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Cretaceous Tertiary Extinction

The Cretaceous Tertiary event, taking place 70-65 million years ago, killed off 75% of all species, including the dinosaurs. This extinction cleared the way for mammals and birds, where before dinosaur were the dominant land species. Avian dinosaur fossils are the only ones found after the K-T boundary. Possible causes:

Impact Event: an asteroid 10-15 km or 6-9 miles in diameter impacted Earth at Chicxulub, in Mexico's Yucatan Peninsula. The explosion would have been a billion times larger than the nuclear bomb dropped on Hiroshima.

Flood Basalt Eruption: Deccan Traps flood basalt erupted for 800,000 years during the K-T boundary period, it would have exacerbated the devastation caused by the asteroid impact and would have slowed down the recovery of organisms.