| La Matilde Formation | |
| Type: | Geological formation |
| Period: | Kimmeridgian |
| Age: | Bathonian-Kimmeridgian ~ |
| Prilithology: | Claystone, sandstone, siltstone |
| Otherlithology: | Coal beds, conglomerate, tuff |
| Location: | Patagonia |
| Region: | Santa Cruz Province |
| Country: | Argentina |
| Coordinates: | -47.6°N -68.1°W |
| Paleocoordinates: | -44.2°N -27.3°W |
| Underlies: | San Julián Formation |
| Overlies: | Chon Aike Formation |
| Extent: | Austral Basin |
La Matilde Formation is a Jurassic geological formation in the Austral Basin of Santa Cruz Province, Patagonia, Argentina. It is dated to the Middle to Late Jurassic. From the Bathonian age (164.7 to 167.7 million years ago) to the Kimmeridgian age (150.8 to 155.7 million years ago) at the latest.[1] [2]
The area was once part of the subtropical and temperate regions of the southern supercontinent Gondwana in the Mesozoic era, a more or less continuous landmass consisting of what is now modern South America, Africa, Antarctica, Australia, New Zealand, and New Guinea.[3] [4]
La Matilde consists primarily of sedimentary rocks. It includes claystone, coal beds, conglomerates, siltstones, sandstones, and volcanic tuff. La Matilde overlies but sometimes intersperses with the Middle Jurassic Chon Aike Formation.[5] The two formations are the subunits of the Bahía Laura Group.[6]
La Matilde is known for the abundant fossils recovered from it. Notable fossil localities in the formation include the Cerro Cuadrado Petrified Forest, the Cerro Madre e Hija Petrified Forest, and the remains and trace fossils (including trackways) of dinosaurs in the Laguna Manantiales Farm.[7] [8]
Fossil taxa recovered from the La Matilde Formation include:[9] [10]