The Cenozoic Era
![Image of mammals during the Miocene Epoch of the Cenozoic Era](g-images/miocene-scene001.webp)
Rendering of possible scene during the Miocene Epoch
The Cenozoic is the Age of Mammals as they have grown to dominate the planet.
The Age of Mammals
Quaternary Period
- Holocene
- Pleistocene
Present-2 million years ago
Marked by increases and decreases in global glaciation, Bering Land Bridge. The beginnings of Man, minor mass extinctions continue around the globe
- Miocene
- Pliocene
2-23 million years ago
North America crashes into South America, Isthmus of Panama rises, Antarctica ices over, glaciers spread across high mountains and polar oceans.
Mountain building
15-30 million years ago
Vulcanism and mountain building in western North America: the modern Rockies are built, Basin & Range Province is built, Coast Ranges are pushed up
- Oligocene
- Eocene
- Paleocene
23-65 million years ago
Paleocene-Eocene Thermal Maximum Extinction Event: 55.5 million years ago.
Eocene Maximum Thermal Event: 47 million years ago. Last major global warming event
Laramide and Sevier Orogenies
63-65 million years ago
Overlapping mountain building events in the western US and Canada along the Cordillera and to the west: the Ancestral Rockies and the Colorado Plateau pushed up
Cretaceous-Paleogene Extinction Event, K-T Boundary
65 million years ago
Asteroid impact near the Yucatan peninsula, postulated to have combined with on-going geological and atmospheric processes to cause global climatic conditions that wiped out the dinosaurs
![An artist's rendition of mammals of the early Pleistocene Epoch](g-images/pleistocene-mammals001-plos.webp)
Mammals of the early Pleistocene
![The iridium marker at the K-T Boundary](g-images/kt-boundary001.webp)
The thin white layer above the coal and below the sandstone is the iridium marking the K-T Boundary
Maps are © Ron Blakey, NAU Geology, Deep Time Maps
Lower image courtesy of The Public Library of Science, CCA 3.0 License
Bottom photo courtesy of TheArmchairExplorer, CCA-by-SA 3.0 License