The Cretaceous Period

dinosaurs · geology · mesozoic era

Age of dinosaurs. The Cretaceous Period was when dinosaurs ruled the planet, from about 143 million years ago until 66 million years ago. It was the longest geological period ever, stretching for about 77 million years.

Chalk deposits. The word Cretaceous comes from the Latin word for chalk because thick layers of chalk built up during this time, especially in the second half of the period. You can find these ancient chalk deposits in places like the white cliffs of Dover.

The extinction event. The Cretaceous ended with a catastrophic bang when a massive asteroid crashed into Earth 66 million years ago, wiping out most of the dinosaurs and changing life forever.

Long lasting period. At 77 million years long, the Cretaceous is not just the longest period of the Mesozoic Era but also the longest geological period in all of Earth's recorded history.

The letter K. Scientists often abbreviate the Cretaceous Period as K, which comes from its German name Kreide rather than the English word Cretaceous.