Uintan | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chronology | |||||||||||||
| |||||||||||||
Formerly part of | Tertiary Period/System | ||||||||||||
Etymology | |||||||||||||
Name formality | Formal | ||||||||||||
Usage information | |||||||||||||
Celestial body | Earth | ||||||||||||
Regional usage | Global (ICS) | ||||||||||||
Time scale(s) used | ICS Time Scale | ||||||||||||
Definition | |||||||||||||
Chronological unit | Age | ||||||||||||
Stratigraphic unit | Stage | ||||||||||||
Time span formality | Formal | ||||||||||||
Upper boundary definition candidates | Calcareous nannofossil near LAD of the Haptophyte Reticulofenestra reticulata | ||||||||||||
Upper boundary GSSP candidate section(s) | Contessa highway section, Gubbio, Central Apennines, Italy |
The Uintan North American Stage is the North American faunal stage, typically set from 46,200,000 to 42,000,000 years before present lasting 4.2 million years. [3] The Uintan Stage is a key part of the North American Land Mammal Age. In the Uinta Basin, a thriving subtropical ecosystem was formed at around 46.0 million years ago. It falls within the Eocene epoch, preceded by the Bridgerian and followed by the Duchesnean NALMA stages. [4] The Uinta Formation is a key piece of this geologic stage. Mammalian sabretooths evolved and became dominant predators in the now-Western United States. These included Apataelurus , Diegoaelurus, and Machaeroides . [5] [6]
The Uintan is considered to be contained within the Lutetian sharing the upper boundary and contains the following substages: