65.5 – 55.8 MILLION: PALEOCENE

- Epoch begins with earth devestated by asteroid impact;
- North America and Eurasia connected off and on;
- Africa, South America, Antarctica, Australia, and India
(an island continent) continue to separate; - Pacific Ocean shrinks as Atlantic Ocean widens;
- Climate warm and humid world-wide;
- Ferns fill post-asteroid world until forests regrow;
- Mammals, though still small “explode” into the land niches formely dominated by the dinosaurs;
- Large, flightless birds become top predators;
- Flowering plants (angiosperms) flourish & spread.
Name | Diameter (km) | Age (megayears) | Dating method | Morphological type | Notes |
---|---|---|---|---|---|
Chicxulub, Yucatan, Mexico | 150 | 66.043 ±0.011 | 40Ar/39Ar | CONFIRMED Peak ring basin | Cretaceous-Paleogene |
Eagle Butte, Alberta | 10 | <65 | Geological dating | CONFIRMED Complex | Shatter-coned Cretaceous rocks |
Parry Peninsula, NWT | 160 | <65 | K/T boundary timeframe | IMPROBABLE Complex |