocoordinates | 38°48′S32°12′W / 38.8°S 32.2°W /-38.8; -32.2 |
| Region | Neuquén Province |
| Country | Argentina |
| Extent | Neuquén Basin |
| Type section | |
| Named by | Roll |
| Year defined | 1939 |
  Bajada Colorada Formation (Argentina) | |
TheBajada Colorada Formation is ageologic formation of the southernNeuquén Province in theNeuquén Basin of northernPatagonia,Argentina. The formation belongs to theMendoza Group and isLate Berriasian toEarly Valanginian in age. The formation is renowned for preserving fossil remains ofBajadasaurus pronuspinax, a genus ofdicraeosauriddinosaurs named after the formation.
The Bajada Colorada Formation, first defined by Roll in 1939, pertains to theMendoza Group.[1] It overlies theQuintuco andPicún Leufú Formations and is overlain by theAgrio Formation. The contact with the Agrio Formation isdiscordant and the unconformity has been dated to 134 Ma.[2] The formation is laterally equivalent with theMulichinco Formation.[3] The formation comprises red and greenish-brown, fine to coarse grainedconglomerates and thick-beddedsandstones with well-developed bands of light brownsiltstones and reddish, pinkish grey and purple-reddishclaystones.[4] The formation was deposited in afluvialenvironment, and the paleoenviroment resembled abraided river system with well-preserved channels andpaleosols.[5]
X-ray diffraction studies of sediments belonging to the Bajada Colorada Formation have revealed the presence ofsmectite,chlorite,illite andkaolinite.[1]
The formation has provided fossils of:[6]
Color key
| Notes Uncertain or tentative taxa are insmall text; |
| Ornithischians of the Bajada Colorada Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Ankylosauria Indet.[7] | Indeterminate | |||||
| Sauropods of the Bajada Colorada Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Bajadasaurus[8] | B. pronuspinax | Adicraeosauridsauropod | ||||
| Leinkupal[9] | L. laticauda | Adiplodocinediplodocid | ||||
| Ninjatitan[10] | N. zapatai | Atitanosauriansauropod | ||||
| Theropods of the Bajada Colorada Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Abelisauridae Indet.[11] | Indeterminate | |||||
| Abelisauroidea Indet. | Indeterminate | |||||
| Deinonychosauria Indet. | Indeterminate | |||||
| Tetanurae Indet. | Indeterminate | |||||